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         rcu_read_lock();
  78         curr_router = rcu_dereference(orig_ifinfo->router);
  79         if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
  80                 curr_router = NULL;
  81         rcu_read_unlock();
  82
  83         /* route deleted */
  84         if ((curr_router) && (!neigh_node)) {
  85                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  86                            "Deleting route towards: %pM\n", orig_node->orig);
  87                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  88                                           "Deleted route towards originator");
  89
  90         /* route added */
  91         } else if ((!curr_router) && (neigh_node)) {
  92                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  93                            "Adding route towards: %pM (via %pM)\n",
  94                            orig_node->orig, neigh_node->addr);
  95         /* route changed */
  96         } else if (neigh_node && curr_router) {
  97                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  98                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  99                            orig_node->orig, neigh_node->addr,
 100                            curr_router->addr);
 101         }
 102
 103         if (curr_router)
 104                 batadv_neigh_node_put(curr_router);
 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         /* increase refcount of new best neighbor */
 117         if (neigh_node)
 118                 kref_get(&neigh_node->refcount);
 119
 120         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 121         spin_unlock_bh(&orig_node->neigh_list_lock);
 122         batadv_orig_ifinfo_put(orig_ifinfo);
 123
 124         /* decrease refcount of previous best neighbor */
 125         if (curr_router)
 126                 batadv_neigh_node_put(curr_router);
 127 }
 128
 129 /**
 130  * batadv_update_route - set the router for this originator
 131  * @bat_priv: the bat priv with all the soft interface information
 132  * @orig_node: orig node which is to be configured
 133  * @recv_if: the receive interface for which this route is set
 134  * @neigh_node: neighbor which should be the next router
 135  */
 136 void batadv_update_route(struct batadv_priv *bat_priv,
 137                          struct batadv_orig_node *orig_node,
 138                          struct batadv_hard_iface *recv_if,
 139                          struct batadv_neigh_node *neigh_node)
 140 {
 141         struct batadv_neigh_node *router = NULL;
 142
 143         if (!orig_node)
 144                 goto out;
 145
 146         router = batadv_orig_router_get(orig_node, recv_if);
 147
 148         if (router != neigh_node)
 149                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 150
 151 out:
 152         if (router)
 153                 batadv_neigh_node_put(router);
 154 }
 155
 156 /**
 157  * batadv_window_protected - checks whether the host restarted and is in the
 158  *  protection time.
 159  * @bat_priv: the bat priv with all the soft interface information
 160  * @seq_num_diff: difference between the current/received sequence number and
 161  *  the last sequence number
 162  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 163  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 164  *  is detected
 165  * @protection_started: is set to true if the protection window was started,
 166  *   doesn't change otherwise.
 167  *
 168  * Return:
 169  *  false if the packet is to be accepted.
 170  *  true if the packet is to be ignored.
 171  */
 172 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 173                              s32 seq_old_max_diff, unsigned long *last_reset,
 174                              bool *protection_started)
 175 {
 176         if (seq_num_diff <= -seq_old_max_diff ||
 177             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 178                 if (!batadv_has_timed_out(*last_reset,
 179                                           BATADV_RESET_PROTECTION_MS))
 180                         return true;
 181
 182                 *last_reset = jiffies;
 183                 if (protection_started)
 184                         *protection_started = true;
 185                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 186                            "old packet received, start protection\n");
 187         }
 188
 189         return false;
 190 }
 191
 192 bool batadv_check_management_packet(struct sk_buff *skb,
 193                                     struct batadv_hard_iface *hard_iface,
 194                                     int header_len)
 195 {
 196         struct ethhdr *ethhdr;
 197
 198         /* drop packet if it has not necessary minimum size */
 199         if (unlikely(!pskb_may_pull(skb, header_len)))
 200                 return false;
 201
 202         ethhdr = eth_hdr(skb);
 203
 204         /* packet with broadcast indication but unicast recipient */
 205         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 206                 return false;
 207
 208         /* packet with broadcast sender address */
 209         if (is_broadcast_ether_addr(ethhdr->h_source))
 210                 return false;
 211
 212         /* create a copy of the skb, if needed, to modify it. */
 213         if (skb_cow(skb, 0) < 0)
 214                 return false;
 215
 216         /* keep skb linear */
 217         if (skb_linearize(skb) < 0)
 218                 return false;
 219
 220         return true;
 221 }
 222
 223 /**
 224  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 225  * @bat_priv: the bat priv with all the soft interface information
 226  * @skb: icmp packet to process
 227  *
 228  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 229  * otherwise.
 230  */
 231 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 232                                       struct sk_buff *skb)
 233 {
 234         struct batadv_hard_iface *primary_if = NULL;
 235         struct batadv_orig_node *orig_node = NULL;
 236         struct batadv_icmp_header *icmph;
 237         int res, ret = NET_RX_DROP;
 238
 239         icmph = (struct batadv_icmp_header *)skb->data;
 240
 241         switch (icmph->msg_type) {
 242         case BATADV_ECHO_REPLY:
 243         case BATADV_DESTINATION_UNREACHABLE:
 244         case BATADV_TTL_EXCEEDED:
 245                 /* receive the packet */
 246                 if (skb_linearize(skb) < 0)
 247                         break;
 248
 249                 batadv_socket_receive_packet(icmph, skb->len);
 250                 break;
 251         case BATADV_ECHO_REQUEST:
 252                 /* answer echo request (ping) */
 253                 primary_if = batadv_primary_if_get_selected(bat_priv);
 254                 if (!primary_if)
 255                         goto out;
 256
 257                 /* get routing information */
 258                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 259                 if (!orig_node)
 260                         goto out;
 261
 262                 /* create a copy of the skb, if needed, to modify it. */
 263                 if (skb_cow(skb, ETH_HLEN) < 0)
 264                         goto out;
 265
 266                 icmph = (struct batadv_icmp_header *)skb->data;
 267
 268                 ether_addr_copy(icmph->dst, icmph->orig);
 269                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 270                 icmph->msg_type = BATADV_ECHO_REPLY;
 271                 icmph->ttl = BATADV_TTL;
 272
 273                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 274                 if (res == -1)
 275                         goto out;
 276
 277                 ret = NET_RX_SUCCESS;
 278
 279                 break;
 280         case BATADV_TP:
 281                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
 282                         goto out;
 283
 284                 batadv_tp_meter_recv(bat_priv, skb);
 285                 ret = NET_RX_SUCCESS;
 286                 goto out;
 287         default:
 288                 /* drop unknown type */
 289                 goto out;
 290         }
 291 out:
 292         if (primary_if)
 293                 batadv_hardif_put(primary_if);
 294         if (orig_node)
 295                 batadv_orig_node_put(orig_node);
 296         return ret;
 297 }
 298
 299 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 300                                          struct sk_buff *skb)
 301 {
 302         struct batadv_hard_iface *primary_if = NULL;
 303         struct batadv_orig_node *orig_node = NULL;
 304         struct batadv_icmp_packet *icmp_packet;
 305         int res, ret = NET_RX_DROP;
 306
 307         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 308
 309         /* send TTL exceeded if packet is an echo request (traceroute) */
 310         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 311                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 312                          icmp_packet->orig, icmp_packet->dst);
 313                 goto out;
 314         }
 315
 316         primary_if = batadv_primary_if_get_selected(bat_priv);
 317         if (!primary_if)
 318                 goto out;
 319
 320         /* get routing information */
 321         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 322         if (!orig_node)
 323                 goto out;
 324
 325         /* create a copy of the skb, if needed, to modify it. */
 326         if (skb_cow(skb, ETH_HLEN) < 0)
 327                 goto out;
 328
 329         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 330
 331         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 332         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 333         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 334         icmp_packet->ttl = BATADV_TTL;
 335
 336         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 337         if (res != -1)
 338                 ret = NET_RX_SUCCESS;
 339
 340 out:
 341         if (primary_if)
 342                 batadv_hardif_put(primary_if);
 343         if (orig_node)
 344                 batadv_orig_node_put(orig_node);
 345         return ret;
 346 }
 347
 348 int batadv_recv_icmp_packet(struct sk_buff *skb,
 349                             struct batadv_hard_iface *recv_if)
 350 {
 351         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 352         struct batadv_icmp_header *icmph;
 353         struct batadv_icmp_packet_rr *icmp_packet_rr;
 354         struct ethhdr *ethhdr;
 355         struct batadv_orig_node *orig_node = NULL;
 356         int hdr_size = sizeof(struct batadv_icmp_header);
 357         int res, ret = NET_RX_DROP;
 358
 359         /* drop packet if it has not necessary minimum size */
 360         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 361                 goto out;
 362
 363         ethhdr = eth_hdr(skb);
 364
 365         /* packet with unicast indication but broadcast recipient */
 366         if (is_broadcast_ether_addr(ethhdr->h_dest))
 367                 goto out;
 368
 369         /* packet with broadcast sender address */
 370         if (is_broadcast_ether_addr(ethhdr->h_source))
 371                 goto out;
 372
 373         /* not for me */
 374         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 375                 goto out;
 376
 377         icmph = (struct batadv_icmp_header *)skb->data;
 378
 379         /* add record route information if not full */
 380         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 381              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 382             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 383                 if (skb_linearize(skb) < 0)
 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                 ethhdr = eth_hdr(skb);
 391                 icmph = (struct batadv_icmp_header *)skb->data;
 392                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 393                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 394                         goto out;
 395
 396                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 397                                 ethhdr->h_dest);
 398                 icmp_packet_rr->rr_cur++;
 399         }
 400
 401         /* packet for me */
 402         if (batadv_is_my_mac(bat_priv, icmph->dst))
 403                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 404
 405         /* TTL exceeded */
 406         if (icmph->ttl < 2)
 407                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 408
 409         /* get routing information */
 410         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 411         if (!orig_node)
 412                 goto out;
 413
 414         /* create a copy of the skb, if needed, to modify it. */
 415         if (skb_cow(skb, ETH_HLEN) < 0)
 416                 goto out;
 417
 418         icmph = (struct batadv_icmp_header *)skb->data;
 419
 420         /* decrement ttl */
 421         icmph->ttl--;
 422
 423         /* route it */
 424         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 425         if (res != -1)
 426                 ret = NET_RX_SUCCESS;
 427
 428 out:
 429         if (orig_node)
 430                 batadv_orig_node_put(orig_node);
 431         return ret;
 432 }
 433
 434 /**
 435  * batadv_check_unicast_packet - Check for malformed unicast packets
 436  * @bat_priv: the bat priv with all the soft interface information
 437  * @skb: packet to check
 438  * @hdr_size: size of header to pull
 439  *
 440  * Check for short header and bad addresses in given packet.
 441  *
 442  * Return: negative value when check fails and 0 otherwise. The negative value
 443  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 444  * destination or source, and -EREMOTE for non-local (other host) destination.
 445  */
 446 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 447                                        struct sk_buff *skb, int hdr_size)
 448 {
 449         struct ethhdr *ethhdr;
 450
 451         /* drop packet if it has not necessary minimum size */
 452         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 453                 return -ENODATA;
 454
 455         ethhdr = eth_hdr(skb);
 456
 457         /* packet with unicast indication but broadcast recipient */
 458         if (is_broadcast_ether_addr(ethhdr->h_dest))
 459                 return -EBADR;
 460
 461         /* packet with broadcast sender address */
 462         if (is_broadcast_ether_addr(ethhdr->h_source))
 463                 return -EBADR;
 464
 465         /* not for me */
 466         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 467                 return -EREMOTE;
 468
 469         return 0;
 470 }
 471
 472 /**
 473  * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
 474  * @orig_node: originator node whose last bonding candidate should be retrieved
 475  *
 476  * Return: last bonding candidate of router or NULL if not found
 477  *
 478  * The object is returned with refcounter increased by 1.
 479  */
 480 static struct batadv_orig_ifinfo *
 481 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
 482 {
 483         struct batadv_orig_ifinfo *last_bonding_candidate;
 484
 485         spin_lock_bh(&orig_node->neigh_list_lock);
 486         last_bonding_candidate = orig_node->last_bonding_candidate;
 487
 488         if (last_bonding_candidate)
 489                 kref_get(&last_bonding_candidate->refcount);
 490         spin_unlock_bh(&orig_node->neigh_list_lock);
 491
 492         return last_bonding_candidate;
 493 }
 494
 495 /**
 496  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 497  * @orig_node: originator node whose bonding candidates should be replaced
 498  * @new_candidate: new bonding candidate or NULL
 499  */
 500 static void
 501 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 502                             struct batadv_orig_ifinfo *new_candidate)
 503 {
 504         struct batadv_orig_ifinfo *old_candidate;
 505
 506         spin_lock_bh(&orig_node->neigh_list_lock);
 507         old_candidate = orig_node->last_bonding_candidate;
 508
 509         if (new_candidate)
 510                 kref_get(&new_candidate->refcount);
 511         orig_node->last_bonding_candidate = new_candidate;
 512         spin_unlock_bh(&orig_node->neigh_list_lock);
 513
 514         if (old_candidate)
 515                 batadv_orig_ifinfo_put(old_candidate);
 516 }
 517
 518 /**
 519  * batadv_find_router - find a suitable router for this originator
 520  * @bat_priv: the bat priv with all the soft interface information
 521  * @orig_node: the destination node
 522  * @recv_if: pointer to interface this packet was received on
 523  *
 524  * Return: the router which should be used for this orig_node on
 525  * this interface, or NULL if not available.
 526  */
 527 struct batadv_neigh_node *
 528 batadv_find_router(struct batadv_priv *bat_priv,
 529                    struct batadv_orig_node *orig_node,
 530                    struct batadv_hard_iface *recv_if)
 531 {
 532         struct batadv_algo_ops *bao = bat_priv->algo_ops;
 533         struct batadv_neigh_node *first_candidate_router = NULL;
 534         struct batadv_neigh_node *next_candidate_router = NULL;
 535         struct batadv_neigh_node *router, *cand_router = NULL;
 536         struct batadv_neigh_node *last_cand_router = NULL;
 537         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 538         struct batadv_orig_ifinfo *next_candidate = NULL;
 539         struct batadv_orig_ifinfo *last_candidate;
 540         bool last_candidate_found = false;
 541
 542         if (!orig_node)
 543                 return NULL;
 544
 545         router = batadv_orig_router_get(orig_node, recv_if);
 546
 547         if (!router)
 548                 return router;
 549
 550         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 551          * and if activated.
 552          */
 553         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 554                 return router;
 555
 556         /* bonding: loop through the list of possible routers found
 557          * for the various outgoing interfaces and find a candidate after
 558          * the last chosen bonding candidate (next_candidate). If no such
 559          * router is found, use the first candidate found (the previously
 560          * chosen bonding candidate might have been the last one in the list).
 561          * If this can't be found either, return the previously chosen
 562          * router - obviously there are no other candidates.
 563          */
 564         rcu_read_lock();
 565         last_candidate = batadv_last_bonding_get(orig_node);
 566         if (last_candidate)
 567                 last_cand_router = rcu_dereference(last_candidate->router);
 568
 569         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 570                 /* acquire some structures and references ... */
 571                 if (!kref_get_unless_zero(&cand->refcount))
 572                         continue;
 573
 574                 cand_router = rcu_dereference(cand->router);
 575                 if (!cand_router)
 576                         goto next;
 577
 578                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 579                         cand_router = NULL;
 580                         goto next;
 581                 }
 582
 583                 /* alternative candidate should be good enough to be
 584                  * considered
 585                  */
 586                 if (!bao->neigh.is_similar_or_better(cand_router,
 587                                                      cand->if_outgoing, router,
 588                                                      recv_if))
 589                         goto next;
 590
 591                 /* don't use the same router twice */
 592                 if (last_cand_router == cand_router)
 593                         goto next;
 594
 595                 /* mark the first possible candidate */
 596                 if (!first_candidate) {
 597                         kref_get(&cand_router->refcount);
 598                         kref_get(&cand->refcount);
 599                         first_candidate = cand;
 600                         first_candidate_router = cand_router;
 601                 }
 602
 603                 /* check if the loop has already passed the previously selected
 604                  * candidate ... this function should select the next candidate
 605                  * AFTER the previously used bonding candidate.
 606                  */
 607                 if (!last_candidate || last_candidate_found) {
 608                         next_candidate = cand;
 609                         next_candidate_router = cand_router;
 610                         break;
 611                 }
 612
 613                 if (last_candidate == cand)
 614                         last_candidate_found = true;
 615 next:
 616                 /* free references */
 617                 if (cand_router) {
 618                         batadv_neigh_node_put(cand_router);
 619                         cand_router = NULL;
 620                 }
 621                 batadv_orig_ifinfo_put(cand);
 622         }
 623         rcu_read_unlock();
 624
 625         /* After finding candidates, handle the three cases:
 626          * 1) there is a next candidate, use that
 627          * 2) there is no next candidate, use the first of the list
 628          * 3) there is no candidate at all, return the default router
 629          */
 630         if (next_candidate) {
 631                 batadv_neigh_node_put(router);
 632
 633                 kref_get(&next_candidate_router->refcount);
 634                 router = next_candidate_router;
 635                 batadv_last_bonding_replace(orig_node, next_candidate);
 636         } else if (first_candidate) {
 637                 batadv_neigh_node_put(router);
 638
 639                 kref_get(&first_candidate_router->refcount);
 640                 router = first_candidate_router;
 641                 batadv_last_bonding_replace(orig_node, first_candidate);
 642         } else {
 643                 batadv_last_bonding_replace(orig_node, NULL);
 644         }
 645
 646         /* cleanup of candidates */
 647         if (first_candidate) {
 648                 batadv_neigh_node_put(first_candidate_router);
 649                 batadv_orig_ifinfo_put(first_candidate);
 650         }
 651
 652         if (next_candidate) {
 653                 batadv_neigh_node_put(next_candidate_router);
 654                 batadv_orig_ifinfo_put(next_candidate);
 655         }
 656
 657         if (last_candidate)
 658                 batadv_orig_ifinfo_put(last_candidate);
 659
 660         return router;
 661 }
 662
 663 static int batadv_route_unicast_packet(struct sk_buff *skb,
 664                                        struct batadv_hard_iface *recv_if)
 665 {
 666         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 667         struct batadv_orig_node *orig_node = NULL;
 668         struct batadv_unicast_packet *unicast_packet;
 669         struct ethhdr *ethhdr = eth_hdr(skb);
 670         int res, hdr_len, ret = NET_RX_DROP;
 671         unsigned int len;
 672
 673         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 674
 675         /* TTL exceeded */
 676         if (unicast_packet->ttl < 2) {
 677                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 678                          ethhdr->h_source, unicast_packet->dest);
 679                 goto out;
 680         }
 681
 682         /* get routing information */
 683         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 684
 685         if (!orig_node)
 686                 goto out;
 687
 688         /* create a copy of the skb, if needed, to modify it. */
 689         if (skb_cow(skb, ETH_HLEN) < 0)
 690                 goto out;
 691
 692         /* decrement ttl */
 693         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 694         unicast_packet->ttl--;
 695
 696         switch (unicast_packet->packet_type) {
 697         case BATADV_UNICAST_4ADDR:
 698                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 699                 break;
 700         case BATADV_UNICAST:
 701                 hdr_len = sizeof(struct batadv_unicast_packet);
 702                 break;
 703         default:
 704                 /* other packet types not supported - yet */
 705                 hdr_len = -1;
 706                 break;
 707         }
 708
 709         if (hdr_len > 0)
 710                 batadv_skb_set_priority(skb, hdr_len);
 711
 712         len = skb->len;
 713         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 714         if (res == -1)
 715                 goto out;
 716
 717         /* translate transmit result into receive result */
 718         if (res == NET_XMIT_SUCCESS) {
 719                 /* skb was transmitted and consumed */
 720                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 721                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 722                                    len + ETH_HLEN);
 723         }
 724
 725         ret = NET_RX_SUCCESS;
 726
 727 out:
 728         if (orig_node)
 729                 batadv_orig_node_put(orig_node);
 730         return ret;
 731 }
 732
 733 /**
 734  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 735  * @bat_priv: the bat priv with all the soft interface information
 736  * @unicast_packet: the unicast header to be updated
 737  * @dst_addr: the payload destination
 738  * @vid: VLAN identifier
 739  *
 740  * Search the translation table for dst_addr and update the unicast header with
 741  * the new corresponding information (originator address where the destination
 742  * client currently is and its known TTVN)
 743  *
 744  * Return: true if the packet header has been updated, false otherwise
 745  */
 746 static bool
 747 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 748                               struct batadv_unicast_packet *unicast_packet,
 749                               u8 *dst_addr, unsigned short vid)
 750 {
 751         struct batadv_orig_node *orig_node = NULL;
 752         struct batadv_hard_iface *primary_if = NULL;
 753         bool ret = false;
 754         u8 *orig_addr, orig_ttvn;
 755
 756         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 757                 primary_if = batadv_primary_if_get_selected(bat_priv);
 758                 if (!primary_if)
 759                         goto out;
 760                 orig_addr = primary_if->net_dev->dev_addr;
 761                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 762         } else {
 763                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 764                                                      vid);
 765                 if (!orig_node)
 766                         goto out;
 767
 768                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 769                         goto out;
 770
 771                 orig_addr = orig_node->orig;
 772                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 773         }
 774
 775         /* update the packet header */
 776         ether_addr_copy(unicast_packet->dest, orig_addr);
 777         unicast_packet->ttvn = orig_ttvn;
 778
 779         ret = true;
 780 out:
 781         if (primary_if)
 782                 batadv_hardif_put(primary_if);
 783         if (orig_node)
 784                 batadv_orig_node_put(orig_node);
 785
 786         return ret;
 787 }
 788
 789 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 790                                       struct sk_buff *skb, int hdr_len)
 791 {
 792         struct batadv_unicast_packet *unicast_packet;
 793         struct batadv_hard_iface *primary_if;
 794         struct batadv_orig_node *orig_node;
 795         u8 curr_ttvn, old_ttvn;
 796         struct ethhdr *ethhdr;
 797         unsigned short vid;
 798         int is_old_ttvn;
 799
 800         /* check if there is enough data before accessing it */
 801         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 802                 return false;
 803
 804         /* create a copy of the skb (in case of for re-routing) to modify it. */
 805         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 806                 return false;
 807
 808         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 809         vid = batadv_get_vid(skb, hdr_len);
 810         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 811
 812         /* check if the destination client was served by this node and it is now
 813          * roaming. In this case, it means that the node has got a ROAM_ADV
 814          * message and that it knows the new destination in the mesh to re-route
 815          * the packet to
 816          */
 817         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 818                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 819                                                   ethhdr->h_dest, vid))
 820                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 821                                                bat_priv,
 822                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 823                                                unicast_packet->dest,
 824                                                ethhdr->h_dest);
 825                 /* at this point the mesh destination should have been
 826                  * substituted with the originator address found in the global
 827                  * table. If not, let the packet go untouched anyway because
 828                  * there is nothing the node can do
 829                  */
 830                 return true;
 831         }
 832
 833         /* retrieve the TTVN known by this node for the packet destination. This
 834          * value is used later to check if the node which sent (or re-routed
 835          * last time) the packet had an updated information or not
 836          */
 837         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 838         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 839                 orig_node = batadv_orig_hash_find(bat_priv,
 840                                                   unicast_packet->dest);
 841                 /* if it is not possible to find the orig_node representing the
 842                  * destination, the packet can immediately be dropped as it will
 843                  * not be possible to deliver it
 844                  */
 845                 if (!orig_node)
 846                         return false;
 847
 848                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 849                 batadv_orig_node_put(orig_node);
 850         }
 851
 852         /* check if the TTVN contained in the packet is fresher than what the
 853          * node knows
 854          */
 855         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 856         if (!is_old_ttvn)
 857                 return true;
 858
 859         old_ttvn = unicast_packet->ttvn;
 860         /* the packet was forged based on outdated network information. Its
 861          * destination can possibly be updated and forwarded towards the new
 862          * target host
 863          */
 864         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 865                                           ethhdr->h_dest, vid)) {
 866                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 867                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 868                                        unicast_packet->dest, ethhdr->h_dest,
 869                                        old_ttvn, curr_ttvn);
 870                 return true;
 871         }
 872
 873         /* the packet has not been re-routed: either the destination is
 874          * currently served by this node or there is no destination at all and
 875          * it is possible to drop the packet
 876          */
 877         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 878                 return false;
 879
 880         /* update the header in order to let the packet be delivered to this
 881          * node's soft interface
 882          */
 883         primary_if = batadv_primary_if_get_selected(bat_priv);
 884         if (!primary_if)
 885                 return false;
 886
 887         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 888
 889         batadv_hardif_put(primary_if);
 890
 891         unicast_packet->ttvn = curr_ttvn;
 892
 893         return true;
 894 }
 895
 896 /**
 897  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 898  *      are in the unicast number space but not yet known to the implementation
 899  * @skb: unicast tvlv packet to process
 900  * @recv_if: pointer to interface this packet was received on
 901  *
 902  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 903  * otherwise.
 904  */
 905 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 906                                          struct batadv_hard_iface *recv_if)
 907 {
 908         struct batadv_unicast_packet *unicast_packet;
 909         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 910         int check, hdr_size = sizeof(*unicast_packet);
 911
 912         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 913         if (check < 0)
 914                 return NET_RX_DROP;
 915
 916         /* we don't know about this type, drop it. */
 917         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 918         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 919                 return NET_RX_DROP;
 920
 921         return batadv_route_unicast_packet(skb, recv_if);
 922 }
 923
 924 int batadv_recv_unicast_packet(struct sk_buff *skb,
 925                                struct batadv_hard_iface *recv_if)
 926 {
 927         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 928         struct batadv_unicast_packet *unicast_packet;
 929         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 930         u8 *orig_addr;
 931         struct batadv_orig_node *orig_node = NULL;
 932         int check, hdr_size = sizeof(*unicast_packet);
 933         enum batadv_subtype subtype;
 934         bool is4addr;
 935
 936         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 937         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 938
 939         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 940         /* the caller function should have already pulled 2 bytes */
 941         if (is4addr)
 942                 hdr_size = sizeof(*unicast_4addr_packet);
 943
 944         /* function returns -EREMOTE for promiscuous packets */
 945         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 946
 947         /* Even though the packet is not for us, we might save it to use for
 948          * decoding a later received coded packet
 949          */
 950         if (check == -EREMOTE)
 951                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 952
 953         if (check < 0)
 954                 return NET_RX_DROP;
 955         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 956                 return NET_RX_DROP;
 957
 958         /* packet for me */
 959         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 960                 if (is4addr) {
 961                         subtype = unicast_4addr_packet->subtype;
 962                         batadv_dat_inc_counter(bat_priv, subtype);
 963
 964                         /* Only payload data should be considered for speedy
 965                          * join. For example, DAT also uses unicast 4addr
 966                          * types, but those packets should not be considered
 967                          * for speedy join, since the clients do not actually
 968                          * reside at the sending originator.
 969                          */
 970                         if (subtype == BATADV_P_DATA) {
 971                                 orig_addr = unicast_4addr_packet->src;
 972                                 orig_node = batadv_orig_hash_find(bat_priv,
 973                                                                   orig_addr);
 974                         }
 975                 }
 976
 977                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 978                                                           hdr_size))
 979                         goto rx_success;
 980                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 981                                                         hdr_size))
 982                         goto rx_success;
 983
 984                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
 985                                     orig_node);
 986
 987 rx_success:
 988                 if (orig_node)
 989                         batadv_orig_node_put(orig_node);
 990
 991                 return NET_RX_SUCCESS;
 992         }
 993
 994         return batadv_route_unicast_packet(skb, recv_if);
 995 }
 996
 997 /**
 998  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 999  * @skb: unicast tvlv packet to process
1000  * @recv_if: pointer to interface this packet was received on
1001  *
1002  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1003  * otherwise.
1004  */
1005 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1006                              struct batadv_hard_iface *recv_if)
1007 {
1008         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1009         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1010         unsigned char *tvlv_buff;
1011         u16 tvlv_buff_len;
1012         int hdr_size = sizeof(*unicast_tvlv_packet);
1013         int ret = NET_RX_DROP;
1014
1015         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1016                 return NET_RX_DROP;
1017
1018         /* the header is likely to be modified while forwarding */
1019         if (skb_cow(skb, hdr_size) < 0)
1020                 return NET_RX_DROP;
1021
1022         /* packet needs to be linearized to access the tvlv content */
1023         if (skb_linearize(skb) < 0)
1024                 return NET_RX_DROP;
1025
1026         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1027
1028         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1029         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1030
1031         if (tvlv_buff_len > skb->len - hdr_size)
1032                 return NET_RX_DROP;
1033
1034         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1035                                              unicast_tvlv_packet->src,
1036                                              unicast_tvlv_packet->dst,
1037                                              tvlv_buff, tvlv_buff_len);
1038
1039         if (ret != NET_RX_SUCCESS)
1040                 ret = batadv_route_unicast_packet(skb, recv_if);
1041         else
1042                 consume_skb(skb);
1043
1044         return ret;
1045 }
1046
1047 /**
1048  * batadv_recv_frag_packet - process received fragment
1049  * @skb: the received fragment
1050  * @recv_if: interface that the skb is received on
1051  *
1052  * This function does one of the three following things: 1) Forward fragment, if
1053  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1054  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1055  *
1056  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1057  */
1058 int batadv_recv_frag_packet(struct sk_buff *skb,
1059                             struct batadv_hard_iface *recv_if)
1060 {
1061         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1062         struct batadv_orig_node *orig_node_src = NULL;
1063         struct batadv_frag_packet *frag_packet;
1064         int ret = NET_RX_DROP;
1065
1066         if (batadv_check_unicast_packet(bat_priv, skb,
1067                                         sizeof(*frag_packet)) < 0)
1068                 goto out;
1069
1070         frag_packet = (struct batadv_frag_packet *)skb->data;
1071         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1072         if (!orig_node_src)
1073                 goto out;
1074
1075         skb->priority = frag_packet->priority + 256;
1076
1077         /* Route the fragment if it is not for us and too big to be merged. */
1078         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1079             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1080                 ret = NET_RX_SUCCESS;
1081                 goto out;
1082         }
1083
1084         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1085         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1086
1087         /* Add fragment to buffer and merge if possible. */
1088         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1089                 goto out;
1090
1091         /* Deliver merged packet to the appropriate handler, if it was
1092          * merged
1093          */
1094         if (skb)
1095                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1096                                        &recv_if->batman_adv_ptype, NULL);
1097
1098         ret = NET_RX_SUCCESS;
1099
1100 out:
1101         if (orig_node_src)
1102                 batadv_orig_node_put(orig_node_src);
1103
1104         return ret;
1105 }
1106
1107 int batadv_recv_bcast_packet(struct sk_buff *skb,
1108                              struct batadv_hard_iface *recv_if)
1109 {
1110         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1111         struct batadv_orig_node *orig_node = NULL;
1112         struct batadv_bcast_packet *bcast_packet;
1113         struct ethhdr *ethhdr;
1114         int hdr_size = sizeof(*bcast_packet);
1115         int ret = NET_RX_DROP;
1116         s32 seq_diff;
1117         u32 seqno;
1118
1119         /* drop packet if it has not necessary minimum size */
1120         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1121                 goto out;
1122
1123         ethhdr = eth_hdr(skb);
1124
1125         /* packet with broadcast indication but unicast recipient */
1126         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1127                 goto out;
1128
1129         /* packet with broadcast sender address */
1130         if (is_broadcast_ether_addr(ethhdr->h_source))
1131                 goto out;
1132
1133         /* ignore broadcasts sent by myself */
1134         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1135                 goto out;
1136
1137         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1138
1139         /* ignore broadcasts originated by myself */
1140         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1141                 goto out;
1142
1143         if (bcast_packet->ttl < 2)
1144                 goto out;
1145
1146         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1147
1148         if (!orig_node)
1149                 goto out;
1150
1151         spin_lock_bh(&orig_node->bcast_seqno_lock);
1152
1153         seqno = ntohl(bcast_packet->seqno);
1154         /* check whether the packet is a duplicate */
1155         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1156                             seqno))
1157                 goto spin_unlock;
1158
1159         seq_diff = seqno - orig_node->last_bcast_seqno;
1160
1161         /* check whether the packet is old and the host just restarted. */
1162         if (batadv_window_protected(bat_priv, seq_diff,
1163                                     BATADV_BCAST_MAX_AGE,
1164                                     &orig_node->bcast_seqno_reset, NULL))
1165                 goto spin_unlock;
1166
1167         /* mark broadcast in flood history, update window position
1168          * if required.
1169          */
1170         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1171                 orig_node->last_bcast_seqno = seqno;
1172
1173         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1174
1175         /* check whether this has been sent by another originator before */
1176         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1177                 goto out;
1178
1179         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1180
1181         /* rebroadcast packet */
1182         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1183
1184         /* don't hand the broadcast up if it is from an originator
1185          * from the same backbone.
1186          */
1187         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1188                 goto out;
1189
1190         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1191                 goto rx_success;
1192         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1193                 goto rx_success;
1194
1195         /* broadcast for me */
1196         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1197
1198 rx_success:
1199         ret = NET_RX_SUCCESS;
1200         goto out;
1201
1202 spin_unlock:
1203         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1204 out:
1205         if (orig_node)
1206                 batadv_orig_node_put(orig_node);
1207         return ret;
1208 }