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 /**
 144  * batadv_window_protected - checks whether the host restarted and is in the
 145  *  protection time.
 146  * @bat_priv: the bat priv with all the soft interface information
 147  * @seq_num_diff: difference between the current/received sequence number and
 148  *  the last sequence number
 149  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 150  *  is detected
 151  *
 152  * Return:
 153  *  0 if the packet is to be accepted.
 154  *  1 if the packet is to be ignored.
 155  */
 156 int batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 157                             unsigned long *last_reset)
 158 {
 159         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 160             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 161                 if (!batadv_has_timed_out(*last_reset,
 162                                           BATADV_RESET_PROTECTION_MS))
 163                         return 1;
 164
 165                 *last_reset = jiffies;
 166                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 167                            "old packet received, start protection\n");
 168         }
 169
 170         return 0;
 171 }
 172
 173 bool batadv_check_management_packet(struct sk_buff *skb,
 174                                     struct batadv_hard_iface *hard_iface,
 175                                     int header_len)
 176 {
 177         struct ethhdr *ethhdr;
 178
 179         /* drop packet if it has not necessary minimum size */
 180         if (unlikely(!pskb_may_pull(skb, header_len)))
 181                 return false;
 182
 183         ethhdr = eth_hdr(skb);
 184
 185         /* packet with broadcast indication but unicast recipient */
 186         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 187                 return false;
 188
 189         /* packet with broadcast sender address */
 190         if (is_broadcast_ether_addr(ethhdr->h_source))
 191                 return false;
 192
 193         /* create a copy of the skb, if needed, to modify it. */
 194         if (skb_cow(skb, 0) < 0)
 195                 return false;
 196
 197         /* keep skb linear */
 198         if (skb_linearize(skb) < 0)
 199                 return false;
 200
 201         return true;
 202 }
 203
 204 /**
 205  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 206  * @bat_priv: the bat priv with all the soft interface information
 207  * @skb: icmp packet to process
 208  *
 209  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 210  * otherwise.
 211  */
 212 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 213                                       struct sk_buff *skb)
 214 {
 215         struct batadv_hard_iface *primary_if = NULL;
 216         struct batadv_orig_node *orig_node = NULL;
 217         struct batadv_icmp_header *icmph;
 218         int res, ret = NET_RX_DROP;
 219
 220         icmph = (struct batadv_icmp_header *)skb->data;
 221
 222         switch (icmph->msg_type) {
 223         case BATADV_ECHO_REPLY:
 224         case BATADV_DESTINATION_UNREACHABLE:
 225         case BATADV_TTL_EXCEEDED:
 226                 /* receive the packet */
 227                 if (skb_linearize(skb) < 0)
 228                         break;
 229
 230                 batadv_socket_receive_packet(icmph, skb->len);
 231                 break;
 232         case BATADV_ECHO_REQUEST:
 233                 /* answer echo request (ping) */
 234                 primary_if = batadv_primary_if_get_selected(bat_priv);
 235                 if (!primary_if)
 236                         goto out;
 237
 238                 /* get routing information */
 239                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 240                 if (!orig_node)
 241                         goto out;
 242
 243                 /* create a copy of the skb, if needed, to modify it. */
 244                 if (skb_cow(skb, ETH_HLEN) < 0)
 245                         goto out;
 246
 247                 icmph = (struct batadv_icmp_header *)skb->data;
 248
 249                 ether_addr_copy(icmph->dst, icmph->orig);
 250                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 251                 icmph->msg_type = BATADV_ECHO_REPLY;
 252                 icmph->ttl = BATADV_TTL;
 253
 254                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 255                 if (res != NET_XMIT_DROP)
 256                         ret = NET_RX_SUCCESS;
 257
 258                 break;
 259         default:
 260                 /* drop unknown type */
 261                 goto out;
 262         }
 263 out:
 264         if (primary_if)
 265                 batadv_hardif_free_ref(primary_if);
 266         if (orig_node)
 267                 batadv_orig_node_free_ref(orig_node);
 268         return ret;
 269 }
 270
 271 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 272                                          struct sk_buff *skb)
 273 {
 274         struct batadv_hard_iface *primary_if = NULL;
 275         struct batadv_orig_node *orig_node = NULL;
 276         struct batadv_icmp_packet *icmp_packet;
 277         int ret = NET_RX_DROP;
 278
 279         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 280
 281         /* send TTL exceeded if packet is an echo request (traceroute) */
 282         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 283                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 284                          icmp_packet->orig, icmp_packet->dst);
 285                 goto out;
 286         }
 287
 288         primary_if = batadv_primary_if_get_selected(bat_priv);
 289         if (!primary_if)
 290                 goto out;
 291
 292         /* get routing information */
 293         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 294         if (!orig_node)
 295                 goto out;
 296
 297         /* create a copy of the skb, if needed, to modify it. */
 298         if (skb_cow(skb, ETH_HLEN) < 0)
 299                 goto out;
 300
 301         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 302
 303         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 304         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 305         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 306         icmp_packet->ttl = BATADV_TTL;
 307
 308         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 309                 ret = NET_RX_SUCCESS;
 310
 311 out:
 312         if (primary_if)
 313                 batadv_hardif_free_ref(primary_if);
 314         if (orig_node)
 315                 batadv_orig_node_free_ref(orig_node);
 316         return ret;
 317 }
 318
 319 int batadv_recv_icmp_packet(struct sk_buff *skb,
 320                             struct batadv_hard_iface *recv_if)
 321 {
 322         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 323         struct batadv_icmp_header *icmph;
 324         struct batadv_icmp_packet_rr *icmp_packet_rr;
 325         struct ethhdr *ethhdr;
 326         struct batadv_orig_node *orig_node = NULL;
 327         int hdr_size = sizeof(struct batadv_icmp_header);
 328         int ret = NET_RX_DROP;
 329
 330         /* drop packet if it has not necessary minimum size */
 331         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 332                 goto out;
 333
 334         ethhdr = eth_hdr(skb);
 335
 336         /* packet with unicast indication but broadcast recipient */
 337         if (is_broadcast_ether_addr(ethhdr->h_dest))
 338                 goto out;
 339
 340         /* packet with broadcast sender address */
 341         if (is_broadcast_ether_addr(ethhdr->h_source))
 342                 goto out;
 343
 344         /* not for me */
 345         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 346                 goto out;
 347
 348         icmph = (struct batadv_icmp_header *)skb->data;
 349
 350         /* add record route information if not full */
 351         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 352              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 353             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 354                 if (skb_linearize(skb) < 0)
 355                         goto out;
 356
 357                 /* create a copy of the skb, if needed, to modify it. */
 358                 if (skb_cow(skb, ETH_HLEN) < 0)
 359                         goto out;
 360
 361                 icmph = (struct batadv_icmp_header *)skb->data;
 362                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 363                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 364                         goto out;
 365
 366                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 367                                 ethhdr->h_dest);
 368                 icmp_packet_rr->rr_cur++;
 369         }
 370
 371         /* packet for me */
 372         if (batadv_is_my_mac(bat_priv, icmph->dst))
 373                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 374
 375         /* TTL exceeded */
 376         if (icmph->ttl < 2)
 377                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 378
 379         /* get routing information */
 380         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 381         if (!orig_node)
 382                 goto out;
 383
 384         /* create a copy of the skb, if needed, to modify it. */
 385         if (skb_cow(skb, ETH_HLEN) < 0)
 386                 goto out;
 387
 388         icmph = (struct batadv_icmp_header *)skb->data;
 389
 390         /* decrement ttl */
 391         icmph->ttl--;
 392
 393         /* route it */
 394         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 395                 ret = NET_RX_SUCCESS;
 396
 397 out:
 398         if (orig_node)
 399                 batadv_orig_node_free_ref(orig_node);
 400         return ret;
 401 }
 402
 403 /**
 404  * batadv_check_unicast_packet - Check for malformed unicast packets
 405  * @bat_priv: the bat priv with all the soft interface information
 406  * @skb: packet to check
 407  * @hdr_size: size of header to pull
 408  *
 409  * Check for short header and bad addresses in given packet.
 410  *
 411  * Return: negative value when check fails and 0 otherwise. The negative value
 412  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 413  * destination or source, 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  * Return: 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_similar_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  * Return: 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  * Return: 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  *
 917  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 918  * otherwise.
 919  */
 920 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 921                              struct batadv_hard_iface *recv_if)
 922 {
 923         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 924         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 925         unsigned char *tvlv_buff;
 926         u16 tvlv_buff_len;
 927         int hdr_size = sizeof(*unicast_tvlv_packet);
 928         int ret = NET_RX_DROP;
 929
 930         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 931                 return NET_RX_DROP;
 932
 933         /* the header is likely to be modified while forwarding */
 934         if (skb_cow(skb, hdr_size) < 0)
 935                 return NET_RX_DROP;
 936
 937         /* packet needs to be linearized to access the tvlv content */
 938         if (skb_linearize(skb) < 0)
 939                 return NET_RX_DROP;
 940
 941         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 942
 943         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 944         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 945
 946         if (tvlv_buff_len > skb->len - hdr_size)
 947                 return NET_RX_DROP;
 948
 949         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 950                                              unicast_tvlv_packet->src,
 951                                              unicast_tvlv_packet->dst,
 952                                              tvlv_buff, tvlv_buff_len);
 953
 954         if (ret != NET_RX_SUCCESS)
 955                 ret = batadv_route_unicast_packet(skb, recv_if);
 956         else
 957                 consume_skb(skb);
 958
 959         return ret;
 960 }
 961
 962 /**
 963  * batadv_recv_frag_packet - process received fragment
 964  * @skb: the received fragment
 965  * @recv_if: interface that the skb is received on
 966  *
 967  * This function does one of the three following things: 1) Forward fragment, if
 968  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 969  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 970  *
 971  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 972  */
 973 int batadv_recv_frag_packet(struct sk_buff *skb,
 974                             struct batadv_hard_iface *recv_if)
 975 {
 976         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 977         struct batadv_orig_node *orig_node_src = NULL;
 978         struct batadv_frag_packet *frag_packet;
 979         int ret = NET_RX_DROP;
 980
 981         if (batadv_check_unicast_packet(bat_priv, skb,
 982                                         sizeof(*frag_packet)) < 0)
 983                 goto out;
 984
 985         frag_packet = (struct batadv_frag_packet *)skb->data;
 986         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 987         if (!orig_node_src)
 988                 goto out;
 989
 990         /* Route the fragment if it is not for us and too big to be merged. */
 991         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 992             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 993                 ret = NET_RX_SUCCESS;
 994                 goto out;
 995         }
 996
 997         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
 998         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
 999
1000         /* Add fragment to buffer and merge if possible. */
1001         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1002                 goto out;
1003
1004         /* Deliver merged packet to the appropriate handler, if it was
1005          * merged
1006          */
1007         if (skb)
1008                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1009                                        &recv_if->batman_adv_ptype, NULL);
1010
1011         ret = NET_RX_SUCCESS;
1012
1013 out:
1014         if (orig_node_src)
1015                 batadv_orig_node_free_ref(orig_node_src);
1016
1017         return ret;
1018 }
1019
1020 int batadv_recv_bcast_packet(struct sk_buff *skb,
1021                              struct batadv_hard_iface *recv_if)
1022 {
1023         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1024         struct batadv_orig_node *orig_node = NULL;
1025         struct batadv_bcast_packet *bcast_packet;
1026         struct ethhdr *ethhdr;
1027         int hdr_size = sizeof(*bcast_packet);
1028         int ret = NET_RX_DROP;
1029         s32 seq_diff;
1030         u32 seqno;
1031
1032         /* drop packet if it has not necessary minimum size */
1033         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1034                 goto out;
1035
1036         ethhdr = eth_hdr(skb);
1037
1038         /* packet with broadcast indication but unicast recipient */
1039         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1040                 goto out;
1041
1042         /* packet with broadcast sender address */
1043         if (is_broadcast_ether_addr(ethhdr->h_source))
1044                 goto out;
1045
1046         /* ignore broadcasts sent by myself */
1047         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1048                 goto out;
1049
1050         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1051
1052         /* ignore broadcasts originated by myself */
1053         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1054                 goto out;
1055
1056         if (bcast_packet->ttl < 2)
1057                 goto out;
1058
1059         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1060
1061         if (!orig_node)
1062                 goto out;
1063
1064         spin_lock_bh(&orig_node->bcast_seqno_lock);
1065
1066         seqno = ntohl(bcast_packet->seqno);
1067         /* check whether the packet is a duplicate */
1068         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1069                             seqno))
1070                 goto spin_unlock;
1071
1072         seq_diff = seqno - orig_node->last_bcast_seqno;
1073
1074         /* check whether the packet is old and the host just restarted. */
1075         if (batadv_window_protected(bat_priv, seq_diff,
1076                                     &orig_node->bcast_seqno_reset))
1077                 goto spin_unlock;
1078
1079         /* mark broadcast in flood history, update window position
1080          * if required.
1081          */
1082         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1083                 orig_node->last_bcast_seqno = seqno;
1084
1085         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1086
1087         /* check whether this has been sent by another originator before */
1088         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1089                 goto out;
1090
1091         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1092
1093         /* rebroadcast packet */
1094         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1095
1096         /* don't hand the broadcast up if it is from an originator
1097          * from the same backbone.
1098          */
1099         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1100                 goto out;
1101
1102         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1103                 goto rx_success;
1104         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1105                 goto rx_success;
1106
1107         /* broadcast for me */
1108         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1109                             orig_node);
1110
1111 rx_success:
1112         ret = NET_RX_SUCCESS;
1113         goto out;
1114
1115 spin_unlock:
1116         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1117 out:
1118         if (orig_node)
1119                 batadv_orig_node_free_ref(orig_node);
1120         return ret;
1121 }