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 invalid sender address */
 200         if (!is_valid_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 == NET_XMIT_SUCCESS)
 266                         ret = NET_RX_SUCCESS;
 267
 268                 /* skb was consumed */
 269                 skb = NULL;
 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                 /* skb was consumed */
 278                 skb = NULL;
 279                 goto out;
 280         default:
 281                 /* drop unknown type */
 282                 goto out;
 283         }
 284 out:
 285         if (primary_if)
 286                 batadv_hardif_put(primary_if);
 287         if (orig_node)
 288                 batadv_orig_node_put(orig_node);
 289
 290         kfree_skb(skb);
 291
 292         return ret;
 293 }
 294
 295 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 296                                          struct sk_buff *skb)
 297 {
 298         struct batadv_hard_iface *primary_if = NULL;
 299         struct batadv_orig_node *orig_node = NULL;
 300         struct batadv_icmp_packet *icmp_packet;
 301         int res, ret = NET_RX_DROP;
 302
 303         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 304
 305         /* send TTL exceeded if packet is an echo request (traceroute) */
 306         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 307                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 308                          icmp_packet->orig, icmp_packet->dst);
 309                 goto out;
 310         }
 311
 312         primary_if = batadv_primary_if_get_selected(bat_priv);
 313         if (!primary_if)
 314                 goto out;
 315
 316         /* get routing information */
 317         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 318         if (!orig_node)
 319                 goto out;
 320
 321         /* create a copy of the skb, if needed, to modify it. */
 322         if (skb_cow(skb, ETH_HLEN) < 0)
 323                 goto out;
 324
 325         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 326
 327         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 328         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 329         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 330         icmp_packet->ttl = BATADV_TTL;
 331
 332         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 333         if (res == NET_RX_SUCCESS)
 334                 ret = NET_XMIT_SUCCESS;
 335
 336         /* skb was consumed */
 337         skb = NULL;
 338
 339 out:
 340         if (primary_if)
 341                 batadv_hardif_put(primary_if);
 342         if (orig_node)
 343                 batadv_orig_node_put(orig_node);
 344
 345         kfree_skb(skb);
 346
 347         return ret;
 348 }
 349
 350 int batadv_recv_icmp_packet(struct sk_buff *skb,
 351                             struct batadv_hard_iface *recv_if)
 352 {
 353         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 354         struct batadv_icmp_header *icmph;
 355         struct batadv_icmp_packet_rr *icmp_packet_rr;
 356         struct ethhdr *ethhdr;
 357         struct batadv_orig_node *orig_node = NULL;
 358         int hdr_size = sizeof(struct batadv_icmp_header);
 359         int res, ret = NET_RX_DROP;
 360
 361         /* drop packet if it has not necessary minimum size */
 362         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 363                 goto free_skb;
 364
 365         ethhdr = eth_hdr(skb);
 366
 367         /* packet with unicast indication but non-unicast recipient */
 368         if (!is_valid_ether_addr(ethhdr->h_dest))
 369                 goto free_skb;
 370
 371         /* packet with broadcast/multicast sender address */
 372         if (is_multicast_ether_addr(ethhdr->h_source))
 373                 goto free_skb;
 374
 375         /* not for me */
 376         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 377                 goto free_skb;
 378
 379         icmph = (struct batadv_icmp_header *)skb->data;
 380
 381         /* add record route information if not full */
 382         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 383              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 384             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 385                 if (skb_linearize(skb) < 0)
 386                         goto free_skb;
 387
 388                 /* create a copy of the skb, if needed, to modify it. */
 389                 if (skb_cow(skb, ETH_HLEN) < 0)
 390                         goto free_skb;
 391
 392                 ethhdr = eth_hdr(skb);
 393                 icmph = (struct batadv_icmp_header *)skb->data;
 394                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 395                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 396                         goto free_skb;
 397
 398                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 399                                 ethhdr->h_dest);
 400                 icmp_packet_rr->rr_cur++;
 401         }
 402
 403         /* packet for me */
 404         if (batadv_is_my_mac(bat_priv, icmph->dst))
 405                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 406
 407         /* TTL exceeded */
 408         if (icmph->ttl < 2)
 409                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 410
 411         /* get routing information */
 412         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 413         if (!orig_node)
 414                 goto free_skb;
 415
 416         /* create a copy of the skb, if needed, to modify it. */
 417         if (skb_cow(skb, ETH_HLEN) < 0)
 418                 goto put_orig_node;
 419
 420         icmph = (struct batadv_icmp_header *)skb->data;
 421
 422         /* decrement ttl */
 423         icmph->ttl--;
 424
 425         /* route it */
 426         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 427         if (res == NET_XMIT_SUCCESS)
 428                 ret = NET_RX_SUCCESS;
 429
 430         /* skb was consumed */
 431         skb = NULL;
 432
 433 put_orig_node:
 434         if (orig_node)
 435                 batadv_orig_node_put(orig_node);
 436 free_skb:
 437         kfree_skb(skb);
 438
 439         return ret;
 440 }
 441
 442 /**
 443  * batadv_check_unicast_packet - Check for malformed unicast packets
 444  * @bat_priv: the bat priv with all the soft interface information
 445  * @skb: packet to check
 446  * @hdr_size: size of header to pull
 447  *
 448  * Check for short header and bad addresses in given packet.
 449  *
 450  * Return: negative value when check fails and 0 otherwise. The negative value
 451  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 452  * destination or source, and -EREMOTE for non-local (other host) destination.
 453  */
 454 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 455                                        struct sk_buff *skb, int hdr_size)
 456 {
 457         struct ethhdr *ethhdr;
 458
 459         /* drop packet if it has not necessary minimum size */
 460         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 461                 return -ENODATA;
 462
 463         ethhdr = eth_hdr(skb);
 464
 465         /* packet with unicast indication but non-unicast recipient */
 466         if (!is_valid_ether_addr(ethhdr->h_dest))
 467                 return -EBADR;
 468
 469         /* packet with broadcast/multicast sender address */
 470         if (is_multicast_ether_addr(ethhdr->h_source))
 471                 return -EBADR;
 472
 473         /* not for me */
 474         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 475                 return -EREMOTE;
 476
 477         return 0;
 478 }
 479
 480 /**
 481  * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
 482  * @orig_node: originator node whose last bonding candidate should be retrieved
 483  *
 484  * Return: last bonding candidate of router or NULL if not found
 485  *
 486  * The object is returned with refcounter increased by 1.
 487  */
 488 static struct batadv_orig_ifinfo *
 489 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
 490 {
 491         struct batadv_orig_ifinfo *last_bonding_candidate;
 492
 493         spin_lock_bh(&orig_node->neigh_list_lock);
 494         last_bonding_candidate = orig_node->last_bonding_candidate;
 495
 496         if (last_bonding_candidate)
 497                 kref_get(&last_bonding_candidate->refcount);
 498         spin_unlock_bh(&orig_node->neigh_list_lock);
 499
 500         return last_bonding_candidate;
 501 }
 502
 503 /**
 504  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 505  * @orig_node: originator node whose bonding candidates should be replaced
 506  * @new_candidate: new bonding candidate or NULL
 507  */
 508 static void
 509 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 510                             struct batadv_orig_ifinfo *new_candidate)
 511 {
 512         struct batadv_orig_ifinfo *old_candidate;
 513
 514         spin_lock_bh(&orig_node->neigh_list_lock);
 515         old_candidate = orig_node->last_bonding_candidate;
 516
 517         if (new_candidate)
 518                 kref_get(&new_candidate->refcount);
 519         orig_node->last_bonding_candidate = new_candidate;
 520         spin_unlock_bh(&orig_node->neigh_list_lock);
 521
 522         if (old_candidate)
 523                 batadv_orig_ifinfo_put(old_candidate);
 524 }
 525
 526 /**
 527  * batadv_find_router - find a suitable router for this originator
 528  * @bat_priv: the bat priv with all the soft interface information
 529  * @orig_node: the destination node
 530  * @recv_if: pointer to interface this packet was received on
 531  *
 532  * Return: the router which should be used for this orig_node on
 533  * this interface, or NULL if not available.
 534  */
 535 struct batadv_neigh_node *
 536 batadv_find_router(struct batadv_priv *bat_priv,
 537                    struct batadv_orig_node *orig_node,
 538                    struct batadv_hard_iface *recv_if)
 539 {
 540         struct batadv_algo_ops *bao = bat_priv->algo_ops;
 541         struct batadv_neigh_node *first_candidate_router = NULL;
 542         struct batadv_neigh_node *next_candidate_router = NULL;
 543         struct batadv_neigh_node *router, *cand_router = NULL;
 544         struct batadv_neigh_node *last_cand_router = NULL;
 545         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 546         struct batadv_orig_ifinfo *next_candidate = NULL;
 547         struct batadv_orig_ifinfo *last_candidate;
 548         bool last_candidate_found = false;
 549
 550         if (!orig_node)
 551                 return NULL;
 552
 553         router = batadv_orig_router_get(orig_node, recv_if);
 554
 555         if (!router)
 556                 return router;
 557
 558         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 559          * and if activated.
 560          */
 561         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 562                 return router;
 563
 564         /* bonding: loop through the list of possible routers found
 565          * for the various outgoing interfaces and find a candidate after
 566          * the last chosen bonding candidate (next_candidate). If no such
 567          * router is found, use the first candidate found (the previously
 568          * chosen bonding candidate might have been the last one in the list).
 569          * If this can't be found either, return the previously chosen
 570          * router - obviously there are no other candidates.
 571          */
 572         rcu_read_lock();
 573         last_candidate = batadv_last_bonding_get(orig_node);
 574         if (last_candidate)
 575                 last_cand_router = rcu_dereference(last_candidate->router);
 576
 577         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 578                 /* acquire some structures and references ... */
 579                 if (!kref_get_unless_zero(&cand->refcount))
 580                         continue;
 581
 582                 cand_router = rcu_dereference(cand->router);
 583                 if (!cand_router)
 584                         goto next;
 585
 586                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 587                         cand_router = NULL;
 588                         goto next;
 589                 }
 590
 591                 /* alternative candidate should be good enough to be
 592                  * considered
 593                  */
 594                 if (!bao->neigh.is_similar_or_better(cand_router,
 595                                                      cand->if_outgoing, router,
 596                                                      recv_if))
 597                         goto next;
 598
 599                 /* don't use the same router twice */
 600                 if (last_cand_router == cand_router)
 601                         goto next;
 602
 603                 /* mark the first possible candidate */
 604                 if (!first_candidate) {
 605                         kref_get(&cand_router->refcount);
 606                         kref_get(&cand->refcount);
 607                         first_candidate = cand;
 608                         first_candidate_router = cand_router;
 609                 }
 610
 611                 /* check if the loop has already passed the previously selected
 612                  * candidate ... this function should select the next candidate
 613                  * AFTER the previously used bonding candidate.
 614                  */
 615                 if (!last_candidate || last_candidate_found) {
 616                         next_candidate = cand;
 617                         next_candidate_router = cand_router;
 618                         break;
 619                 }
 620
 621                 if (last_candidate == cand)
 622                         last_candidate_found = true;
 623 next:
 624                 /* free references */
 625                 if (cand_router) {
 626                         batadv_neigh_node_put(cand_router);
 627                         cand_router = NULL;
 628                 }
 629                 batadv_orig_ifinfo_put(cand);
 630         }
 631         rcu_read_unlock();
 632
 633         /* After finding candidates, handle the three cases:
 634          * 1) there is a next candidate, use that
 635          * 2) there is no next candidate, use the first of the list
 636          * 3) there is no candidate at all, return the default router
 637          */
 638         if (next_candidate) {
 639                 batadv_neigh_node_put(router);
 640
 641                 kref_get(&next_candidate_router->refcount);
 642                 router = next_candidate_router;
 643                 batadv_last_bonding_replace(orig_node, next_candidate);
 644         } else if (first_candidate) {
 645                 batadv_neigh_node_put(router);
 646
 647                 kref_get(&first_candidate_router->refcount);
 648                 router = first_candidate_router;
 649                 batadv_last_bonding_replace(orig_node, first_candidate);
 650         } else {
 651                 batadv_last_bonding_replace(orig_node, NULL);
 652         }
 653
 654         /* cleanup of candidates */
 655         if (first_candidate) {
 656                 batadv_neigh_node_put(first_candidate_router);
 657                 batadv_orig_ifinfo_put(first_candidate);
 658         }
 659
 660         if (next_candidate) {
 661                 batadv_neigh_node_put(next_candidate_router);
 662                 batadv_orig_ifinfo_put(next_candidate);
 663         }
 664
 665         if (last_candidate)
 666                 batadv_orig_ifinfo_put(last_candidate);
 667
 668         return router;
 669 }
 670
 671 static int batadv_route_unicast_packet(struct sk_buff *skb,
 672                                        struct batadv_hard_iface *recv_if)
 673 {
 674         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 675         struct batadv_orig_node *orig_node = NULL;
 676         struct batadv_unicast_packet *unicast_packet;
 677         struct ethhdr *ethhdr = eth_hdr(skb);
 678         int res, hdr_len, ret = NET_RX_DROP;
 679         unsigned int len;
 680
 681         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 682
 683         /* TTL exceeded */
 684         if (unicast_packet->ttl < 2) {
 685                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 686                          ethhdr->h_source, unicast_packet->dest);
 687                 goto free_skb;
 688         }
 689
 690         /* get routing information */
 691         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 692
 693         if (!orig_node)
 694                 goto free_skb;
 695
 696         /* create a copy of the skb, if needed, to modify it. */
 697         if (skb_cow(skb, ETH_HLEN) < 0)
 698                 goto put_orig_node;
 699
 700         /* decrement ttl */
 701         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 702         unicast_packet->ttl--;
 703
 704         switch (unicast_packet->packet_type) {
 705         case BATADV_UNICAST_4ADDR:
 706                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 707                 break;
 708         case BATADV_UNICAST:
 709                 hdr_len = sizeof(struct batadv_unicast_packet);
 710                 break;
 711         default:
 712                 /* other packet types not supported - yet */
 713                 hdr_len = -1;
 714                 break;
 715         }
 716
 717         if (hdr_len > 0)
 718                 batadv_skb_set_priority(skb, hdr_len);
 719
 720         len = skb->len;
 721         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 722         if (res == NET_XMIT_SUCCESS)
 723                 ret = NET_RX_SUCCESS;
 724
 725         /* skb was consumed */
 726         skb = NULL;
 727
 728         /* translate transmit result into receive result */
 729         if (res == NET_XMIT_SUCCESS) {
 730                 /* skb was transmitted and consumed */
 731                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 732                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 733                                    len + ETH_HLEN);
 734         }
 735
 736 put_orig_node:
 737         batadv_orig_node_put(orig_node);
 738 free_skb:
 739         kfree_skb(skb);
 740
 741         return ret;
 742 }
 743
 744 /**
 745  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 746  * @bat_priv: the bat priv with all the soft interface information
 747  * @unicast_packet: the unicast header to be updated
 748  * @dst_addr: the payload destination
 749  * @vid: VLAN identifier
 750  *
 751  * Search the translation table for dst_addr and update the unicast header with
 752  * the new corresponding information (originator address where the destination
 753  * client currently is and its known TTVN)
 754  *
 755  * Return: true if the packet header has been updated, false otherwise
 756  */
 757 static bool
 758 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 759                               struct batadv_unicast_packet *unicast_packet,
 760                               u8 *dst_addr, unsigned short vid)
 761 {
 762         struct batadv_orig_node *orig_node = NULL;
 763         struct batadv_hard_iface *primary_if = NULL;
 764         bool ret = false;
 765         u8 *orig_addr, orig_ttvn;
 766
 767         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 768                 primary_if = batadv_primary_if_get_selected(bat_priv);
 769                 if (!primary_if)
 770                         goto out;
 771                 orig_addr = primary_if->net_dev->dev_addr;
 772                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 773         } else {
 774                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 775                                                      vid);
 776                 if (!orig_node)
 777                         goto out;
 778
 779                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 780                         goto out;
 781
 782                 orig_addr = orig_node->orig;
 783                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 784         }
 785
 786         /* update the packet header */
 787         ether_addr_copy(unicast_packet->dest, orig_addr);
 788         unicast_packet->ttvn = orig_ttvn;
 789
 790         ret = true;
 791 out:
 792         if (primary_if)
 793                 batadv_hardif_put(primary_if);
 794         if (orig_node)
 795                 batadv_orig_node_put(orig_node);
 796
 797         return ret;
 798 }
 799
 800 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 801                                       struct sk_buff *skb, int hdr_len)
 802 {
 803         struct batadv_unicast_packet *unicast_packet;
 804         struct batadv_hard_iface *primary_if;
 805         struct batadv_orig_node *orig_node;
 806         u8 curr_ttvn, old_ttvn;
 807         struct ethhdr *ethhdr;
 808         unsigned short vid;
 809         int is_old_ttvn;
 810
 811         /* check if there is enough data before accessing it */
 812         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 813                 return false;
 814
 815         /* create a copy of the skb (in case of for re-routing) to modify it. */
 816         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 817                 return false;
 818
 819         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 820         vid = batadv_get_vid(skb, hdr_len);
 821         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 822
 823         /* check if the destination client was served by this node and it is now
 824          * roaming. In this case, it means that the node has got a ROAM_ADV
 825          * message and that it knows the new destination in the mesh to re-route
 826          * the packet to
 827          */
 828         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 829                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 830                                                   ethhdr->h_dest, vid))
 831                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 832                                                bat_priv,
 833                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 834                                                unicast_packet->dest,
 835                                                ethhdr->h_dest);
 836                 /* at this point the mesh destination should have been
 837                  * substituted with the originator address found in the global
 838                  * table. If not, let the packet go untouched anyway because
 839                  * there is nothing the node can do
 840                  */
 841                 return true;
 842         }
 843
 844         /* retrieve the TTVN known by this node for the packet destination. This
 845          * value is used later to check if the node which sent (or re-routed
 846          * last time) the packet had an updated information or not
 847          */
 848         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 849         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 850                 orig_node = batadv_orig_hash_find(bat_priv,
 851                                                   unicast_packet->dest);
 852                 /* if it is not possible to find the orig_node representing the
 853                  * destination, the packet can immediately be dropped as it will
 854                  * not be possible to deliver it
 855                  */
 856                 if (!orig_node)
 857                         return false;
 858
 859                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 860                 batadv_orig_node_put(orig_node);
 861         }
 862
 863         /* check if the TTVN contained in the packet is fresher than what the
 864          * node knows
 865          */
 866         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 867         if (!is_old_ttvn)
 868                 return true;
 869
 870         old_ttvn = unicast_packet->ttvn;
 871         /* the packet was forged based on outdated network information. Its
 872          * destination can possibly be updated and forwarded towards the new
 873          * target host
 874          */
 875         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 876                                           ethhdr->h_dest, vid)) {
 877                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 878                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 879                                        unicast_packet->dest, ethhdr->h_dest,
 880                                        old_ttvn, curr_ttvn);
 881                 return true;
 882         }
 883
 884         /* the packet has not been re-routed: either the destination is
 885          * currently served by this node or there is no destination at all and
 886          * it is possible to drop the packet
 887          */
 888         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 889                 return false;
 890
 891         /* update the header in order to let the packet be delivered to this
 892          * node's soft interface
 893          */
 894         primary_if = batadv_primary_if_get_selected(bat_priv);
 895         if (!primary_if)
 896                 return false;
 897
 898         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 899
 900         batadv_hardif_put(primary_if);
 901
 902         unicast_packet->ttvn = curr_ttvn;
 903
 904         return true;
 905 }
 906
 907 /**
 908  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 909  *      are in the unicast number space but not yet known to the implementation
 910  * @skb: unicast tvlv packet to process
 911  * @recv_if: pointer to interface this packet was received on
 912  *
 913  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 914  * otherwise.
 915  */
 916 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 917                                          struct batadv_hard_iface *recv_if)
 918 {
 919         struct batadv_unicast_packet *unicast_packet;
 920         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 921         int check, hdr_size = sizeof(*unicast_packet);
 922
 923         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 924         if (check < 0)
 925                 goto free_skb;
 926
 927         /* we don't know about this type, drop it. */
 928         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 929         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 930                 goto free_skb;
 931
 932         return batadv_route_unicast_packet(skb, recv_if);
 933
 934 free_skb:
 935         kfree_skb(skb);
 936         return NET_RX_DROP;
 937 }
 938
 939 int batadv_recv_unicast_packet(struct sk_buff *skb,
 940                                struct batadv_hard_iface *recv_if)
 941 {
 942         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 943         struct batadv_unicast_packet *unicast_packet;
 944         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 945         u8 *orig_addr;
 946         struct batadv_orig_node *orig_node = NULL;
 947         int check, hdr_size = sizeof(*unicast_packet);
 948         enum batadv_subtype subtype;
 949         bool is4addr;
 950         int ret = NET_RX_DROP;
 951
 952         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 953         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 954
 955         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 956         /* the caller function should have already pulled 2 bytes */
 957         if (is4addr)
 958                 hdr_size = sizeof(*unicast_4addr_packet);
 959
 960         /* function returns -EREMOTE for promiscuous packets */
 961         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 962
 963         /* Even though the packet is not for us, we might save it to use for
 964          * decoding a later received coded packet
 965          */
 966         if (check == -EREMOTE)
 967                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 968
 969         if (check < 0)
 970                 goto free_skb;
 971         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 972                 goto free_skb;
 973
 974         /* packet for me */
 975         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 976                 if (is4addr) {
 977                         subtype = unicast_4addr_packet->subtype;
 978                         batadv_dat_inc_counter(bat_priv, subtype);
 979
 980                         /* Only payload data should be considered for speedy
 981                          * join. For example, DAT also uses unicast 4addr
 982                          * types, but those packets should not be considered
 983                          * for speedy join, since the clients do not actually
 984                          * reside at the sending originator.
 985                          */
 986                         if (subtype == BATADV_P_DATA) {
 987                                 orig_addr = unicast_4addr_packet->src;
 988                                 orig_node = batadv_orig_hash_find(bat_priv,
 989                                                                   orig_addr);
 990                         }
 991                 }
 992
 993                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 994                                                           hdr_size))
 995                         goto rx_success;
 996                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 997                                                         hdr_size))
 998                         goto rx_success;
 999
1000                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
1001                                     orig_node);
1002
1003 rx_success:
1004                 if (orig_node)
1005                         batadv_orig_node_put(orig_node);
1006
1007                 return NET_RX_SUCCESS;
1008         }
1009
1010         ret = batadv_route_unicast_packet(skb, recv_if);
1011         /* skb was consumed */
1012         skb = NULL;
1013
1014 free_skb:
1015         kfree_skb(skb);
1016
1017         return ret;
1018 }
1019
1020 /**
1021  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
1022  * @skb: unicast tvlv packet to process
1023  * @recv_if: pointer to interface this packet was received on
1024  *
1025  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1026  * otherwise.
1027  */
1028 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1029                              struct batadv_hard_iface *recv_if)
1030 {
1031         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1032         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1033         unsigned char *tvlv_buff;
1034         u16 tvlv_buff_len;
1035         int hdr_size = sizeof(*unicast_tvlv_packet);
1036         int ret = NET_RX_DROP;
1037
1038         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1039                 goto free_skb;
1040
1041         /* the header is likely to be modified while forwarding */
1042         if (skb_cow(skb, hdr_size) < 0)
1043                 goto free_skb;
1044
1045         /* packet needs to be linearized to access the tvlv content */
1046         if (skb_linearize(skb) < 0)
1047                 goto free_skb;
1048
1049         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1050
1051         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1052         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1053
1054         if (tvlv_buff_len > skb->len - hdr_size)
1055                 goto free_skb;
1056
1057         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1058                                              unicast_tvlv_packet->src,
1059                                              unicast_tvlv_packet->dst,
1060                                              tvlv_buff, tvlv_buff_len);
1061
1062         if (ret != NET_RX_SUCCESS) {
1063                 ret = batadv_route_unicast_packet(skb, recv_if);
1064                 /* skb was consumed */
1065                 skb = NULL;
1066         }
1067
1068 free_skb:
1069         kfree_skb(skb);
1070
1071         return ret;
1072 }
1073
1074 /**
1075  * batadv_recv_frag_packet - process received fragment
1076  * @skb: the received fragment
1077  * @recv_if: interface that the skb is received on
1078  *
1079  * This function does one of the three following things: 1) Forward fragment, if
1080  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1081  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1082  *
1083  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1084  */
1085 int batadv_recv_frag_packet(struct sk_buff *skb,
1086                             struct batadv_hard_iface *recv_if)
1087 {
1088         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1089         struct batadv_orig_node *orig_node_src = NULL;
1090         struct batadv_frag_packet *frag_packet;
1091         int ret = NET_RX_DROP;
1092
1093         if (batadv_check_unicast_packet(bat_priv, skb,
1094                                         sizeof(*frag_packet)) < 0)
1095                 goto free_skb;
1096
1097         frag_packet = (struct batadv_frag_packet *)skb->data;
1098         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1099         if (!orig_node_src)
1100                 goto free_skb;
1101
1102         skb->priority = frag_packet->priority + 256;
1103
1104         /* Route the fragment if it is not for us and too big to be merged. */
1105         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1106             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1107                 /* skb was consumed */
1108                 skb = NULL;
1109                 ret = NET_RX_SUCCESS;
1110                 goto put_orig_node;
1111         }
1112
1113         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1114         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1115
1116         /* Add fragment to buffer and merge if possible. */
1117         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1118                 goto put_orig_node;
1119
1120         /* Deliver merged packet to the appropriate handler, if it was
1121          * merged
1122          */
1123         if (skb) {
1124                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1125                                        &recv_if->batman_adv_ptype, NULL);
1126                 /* skb was consumed */
1127                 skb = NULL;
1128         }
1129
1130         ret = NET_RX_SUCCESS;
1131
1132 put_orig_node:
1133         batadv_orig_node_put(orig_node_src);
1134 free_skb:
1135         kfree_skb(skb);
1136
1137         return ret;
1138 }
1139
1140 int batadv_recv_bcast_packet(struct sk_buff *skb,
1141                              struct batadv_hard_iface *recv_if)
1142 {
1143         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1144         struct batadv_orig_node *orig_node = NULL;
1145         struct batadv_bcast_packet *bcast_packet;
1146         struct ethhdr *ethhdr;
1147         int hdr_size = sizeof(*bcast_packet);
1148         int ret = NET_RX_DROP;
1149         s32 seq_diff;
1150         u32 seqno;
1151
1152         /* drop packet if it has not necessary minimum size */
1153         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1154                 goto free_skb;
1155
1156         ethhdr = eth_hdr(skb);
1157
1158         /* packet with broadcast indication but unicast recipient */
1159         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1160                 goto free_skb;
1161
1162         /* packet with broadcast/multicast sender address */
1163         if (is_multicast_ether_addr(ethhdr->h_source))
1164                 goto free_skb;
1165
1166         /* ignore broadcasts sent by myself */
1167         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1168                 goto free_skb;
1169
1170         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1171
1172         /* ignore broadcasts originated by myself */
1173         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1174                 goto free_skb;
1175
1176         if (bcast_packet->ttl < 2)
1177                 goto free_skb;
1178
1179         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1180
1181         if (!orig_node)
1182                 goto free_skb;
1183
1184         spin_lock_bh(&orig_node->bcast_seqno_lock);
1185
1186         seqno = ntohl(bcast_packet->seqno);
1187         /* check whether the packet is a duplicate */
1188         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1189                             seqno))
1190                 goto spin_unlock;
1191
1192         seq_diff = seqno - orig_node->last_bcast_seqno;
1193
1194         /* check whether the packet is old and the host just restarted. */
1195         if (batadv_window_protected(bat_priv, seq_diff,
1196                                     BATADV_BCAST_MAX_AGE,
1197                                     &orig_node->bcast_seqno_reset, NULL))
1198                 goto spin_unlock;
1199
1200         /* mark broadcast in flood history, update window position
1201          * if required.
1202          */
1203         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1204                 orig_node->last_bcast_seqno = seqno;
1205
1206         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1207
1208         /* check whether this has been sent by another originator before */
1209         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1210                 goto free_skb;
1211
1212         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1213
1214         /* rebroadcast packet */
1215         batadv_add_bcast_packet_to_list(bat_priv, skb, 1, false);
1216
1217         /* don't hand the broadcast up if it is from an originator
1218          * from the same backbone.
1219          */
1220         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1221                 goto free_skb;
1222
1223         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1224                 goto rx_success;
1225         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1226                 goto rx_success;
1227
1228         /* broadcast for me */
1229         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1230
1231 rx_success:
1232         ret = NET_RX_SUCCESS;
1233         goto out;
1234
1235 spin_unlock:
1236         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1237 free_skb:
1238         kfree_skb(skb);
1239 out:
1240         if (orig_node)
1241                 batadv_orig_node_put(orig_node);
1242         return ret;
1243 }