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