kernel/net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2015 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "routing.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/printk.h>
  30 #include <linux/rculist.h>
  31 #include <linux/rcupdate.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/stddef.h>
  35
  36 #include "bitarray.h"
  37 #include "bridge_loop_avoidance.h"
  38 #include "distributed-arp-table.h"
  39 #include "fragmentation.h"
  40 #include "hard-interface.h"
  41 #include "icmp_socket.h"
  42 #include "network-coding.h"
  43 #include "originator.h"
  44 #include "packet.h"
  45 #include "send.h"
  46 #include "soft-interface.h"
  47 #include "translation-table.h"
  48
  49 static int batadv_route_unicast_packet(struct sk_buff *skb,
  50                                        struct batadv_hard_iface *recv_if);
  51
  52 /**
  53  * _batadv_update_route - set the router for this originator
  54  * @bat_priv: the bat priv with all the soft interface information
  55  * @orig_node: orig node which is to be configured
  56  * @recv_if: the receive interface for which this route is set
  57  * @neigh_node: neighbor which should be the next router
  58  *
  59  * This function does not perform any error checks
  60  */
  61 static void _batadv_update_route(struct batadv_priv *bat_priv,
  62                                  struct batadv_orig_node *orig_node,
  63                                  struct batadv_hard_iface *recv_if,
  64                                  struct batadv_neigh_node *neigh_node)
  65 {
  66         struct batadv_orig_ifinfo *orig_ifinfo;
  67         struct batadv_neigh_node *curr_router;
  68
  69         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  70         if (!orig_ifinfo)
  71                 return;
  72
  73         rcu_read_lock();
  74         curr_router = rcu_dereference(orig_ifinfo->router);
  75         if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
  76                 curr_router = NULL;
  77         rcu_read_unlock();
  78
  79         /* route deleted */
  80         if ((curr_router) && (!neigh_node)) {
  81                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  82                            "Deleting route towards: %pM\n", orig_node->orig);
  83                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  84                                           "Deleted route towards originator");
  85
  86         /* route added */
  87         } else if ((!curr_router) && (neigh_node)) {
  88                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  89                            "Adding route towards: %pM (via %pM)\n",
  90                            orig_node->orig, neigh_node->addr);
  91         /* route changed */
  92         } else if (neigh_node && curr_router) {
  93                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  94                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  95                            orig_node->orig, neigh_node->addr,
  96                            curr_router->addr);
  97         }
  98
  99         if (curr_router)
 100                 batadv_neigh_node_free_ref(curr_router);
 101
 102         /* increase refcount of new best neighbor */
 103         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
 104                 neigh_node = NULL;
 105
 106         spin_lock_bh(&orig_node->neigh_list_lock);
 107         /* curr_router used earlier may not be the current orig_ifinfo->router
 108          * anymore because it was dereferenced outside of the neigh_list_lock
 109          * protected region. After the new best neighbor has replace the current
 110          * best neighbor the reference counter needs to decrease. Consequently,
 111          * the code needs to ensure the curr_router variable contains a pointer
 112          * to the replaced best neighbor.
 113          */
 114         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 115
 116         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 117         spin_unlock_bh(&orig_node->neigh_list_lock);
 118         batadv_orig_ifinfo_free_ref(orig_ifinfo);
 119
 120         /* decrease refcount of previous best neighbor */
 121         if (curr_router)
 122                 batadv_neigh_node_free_ref(curr_router);
 123 }
 124
 125 /**
 126  * batadv_update_route - set the router for this originator
 127  * @bat_priv: the bat priv with all the soft interface information
 128  * @orig_node: orig node which is to be configured
 129  * @recv_if: the receive interface for which this route is set
 130  * @neigh_node: neighbor which should be the next router
 131  */
 132 void batadv_update_route(struct batadv_priv *bat_priv,
 133                          struct batadv_orig_node *orig_node,
 134                          struct batadv_hard_iface *recv_if,
 135                          struct batadv_neigh_node *neigh_node)
 136 {
 137         struct batadv_neigh_node *router = NULL;
 138
 139         if (!orig_node)
 140                 goto out;
 141
 142         router = batadv_orig_router_get(orig_node, recv_if);
 143
 144         if (router != neigh_node)
 145                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 146
 147 out:
 148         if (router)
 149                 batadv_neigh_node_free_ref(router);
 150 }
 151
 152 /* checks whether the host restarted and is in the protection time.
 153  * returns:
 154  *  0 if the packet is to be accepted
 155  *  1 if the packet is to be ignored.
 156  */
 157 int batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 158                             unsigned long *last_reset)
 159 {
 160         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 161             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 162                 if (!batadv_has_timed_out(*last_reset,
 163                                           BATADV_RESET_PROTECTION_MS))
 164                         return 1;
 165
 166                 *last_reset = jiffies;
 167                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 168                            "old packet received, start protection\n");
 169         }
 170
 171         return 0;
 172 }
 173
 174 bool batadv_check_management_packet(struct sk_buff *skb,
 175                                     struct batadv_hard_iface *hard_iface,
 176                                     int header_len)
 177 {
 178         struct ethhdr *ethhdr;
 179
 180         /* drop packet if it has not necessary minimum size */
 181         if (unlikely(!pskb_may_pull(skb, header_len)))
 182                 return false;
 183
 184         ethhdr = eth_hdr(skb);
 185
 186         /* packet with broadcast indication but unicast recipient */
 187         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 188                 return false;
 189
 190         /* packet with broadcast sender address */
 191         if (is_broadcast_ether_addr(ethhdr->h_source))
 192                 return false;
 193
 194         /* create a copy of the skb, if needed, to modify it. */
 195         if (skb_cow(skb, 0) < 0)
 196                 return false;
 197
 198         /* keep skb linear */
 199         if (skb_linearize(skb) < 0)
 200                 return false;
 201
 202         return true;
 203 }
 204
 205 /**
 206  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 207  * @bat_priv: the bat priv with all the soft interface information
 208  * @skb: icmp packet to process
 209  *
 210  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 211  * otherwise.
 212  */
 213 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 214                                       struct sk_buff *skb)
 215 {
 216         struct batadv_hard_iface *primary_if = NULL;
 217         struct batadv_orig_node *orig_node = NULL;
 218         struct batadv_icmp_header *icmph;
 219         int res, ret = NET_RX_DROP;
 220
 221         icmph = (struct batadv_icmp_header *)skb->data;
 222
 223         switch (icmph->msg_type) {
 224         case BATADV_ECHO_REPLY:
 225         case BATADV_DESTINATION_UNREACHABLE:
 226         case BATADV_TTL_EXCEEDED:
 227                 /* receive the packet */
 228                 if (skb_linearize(skb) < 0)
 229                         break;
 230
 231                 batadv_socket_receive_packet(icmph, skb->len);
 232                 break;
 233         case BATADV_ECHO_REQUEST:
 234                 /* answer echo request (ping) */
 235                 primary_if = batadv_primary_if_get_selected(bat_priv);
 236                 if (!primary_if)
 237                         goto out;
 238
 239                 /* get routing information */
 240                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 241                 if (!orig_node)
 242                         goto out;
 243
 244                 /* create a copy of the skb, if needed, to modify it. */
 245                 if (skb_cow(skb, ETH_HLEN) < 0)
 246                         goto out;
 247
 248                 icmph = (struct batadv_icmp_header *)skb->data;
 249
 250                 ether_addr_copy(icmph->dst, icmph->orig);
 251                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 252                 icmph->msg_type = BATADV_ECHO_REPLY;
 253                 icmph->ttl = BATADV_TTL;
 254
 255                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 256                 if (res != NET_XMIT_DROP)
 257                         ret = NET_RX_SUCCESS;
 258
 259                 break;
 260         default:
 261                 /* drop unknown type */
 262                 goto out;
 263         }
 264 out:
 265         if (primary_if)
 266                 batadv_hardif_free_ref(primary_if);
 267         if (orig_node)
 268                 batadv_orig_node_free_ref(orig_node);
 269         return ret;
 270 }
 271
 272 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 273                                          struct sk_buff *skb)
 274 {
 275         struct batadv_hard_iface *primary_if = NULL;
 276         struct batadv_orig_node *orig_node = NULL;
 277         struct batadv_icmp_packet *icmp_packet;
 278         int ret = NET_RX_DROP;
 279
 280         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 281
 282         /* send TTL exceeded if packet is an echo request (traceroute) */
 283         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 284                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 285                          icmp_packet->orig, icmp_packet->dst);
 286                 goto out;
 287         }
 288
 289         primary_if = batadv_primary_if_get_selected(bat_priv);
 290         if (!primary_if)
 291                 goto out;
 292
 293         /* get routing information */
 294         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 295         if (!orig_node)
 296                 goto out;
 297
 298         /* create a copy of the skb, if needed, to modify it. */
 299         if (skb_cow(skb, ETH_HLEN) < 0)
 300                 goto out;
 301
 302         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 303
 304         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 305         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 306         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 307         icmp_packet->ttl = BATADV_TTL;
 308
 309         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 310                 ret = NET_RX_SUCCESS;
 311
 312 out:
 313         if (primary_if)
 314                 batadv_hardif_free_ref(primary_if);
 315         if (orig_node)
 316                 batadv_orig_node_free_ref(orig_node);
 317         return ret;
 318 }
 319
 320 int batadv_recv_icmp_packet(struct sk_buff *skb,
 321                             struct batadv_hard_iface *recv_if)
 322 {
 323         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 324         struct batadv_icmp_header *icmph;
 325         struct batadv_icmp_packet_rr *icmp_packet_rr;
 326         struct ethhdr *ethhdr;
 327         struct batadv_orig_node *orig_node = NULL;
 328         int hdr_size = sizeof(struct batadv_icmp_header);
 329         int ret = NET_RX_DROP;
 330
 331         /* drop packet if it has not necessary minimum size */
 332         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 333                 goto out;
 334
 335         ethhdr = eth_hdr(skb);
 336
 337         /* packet with unicast indication but broadcast recipient */
 338         if (is_broadcast_ether_addr(ethhdr->h_dest))
 339                 goto out;
 340
 341         /* packet with broadcast sender address */
 342         if (is_broadcast_ether_addr(ethhdr->h_source))
 343                 goto out;
 344
 345         /* not for me */
 346         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 347                 goto out;
 348
 349         icmph = (struct batadv_icmp_header *)skb->data;
 350
 351         /* add record route information if not full */
 352         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 353              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 354             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 355                 if (skb_linearize(skb) < 0)
 356                         goto out;
 357
 358                 /* create a copy of the skb, if needed, to modify it. */
 359                 if (skb_cow(skb, ETH_HLEN) < 0)
 360                         goto out;
 361
 362                 icmph = (struct batadv_icmp_header *)skb->data;
 363                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 364                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 365                         goto out;
 366
 367                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 368                                 ethhdr->h_dest);
 369                 icmp_packet_rr->rr_cur++;
 370         }
 371
 372         /* packet for me */
 373         if (batadv_is_my_mac(bat_priv, icmph->dst))
 374                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 375
 376         /* TTL exceeded */
 377         if (icmph->ttl < 2)
 378                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 379
 380         /* get routing information */
 381         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 382         if (!orig_node)
 383                 goto out;
 384
 385         /* create a copy of the skb, if needed, to modify it. */
 386         if (skb_cow(skb, ETH_HLEN) < 0)
 387                 goto out;
 388
 389         icmph = (struct batadv_icmp_header *)skb->data;
 390
 391         /* decrement ttl */
 392         icmph->ttl--;
 393
 394         /* route it */
 395         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 396                 ret = NET_RX_SUCCESS;
 397
 398 out:
 399         if (orig_node)
 400                 batadv_orig_node_free_ref(orig_node);
 401         return ret;
 402 }
 403
 404 /**
 405  * batadv_check_unicast_packet - Check for malformed unicast packets
 406  * @bat_priv: the bat priv with all the soft interface information
 407  * @skb: packet to check
 408  * @hdr_size: size of header to pull
 409  *
 410  * Check for short header and bad addresses in given packet. Returns negative
 411  * value when check fails and 0 otherwise. The negative value depends on the
 412  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 413  * and -EREMOTE for non-local (other host) destination.
 414  */
 415 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 416                                        struct sk_buff *skb, int hdr_size)
 417 {
 418         struct ethhdr *ethhdr;
 419
 420         /* drop packet if it has not necessary minimum size */
 421         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 422                 return -ENODATA;
 423
 424         ethhdr = eth_hdr(skb);
 425
 426         /* packet with unicast indication but broadcast recipient */
 427         if (is_broadcast_ether_addr(ethhdr->h_dest))
 428                 return -EBADR;
 429
 430         /* packet with broadcast sender address */
 431         if (is_broadcast_ether_addr(ethhdr->h_source))
 432                 return -EBADR;
 433
 434         /* not for me */
 435         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 436                 return -EREMOTE;
 437
 438         return 0;
 439 }
 440
 441 /**
 442  * batadv_find_router - find a suitable router for this originator
 443  * @bat_priv: the bat priv with all the soft interface information
 444  * @orig_node: the destination node
 445  * @recv_if: pointer to interface this packet was received on
 446  *
 447  * Returns the router which should be used for this orig_node on
 448  * this interface, or NULL if not available.
 449  */
 450 struct batadv_neigh_node *
 451 batadv_find_router(struct batadv_priv *bat_priv,
 452                    struct batadv_orig_node *orig_node,
 453                    struct batadv_hard_iface *recv_if)
 454 {
 455         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 456         struct batadv_neigh_node *first_candidate_router = NULL;
 457         struct batadv_neigh_node *next_candidate_router = NULL;
 458         struct batadv_neigh_node *router, *cand_router = NULL;
 459         struct batadv_neigh_node *last_cand_router = NULL;
 460         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 461         struct batadv_orig_ifinfo *next_candidate = NULL;
 462         struct batadv_orig_ifinfo *last_candidate;
 463         bool last_candidate_found = false;
 464
 465         if (!orig_node)
 466                 return NULL;
 467
 468         router = batadv_orig_router_get(orig_node, recv_if);
 469
 470         if (!router)
 471                 return router;
 472
 473         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 474          * and if activated.
 475          */
 476         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 477                 return router;
 478
 479         /* bonding: loop through the list of possible routers found
 480          * for the various outgoing interfaces and find a candidate after
 481          * the last chosen bonding candidate (next_candidate). If no such
 482          * router is found, use the first candidate found (the previously
 483          * chosen bonding candidate might have been the last one in the list).
 484          * If this can't be found either, return the previously chosen
 485          * router - obviously there are no other candidates.
 486          */
 487         rcu_read_lock();
 488         last_candidate = orig_node->last_bonding_candidate;
 489         if (last_candidate)
 490                 last_cand_router = rcu_dereference(last_candidate->router);
 491
 492         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 493                 /* acquire some structures and references ... */
 494                 if (!atomic_inc_not_zero(&cand->refcount))
 495                         continue;
 496
 497                 cand_router = rcu_dereference(cand->router);
 498                 if (!cand_router)
 499                         goto next;
 500
 501                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 502                         cand_router = NULL;
 503                         goto next;
 504                 }
 505
 506                 /* alternative candidate should be good enough to be
 507                  * considered
 508                  */
 509                 if (!bao->bat_neigh_is_equiv_or_better(cand_router,
 510                                                        cand->if_outgoing,
 511                                                        router, recv_if))
 512                         goto next;
 513
 514                 /* don't use the same router twice */
 515                 if (last_cand_router == cand_router)
 516                         goto next;
 517
 518                 /* mark the first possible candidate */
 519                 if (!first_candidate) {
 520                         atomic_inc(&cand_router->refcount);
 521                         atomic_inc(&cand->refcount);
 522                         first_candidate = cand;
 523                         first_candidate_router = cand_router;
 524                 }
 525
 526                 /* check if the loop has already passed the previously selected
 527                  * candidate ... this function should select the next candidate
 528                  * AFTER the previously used bonding candidate.
 529                  */
 530                 if (!last_candidate || last_candidate_found) {
 531                         next_candidate = cand;
 532                         next_candidate_router = cand_router;
 533                         break;
 534                 }
 535
 536                 if (last_candidate == cand)
 537                         last_candidate_found = true;
 538 next:
 539                 /* free references */
 540                 if (cand_router) {
 541                         batadv_neigh_node_free_ref(cand_router);
 542                         cand_router = NULL;
 543                 }
 544                 batadv_orig_ifinfo_free_ref(cand);
 545         }
 546         rcu_read_unlock();
 547
 548         /* last_bonding_candidate is reset below, remove the old reference. */
 549         if (orig_node->last_bonding_candidate)
 550                 batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
 551
 552         /* After finding candidates, handle the three cases:
 553          * 1) there is a next candidate, use that
 554          * 2) there is no next candidate, use the first of the list
 555          * 3) there is no candidate at all, return the default router
 556          */
 557         if (next_candidate) {
 558                 batadv_neigh_node_free_ref(router);
 559
 560                 /* remove references to first candidate, we don't need it. */
 561                 if (first_candidate) {
 562                         batadv_neigh_node_free_ref(first_candidate_router);
 563                         batadv_orig_ifinfo_free_ref(first_candidate);
 564                 }
 565                 router = next_candidate_router;
 566                 orig_node->last_bonding_candidate = next_candidate;
 567         } else if (first_candidate) {
 568                 batadv_neigh_node_free_ref(router);
 569
 570                 /* refcounting has already been done in the loop above. */
 571                 router = first_candidate_router;
 572                 orig_node->last_bonding_candidate = first_candidate;
 573         } else {
 574                 orig_node->last_bonding_candidate = NULL;
 575         }
 576
 577         return router;
 578 }
 579
 580 static int batadv_route_unicast_packet(struct sk_buff *skb,
 581                                        struct batadv_hard_iface *recv_if)
 582 {
 583         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 584         struct batadv_orig_node *orig_node = NULL;
 585         struct batadv_unicast_packet *unicast_packet;
 586         struct ethhdr *ethhdr = eth_hdr(skb);
 587         int res, hdr_len, ret = NET_RX_DROP;
 588
 589         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 590
 591         /* TTL exceeded */
 592         if (unicast_packet->ttl < 2) {
 593                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 594                          ethhdr->h_source, unicast_packet->dest);
 595                 goto out;
 596         }
 597
 598         /* get routing information */
 599         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 600
 601         if (!orig_node)
 602                 goto out;
 603
 604         /* create a copy of the skb, if needed, to modify it. */
 605         if (skb_cow(skb, ETH_HLEN) < 0)
 606                 goto out;
 607
 608         /* decrement ttl */
 609         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 610         unicast_packet->ttl--;
 611
 612         switch (unicast_packet->packet_type) {
 613         case BATADV_UNICAST_4ADDR:
 614                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 615                 break;
 616         case BATADV_UNICAST:
 617                 hdr_len = sizeof(struct batadv_unicast_packet);
 618                 break;
 619         default:
 620                 /* other packet types not supported - yet */
 621                 hdr_len = -1;
 622                 break;
 623         }
 624
 625         if (hdr_len > 0)
 626                 batadv_skb_set_priority(skb, hdr_len);
 627
 628         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 629
 630         /* translate transmit result into receive result */
 631         if (res == NET_XMIT_SUCCESS) {
 632                 /* skb was transmitted and consumed */
 633                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 634                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 635                                    skb->len + ETH_HLEN);
 636
 637                 ret = NET_RX_SUCCESS;
 638         } else if (res == NET_XMIT_POLICED) {
 639                 /* skb was buffered and consumed */
 640                 ret = NET_RX_SUCCESS;
 641         }
 642
 643 out:
 644         if (orig_node)
 645                 batadv_orig_node_free_ref(orig_node);
 646         return ret;
 647 }
 648
 649 /**
 650  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 651  * @bat_priv: the bat priv with all the soft interface information
 652  * @unicast_packet: the unicast header to be updated
 653  * @dst_addr: the payload destination
 654  * @vid: VLAN identifier
 655  *
 656  * Search the translation table for dst_addr and update the unicast header with
 657  * the new corresponding information (originator address where the destination
 658  * client currently is and its known TTVN)
 659  *
 660  * Returns true if the packet header has been updated, false otherwise
 661  */
 662 static bool
 663 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 664                               struct batadv_unicast_packet *unicast_packet,
 665                               u8 *dst_addr, unsigned short vid)
 666 {
 667         struct batadv_orig_node *orig_node = NULL;
 668         struct batadv_hard_iface *primary_if = NULL;
 669         bool ret = false;
 670         u8 *orig_addr, orig_ttvn;
 671
 672         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 673                 primary_if = batadv_primary_if_get_selected(bat_priv);
 674                 if (!primary_if)
 675                         goto out;
 676                 orig_addr = primary_if->net_dev->dev_addr;
 677                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 678         } else {
 679                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 680                                                      vid);
 681                 if (!orig_node)
 682                         goto out;
 683
 684                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 685                         goto out;
 686
 687                 orig_addr = orig_node->orig;
 688                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 689         }
 690
 691         /* update the packet header */
 692         ether_addr_copy(unicast_packet->dest, orig_addr);
 693         unicast_packet->ttvn = orig_ttvn;
 694
 695         ret = true;
 696 out:
 697         if (primary_if)
 698                 batadv_hardif_free_ref(primary_if);
 699         if (orig_node)
 700                 batadv_orig_node_free_ref(orig_node);
 701
 702         return ret;
 703 }
 704
 705 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 706                                      struct sk_buff *skb, int hdr_len) {
 707         struct batadv_unicast_packet *unicast_packet;
 708         struct batadv_hard_iface *primary_if;
 709         struct batadv_orig_node *orig_node;
 710         u8 curr_ttvn, old_ttvn;
 711         struct ethhdr *ethhdr;
 712         unsigned short vid;
 713         int is_old_ttvn;
 714
 715         /* check if there is enough data before accessing it */
 716         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 717                 return 0;
 718
 719         /* create a copy of the skb (in case of for re-routing) to modify it. */
 720         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 721                 return 0;
 722
 723         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 724         vid = batadv_get_vid(skb, hdr_len);
 725         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 726
 727         /* check if the destination client was served by this node and it is now
 728          * roaming. In this case, it means that the node has got a ROAM_ADV
 729          * message and that it knows the new destination in the mesh to re-route
 730          * the packet to
 731          */
 732         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 733                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 734                                                   ethhdr->h_dest, vid))
 735                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 736                                                bat_priv,
 737                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 738                                                unicast_packet->dest,
 739                                                ethhdr->h_dest);
 740                 /* at this point the mesh destination should have been
 741                  * substituted with the originator address found in the global
 742                  * table. If not, let the packet go untouched anyway because
 743                  * there is nothing the node can do
 744                  */
 745                 return 1;
 746         }
 747
 748         /* retrieve the TTVN known by this node for the packet destination. This
 749          * value is used later to check if the node which sent (or re-routed
 750          * last time) the packet had an updated information or not
 751          */
 752         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 753         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 754                 orig_node = batadv_orig_hash_find(bat_priv,
 755                                                   unicast_packet->dest);
 756                 /* if it is not possible to find the orig_node representing the
 757                  * destination, the packet can immediately be dropped as it will
 758                  * not be possible to deliver it
 759                  */
 760                 if (!orig_node)
 761                         return 0;
 762
 763                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 764                 batadv_orig_node_free_ref(orig_node);
 765         }
 766
 767         /* check if the TTVN contained in the packet is fresher than what the
 768          * node knows
 769          */
 770         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 771         if (!is_old_ttvn)
 772                 return 1;
 773
 774         old_ttvn = unicast_packet->ttvn;
 775         /* the packet was forged based on outdated network information. Its
 776          * destination can possibly be updated and forwarded towards the new
 777          * target host
 778          */
 779         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 780                                           ethhdr->h_dest, vid)) {
 781                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 782                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 783                                        unicast_packet->dest, ethhdr->h_dest,
 784                                        old_ttvn, curr_ttvn);
 785                 return 1;
 786         }
 787
 788         /* the packet has not been re-routed: either the destination is
 789          * currently served by this node or there is no destination at all and
 790          * it is possible to drop the packet
 791          */
 792         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 793                 return 0;
 794
 795         /* update the header in order to let the packet be delivered to this
 796          * node's soft interface
 797          */
 798         primary_if = batadv_primary_if_get_selected(bat_priv);
 799         if (!primary_if)
 800                 return 0;
 801
 802         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 803
 804         batadv_hardif_free_ref(primary_if);
 805
 806         unicast_packet->ttvn = curr_ttvn;
 807
 808         return 1;
 809 }
 810
 811 /**
 812  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 813  *      are in the unicast number space but not yet known to the implementation
 814  * @skb: unicast tvlv packet to process
 815  * @recv_if: pointer to interface this packet was received on
 816  *
 817  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 818  * otherwise.
 819  */
 820 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 821                                          struct batadv_hard_iface *recv_if)
 822 {
 823         struct batadv_unicast_packet *unicast_packet;
 824         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 825         int check, hdr_size = sizeof(*unicast_packet);
 826
 827         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 828         if (check < 0)
 829                 return NET_RX_DROP;
 830
 831         /* we don't know about this type, drop it. */
 832         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 833         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 834                 return NET_RX_DROP;
 835
 836         return batadv_route_unicast_packet(skb, recv_if);
 837 }
 838
 839 int batadv_recv_unicast_packet(struct sk_buff *skb,
 840                                struct batadv_hard_iface *recv_if)
 841 {
 842         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 843         struct batadv_unicast_packet *unicast_packet;
 844         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 845         u8 *orig_addr;
 846         struct batadv_orig_node *orig_node = NULL;
 847         int check, hdr_size = sizeof(*unicast_packet);
 848         enum batadv_subtype subtype;
 849         bool is4addr;
 850
 851         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 852         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 853
 854         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 855         /* the caller function should have already pulled 2 bytes */
 856         if (is4addr)
 857                 hdr_size = sizeof(*unicast_4addr_packet);
 858
 859         /* function returns -EREMOTE for promiscuous packets */
 860         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 861
 862         /* Even though the packet is not for us, we might save it to use for
 863          * decoding a later received coded packet
 864          */
 865         if (check == -EREMOTE)
 866                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 867
 868         if (check < 0)
 869                 return NET_RX_DROP;
 870         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 871                 return NET_RX_DROP;
 872
 873         /* packet for me */
 874         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 875                 if (is4addr) {
 876                         subtype = unicast_4addr_packet->subtype;
 877                         batadv_dat_inc_counter(bat_priv, subtype);
 878
 879                         /* Only payload data should be considered for speedy
 880                          * join. For example, DAT also uses unicast 4addr
 881                          * types, but those packets should not be considered
 882                          * for speedy join, since the clients do not actually
 883                          * reside at the sending originator.
 884                          */
 885                         if (subtype == BATADV_P_DATA) {
 886                                 orig_addr = unicast_4addr_packet->src;
 887                                 orig_node = batadv_orig_hash_find(bat_priv,
 888                                                                   orig_addr);
 889                         }
 890                 }
 891
 892                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 893                                                           hdr_size))
 894                         goto rx_success;
 895                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 896                                                         hdr_size))
 897                         goto rx_success;
 898
 899                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 900                                     orig_node);
 901
 902 rx_success:
 903                 if (orig_node)
 904                         batadv_orig_node_free_ref(orig_node);
 905
 906                 return NET_RX_SUCCESS;
 907         }
 908
 909         return batadv_route_unicast_packet(skb, recv_if);
 910 }
 911
 912 /**
 913  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 914  * @skb: unicast tvlv packet to process
 915  * @recv_if: pointer to interface this packet was received on
 916  * @dst_addr: the payload destination
 917  *
 918  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 919  * otherwise.
 920  */
 921 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 922                              struct batadv_hard_iface *recv_if)
 923 {
 924         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 925         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 926         unsigned char *tvlv_buff;
 927         u16 tvlv_buff_len;
 928         int hdr_size = sizeof(*unicast_tvlv_packet);
 929         int ret = NET_RX_DROP;
 930
 931         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 932                 return NET_RX_DROP;
 933
 934         /* the header is likely to be modified while forwarding */
 935         if (skb_cow(skb, hdr_size) < 0)
 936                 return NET_RX_DROP;
 937
 938         /* packet needs to be linearized to access the tvlv content */
 939         if (skb_linearize(skb) < 0)
 940                 return NET_RX_DROP;
 941
 942         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 943
 944         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 945         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 946
 947         if (tvlv_buff_len > skb->len - hdr_size)
 948                 return NET_RX_DROP;
 949
 950         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 951                                              unicast_tvlv_packet->src,
 952                                              unicast_tvlv_packet->dst,
 953                                              tvlv_buff, tvlv_buff_len);
 954
 955         if (ret != NET_RX_SUCCESS)
 956                 ret = batadv_route_unicast_packet(skb, recv_if);
 957         else
 958                 consume_skb(skb);
 959
 960         return ret;
 961 }
 962
 963 /**
 964  * batadv_recv_frag_packet - process received fragment
 965  * @skb: the received fragment
 966  * @recv_if: interface that the skb is received on
 967  *
 968  * This function does one of the three following things: 1) Forward fragment, if
 969  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 970  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 971  *
 972  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 973  */
 974 int batadv_recv_frag_packet(struct sk_buff *skb,
 975                             struct batadv_hard_iface *recv_if)
 976 {
 977         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 978         struct batadv_orig_node *orig_node_src = NULL;
 979         struct batadv_frag_packet *frag_packet;
 980         int ret = NET_RX_DROP;
 981
 982         if (batadv_check_unicast_packet(bat_priv, skb,
 983                                         sizeof(*frag_packet)) < 0)
 984                 goto out;
 985
 986         frag_packet = (struct batadv_frag_packet *)skb->data;
 987         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 988         if (!orig_node_src)
 989                 goto out;
 990
 991         /* Route the fragment if it is not for us and too big to be merged. */
 992         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 993             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 994                 ret = NET_RX_SUCCESS;
 995                 goto out;
 996         }
 997
 998         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
 999         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1000
1001         /* Add fragment to buffer and merge if possible. */
1002         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1003                 goto out;
1004
1005         /* Deliver merged packet to the appropriate handler, if it was
1006          * merged
1007          */
1008         if (skb)
1009                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1010                                        &recv_if->batman_adv_ptype, NULL);
1011
1012         ret = NET_RX_SUCCESS;
1013
1014 out:
1015         if (orig_node_src)
1016                 batadv_orig_node_free_ref(orig_node_src);
1017
1018         return ret;
1019 }
1020
1021 int batadv_recv_bcast_packet(struct sk_buff *skb,
1022                              struct batadv_hard_iface *recv_if)
1023 {
1024         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1025         struct batadv_orig_node *orig_node = NULL;
1026         struct batadv_bcast_packet *bcast_packet;
1027         struct ethhdr *ethhdr;
1028         int hdr_size = sizeof(*bcast_packet);
1029         int ret = NET_RX_DROP;
1030         s32 seq_diff;
1031         u32 seqno;
1032
1033         /* drop packet if it has not necessary minimum size */
1034         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1035                 goto out;
1036
1037         ethhdr = eth_hdr(skb);
1038
1039         /* packet with broadcast indication but unicast recipient */
1040         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1041                 goto out;
1042
1043         /* packet with broadcast sender address */
1044         if (is_broadcast_ether_addr(ethhdr->h_source))
1045                 goto out;
1046
1047         /* ignore broadcasts sent by myself */
1048         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1049                 goto out;
1050
1051         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1052
1053         /* ignore broadcasts originated by myself */
1054         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1055                 goto out;
1056
1057         if (bcast_packet->ttl < 2)
1058                 goto out;
1059
1060         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1061
1062         if (!orig_node)
1063                 goto out;
1064
1065         spin_lock_bh(&orig_node->bcast_seqno_lock);
1066
1067         seqno = ntohl(bcast_packet->seqno);
1068         /* check whether the packet is a duplicate */
1069         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1070                             seqno))
1071                 goto spin_unlock;
1072
1073         seq_diff = seqno - orig_node->last_bcast_seqno;
1074
1075         /* check whether the packet is old and the host just restarted. */
1076         if (batadv_window_protected(bat_priv, seq_diff,
1077                                     &orig_node->bcast_seqno_reset))
1078                 goto spin_unlock;
1079
1080         /* mark broadcast in flood history, update window position
1081          * if required.
1082          */
1083         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1084                 orig_node->last_bcast_seqno = seqno;
1085
1086         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1087
1088         /* check whether this has been sent by another originator before */
1089         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1090                 goto out;
1091
1092         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1093
1094         /* rebroadcast packet */
1095         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1096
1097         /* don't hand the broadcast up if it is from an originator
1098          * from the same backbone.
1099          */
1100         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1101                 goto out;
1102
1103         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1104                 goto rx_success;
1105         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1106                 goto rx_success;
1107
1108         /* broadcast for me */
1109         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1110                             orig_node);
1111
1112 rx_success:
1113         ret = NET_RX_SUCCESS;
1114         goto out;
1115
1116 spin_unlock:
1117         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1118 out:
1119         if (orig_node)
1120                 batadv_orig_node_free_ref(orig_node);
1121         return ret;
1122 }