net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2016  B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "routing.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/kref.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/printk.h>
  31 #include <linux/rculist.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/stddef.h>
  36
  37 #include "bitarray.h"
  38 #include "bridge_loop_avoidance.h"
  39 #include "distributed-arp-table.h"
  40 #include "fragmentation.h"
  41 #include "hard-interface.h"
  42 #include "icmp_socket.h"
  43 #include "network-coding.h"
  44 #include "originator.h"
  45 #include "packet.h"
  46 #include "send.h"
  47 #include "soft-interface.h"
  48 #include "translation-table.h"
  49
  50 static int batadv_route_unicast_packet(struct sk_buff *skb,
  51                                        struct batadv_hard_iface *recv_if);
  52
  53 /**
  54  * _batadv_update_route - set the router for this originator
  55  * @bat_priv: the bat priv with all the soft interface information
  56  * @orig_node: orig node which is to be configured
  57  * @recv_if: the receive interface for which this route is set
  58  * @neigh_node: neighbor which should be the next router
  59  *
  60  * This function does not perform any error checks
  61  */
  62 static void _batadv_update_route(struct batadv_priv *bat_priv,
  63                                  struct batadv_orig_node *orig_node,
  64                                  struct batadv_hard_iface *recv_if,
  65                                  struct batadv_neigh_node *neigh_node)
  66 {
  67         struct batadv_orig_ifinfo *orig_ifinfo;
  68         struct batadv_neigh_node *curr_router;
  69
  70         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  71         if (!orig_ifinfo)
  72                 return;
  73
  74         rcu_read_lock();
  75         curr_router = rcu_dereference(orig_ifinfo->router);
  76         if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
  77                 curr_router = NULL;
  78         rcu_read_unlock();
  79
  80         /* route deleted */
  81         if ((curr_router) && (!neigh_node)) {
  82                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  83                            "Deleting route towards: %pM\n", orig_node->orig);
  84                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  85                                           "Deleted route towards originator");
  86
  87         /* route added */
  88         } else if ((!curr_router) && (neigh_node)) {
  89                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  90                            "Adding route towards: %pM (via %pM)\n",
  91                            orig_node->orig, neigh_node->addr);
  92         /* route changed */
  93         } else if (neigh_node && curr_router) {
  94                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  95                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  96                            orig_node->orig, neigh_node->addr,
  97                            curr_router->addr);
  98         }
  99
 100         if (curr_router)
 101                 batadv_neigh_node_put(curr_router);
 102
 103         spin_lock_bh(&orig_node->neigh_list_lock);
 104         /* curr_router used earlier may not be the current orig_ifinfo->router
 105          * anymore because it was dereferenced outside of the neigh_list_lock
 106          * protected region. After the new best neighbor has replace the current
 107          * best neighbor the reference counter needs to decrease. Consequently,
 108          * the code needs to ensure the curr_router variable contains a pointer
 109          * to the replaced best neighbor.
 110          */
 111         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 112
 113         /* increase refcount of new best neighbor */
 114         if (neigh_node)
 115                 kref_get(&neigh_node->refcount);
 116
 117         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 118         spin_unlock_bh(&orig_node->neigh_list_lock);
 119         batadv_orig_ifinfo_put(orig_ifinfo);
 120
 121         /* decrease refcount of previous best neighbor */
 122         if (curr_router)
 123                 batadv_neigh_node_put(curr_router);
 124 }
 125
 126 /**
 127  * batadv_update_route - set the router for this originator
 128  * @bat_priv: the bat priv with all the soft interface information
 129  * @orig_node: orig node which is to be configured
 130  * @recv_if: the receive interface for which this route is set
 131  * @neigh_node: neighbor which should be the next router
 132  */
 133 void batadv_update_route(struct batadv_priv *bat_priv,
 134                          struct batadv_orig_node *orig_node,
 135                          struct batadv_hard_iface *recv_if,
 136                          struct batadv_neigh_node *neigh_node)
 137 {
 138         struct batadv_neigh_node *router = NULL;
 139
 140         if (!orig_node)
 141                 goto out;
 142
 143         router = batadv_orig_router_get(orig_node, recv_if);
 144
 145         if (router != neigh_node)
 146                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 147
 148 out:
 149         if (router)
 150                 batadv_neigh_node_put(router);
 151 }
 152
 153 /**
 154  * batadv_window_protected - checks whether the host restarted and is in the
 155  *  protection time.
 156  * @bat_priv: the bat priv with all the soft interface information
 157  * @seq_num_diff: difference between the current/received sequence number and
 158  *  the last sequence number
 159  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 160  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 161  *  is detected
 162  * @protection_started: is set to true if the protection window was started,
 163  *   doesn't change otherwise.
 164  *
 165  * Return:
 166  *  false if the packet is to be accepted.
 167  *  true if the packet is to be ignored.
 168  */
 169 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 170                              s32 seq_old_max_diff, unsigned long *last_reset,
 171                              bool *protection_started)
 172 {
 173         if (seq_num_diff <= -seq_old_max_diff ||
 174             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 175                 if (!batadv_has_timed_out(*last_reset,
 176                                           BATADV_RESET_PROTECTION_MS))
 177                         return true;
 178
 179                 *last_reset = jiffies;
 180                 if (protection_started)
 181                         *protection_started = true;
 182                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 183                            "old packet received, start protection\n");
 184         }
 185
 186         return false;
 187 }
 188
 189 bool batadv_check_management_packet(struct sk_buff *skb,
 190                                     struct batadv_hard_iface *hard_iface,
 191                                     int header_len)
 192 {
 193         struct ethhdr *ethhdr;
 194
 195         /* drop packet if it has not necessary minimum size */
 196         if (unlikely(!pskb_may_pull(skb, header_len)))
 197                 return false;
 198
 199         ethhdr = eth_hdr(skb);
 200
 201         /* packet with broadcast indication but unicast recipient */
 202         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 203                 return false;
 204
 205         /* packet with broadcast sender address */
 206         if (is_broadcast_ether_addr(ethhdr->h_source))
 207                 return false;
 208
 209         /* create a copy of the skb, if needed, to modify it. */
 210         if (skb_cow(skb, 0) < 0)
 211                 return false;
 212
 213         /* keep skb linear */
 214         if (skb_linearize(skb) < 0)
 215                 return false;
 216
 217         return true;
 218 }
 219
 220 /**
 221  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 222  * @bat_priv: the bat priv with all the soft interface information
 223  * @skb: icmp packet to process
 224  *
 225  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 226  * otherwise.
 227  */
 228 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 229                                       struct sk_buff *skb)
 230 {
 231         struct batadv_hard_iface *primary_if = NULL;
 232         struct batadv_orig_node *orig_node = NULL;
 233         struct batadv_icmp_header *icmph;
 234         int res, ret = NET_RX_DROP;
 235
 236         icmph = (struct batadv_icmp_header *)skb->data;
 237
 238         switch (icmph->msg_type) {
 239         case BATADV_ECHO_REPLY:
 240         case BATADV_DESTINATION_UNREACHABLE:
 241         case BATADV_TTL_EXCEEDED:
 242                 /* receive the packet */
 243                 if (skb_linearize(skb) < 0)
 244                         break;
 245
 246                 batadv_socket_receive_packet(icmph, skb->len);
 247                 break;
 248         case BATADV_ECHO_REQUEST:
 249                 /* answer echo request (ping) */
 250                 primary_if = batadv_primary_if_get_selected(bat_priv);
 251                 if (!primary_if)
 252                         goto out;
 253
 254                 /* get routing information */
 255                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 256                 if (!orig_node)
 257                         goto out;
 258
 259                 /* create a copy of the skb, if needed, to modify it. */
 260                 if (skb_cow(skb, ETH_HLEN) < 0)
 261                         goto out;
 262
 263                 icmph = (struct batadv_icmp_header *)skb->data;
 264
 265                 ether_addr_copy(icmph->dst, icmph->orig);
 266                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 267                 icmph->msg_type = BATADV_ECHO_REPLY;
 268                 icmph->ttl = BATADV_TTL;
 269
 270                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 271                 if (res != NET_XMIT_DROP)
 272                         ret = NET_RX_SUCCESS;
 273
 274                 break;
 275         default:
 276                 /* drop unknown type */
 277                 goto out;
 278         }
 279 out:
 280         if (primary_if)
 281                 batadv_hardif_put(primary_if);
 282         if (orig_node)
 283                 batadv_orig_node_put(orig_node);
 284         return ret;
 285 }
 286
 287 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 288                                          struct sk_buff *skb)
 289 {
 290         struct batadv_hard_iface *primary_if = NULL;
 291         struct batadv_orig_node *orig_node = NULL;
 292         struct batadv_icmp_packet *icmp_packet;
 293         int ret = NET_RX_DROP;
 294
 295         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 296
 297         /* send TTL exceeded if packet is an echo request (traceroute) */
 298         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 299                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 300                          icmp_packet->orig, icmp_packet->dst);
 301                 goto out;
 302         }
 303
 304         primary_if = batadv_primary_if_get_selected(bat_priv);
 305         if (!primary_if)
 306                 goto out;
 307
 308         /* get routing information */
 309         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 310         if (!orig_node)
 311                 goto out;
 312
 313         /* create a copy of the skb, if needed, to modify it. */
 314         if (skb_cow(skb, ETH_HLEN) < 0)
 315                 goto out;
 316
 317         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 318
 319         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 320         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 321         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 322         icmp_packet->ttl = BATADV_TTL;
 323
 324         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 325                 ret = NET_RX_SUCCESS;
 326
 327 out:
 328         if (primary_if)
 329                 batadv_hardif_put(primary_if);
 330         if (orig_node)
 331                 batadv_orig_node_put(orig_node);
 332         return ret;
 333 }
 334
 335 int batadv_recv_icmp_packet(struct sk_buff *skb,
 336                             struct batadv_hard_iface *recv_if)
 337 {
 338         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 339         struct batadv_icmp_header *icmph;
 340         struct batadv_icmp_packet_rr *icmp_packet_rr;
 341         struct ethhdr *ethhdr;
 342         struct batadv_orig_node *orig_node = NULL;
 343         int hdr_size = sizeof(struct batadv_icmp_header);
 344         int ret = NET_RX_DROP;
 345
 346         /* drop packet if it has not necessary minimum size */
 347         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 348                 goto out;
 349
 350         ethhdr = eth_hdr(skb);
 351
 352         /* packet with unicast indication but broadcast recipient */
 353         if (is_broadcast_ether_addr(ethhdr->h_dest))
 354                 goto out;
 355
 356         /* packet with broadcast sender address */
 357         if (is_broadcast_ether_addr(ethhdr->h_source))
 358                 goto out;
 359
 360         /* not for me */
 361         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 362                 goto out;
 363
 364         icmph = (struct batadv_icmp_header *)skb->data;
 365
 366         /* add record route information if not full */
 367         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 368              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 369             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 370                 if (skb_linearize(skb) < 0)
 371                         goto out;
 372
 373                 /* create a copy of the skb, if needed, to modify it. */
 374                 if (skb_cow(skb, ETH_HLEN) < 0)
 375                         goto out;
 376
 377                 ethhdr = eth_hdr(skb);
 378                 icmph = (struct batadv_icmp_header *)skb->data;
 379                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 380                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 381                         goto out;
 382
 383                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 384                                 ethhdr->h_dest);
 385                 icmp_packet_rr->rr_cur++;
 386         }
 387
 388         /* packet for me */
 389         if (batadv_is_my_mac(bat_priv, icmph->dst))
 390                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 391
 392         /* TTL exceeded */
 393         if (icmph->ttl < 2)
 394                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 395
 396         /* get routing information */
 397         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 398         if (!orig_node)
 399                 goto out;
 400
 401         /* create a copy of the skb, if needed, to modify it. */
 402         if (skb_cow(skb, ETH_HLEN) < 0)
 403                 goto out;
 404
 405         icmph = (struct batadv_icmp_header *)skb->data;
 406
 407         /* decrement ttl */
 408         icmph->ttl--;
 409
 410         /* route it */
 411         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 412                 ret = NET_RX_SUCCESS;
 413
 414 out:
 415         if (orig_node)
 416                 batadv_orig_node_put(orig_node);
 417         return ret;
 418 }
 419
 420 /**
 421  * batadv_check_unicast_packet - Check for malformed unicast packets
 422  * @bat_priv: the bat priv with all the soft interface information
 423  * @skb: packet to check
 424  * @hdr_size: size of header to pull
 425  *
 426  * Check for short header and bad addresses in given packet.
 427  *
 428  * Return: negative value when check fails and 0 otherwise. The negative value
 429  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 430  * destination or source, and -EREMOTE for non-local (other host) destination.
 431  */
 432 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 433                                        struct sk_buff *skb, int hdr_size)
 434 {
 435         struct ethhdr *ethhdr;
 436
 437         /* drop packet if it has not necessary minimum size */
 438         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 439                 return -ENODATA;
 440
 441         ethhdr = eth_hdr(skb);
 442
 443         /* packet with unicast indication but broadcast recipient */
 444         if (is_broadcast_ether_addr(ethhdr->h_dest))
 445                 return -EBADR;
 446
 447         /* packet with broadcast sender address */
 448         if (is_broadcast_ether_addr(ethhdr->h_source))
 449                 return -EBADR;
 450
 451         /* not for me */
 452         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 453                 return -EREMOTE;
 454
 455         return 0;
 456 }
 457
 458 /**
 459  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 460  * @orig_node: originator node whose bonding candidates should be replaced
 461  * @new_candidate: new bonding candidate or NULL
 462  */
 463 static void
 464 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 465                             struct batadv_orig_ifinfo *new_candidate)
 466 {
 467         struct batadv_orig_ifinfo *old_candidate;
 468
 469         spin_lock_bh(&orig_node->neigh_list_lock);
 470         old_candidate = orig_node->last_bonding_candidate;
 471
 472         if (new_candidate)
 473                 kref_get(&new_candidate->refcount);
 474         orig_node->last_bonding_candidate = new_candidate;
 475         spin_unlock_bh(&orig_node->neigh_list_lock);
 476
 477         if (old_candidate)
 478                 batadv_orig_ifinfo_put(old_candidate);
 479 }
 480
 481 /**
 482  * batadv_find_router - find a suitable router for this originator
 483  * @bat_priv: the bat priv with all the soft interface information
 484  * @orig_node: the destination node
 485  * @recv_if: pointer to interface this packet was received on
 486  *
 487  * Return: the router which should be used for this orig_node on
 488  * this interface, or NULL if not available.
 489  */
 490 struct batadv_neigh_node *
 491 batadv_find_router(struct batadv_priv *bat_priv,
 492                    struct batadv_orig_node *orig_node,
 493                    struct batadv_hard_iface *recv_if)
 494 {
 495         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 496         struct batadv_neigh_node *first_candidate_router = NULL;
 497         struct batadv_neigh_node *next_candidate_router = NULL;
 498         struct batadv_neigh_node *router, *cand_router = NULL;
 499         struct batadv_neigh_node *last_cand_router = NULL;
 500         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 501         struct batadv_orig_ifinfo *next_candidate = NULL;
 502         struct batadv_orig_ifinfo *last_candidate;
 503         bool last_candidate_found = false;
 504
 505         if (!orig_node)
 506                 return NULL;
 507
 508         router = batadv_orig_router_get(orig_node, recv_if);
 509
 510         if (!router)
 511                 return router;
 512
 513         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 514          * and if activated.
 515          */
 516         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 517                 return router;
 518
 519         /* bonding: loop through the list of possible routers found
 520          * for the various outgoing interfaces and find a candidate after
 521          * the last chosen bonding candidate (next_candidate). If no such
 522          * router is found, use the first candidate found (the previously
 523          * chosen bonding candidate might have been the last one in the list).
 524          * If this can't be found either, return the previously chosen
 525          * router - obviously there are no other candidates.
 526          */
 527         rcu_read_lock();
 528         last_candidate = orig_node->last_bonding_candidate;
 529         if (last_candidate)
 530                 last_cand_router = rcu_dereference(last_candidate->router);
 531
 532         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 533                 /* acquire some structures and references ... */
 534                 if (!kref_get_unless_zero(&cand->refcount))
 535                         continue;
 536
 537                 cand_router = rcu_dereference(cand->router);
 538                 if (!cand_router)
 539                         goto next;
 540
 541                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 542                         cand_router = NULL;
 543                         goto next;
 544                 }
 545
 546                 /* alternative candidate should be good enough to be
 547                  * considered
 548                  */
 549                 if (!bao->bat_neigh_is_similar_or_better(cand_router,
 550                                                          cand->if_outgoing,
 551                                                          router, recv_if))
 552                         goto next;
 553
 554                 /* don't use the same router twice */
 555                 if (last_cand_router == cand_router)
 556                         goto next;
 557
 558                 /* mark the first possible candidate */
 559                 if (!first_candidate) {
 560                         kref_get(&cand_router->refcount);
 561                         kref_get(&cand->refcount);
 562                         first_candidate = cand;
 563                         first_candidate_router = cand_router;
 564                 }
 565
 566                 /* check if the loop has already passed the previously selected
 567                  * candidate ... this function should select the next candidate
 568                  * AFTER the previously used bonding candidate.
 569                  */
 570                 if (!last_candidate || last_candidate_found) {
 571                         next_candidate = cand;
 572                         next_candidate_router = cand_router;
 573                         break;
 574                 }
 575
 576                 if (last_candidate == cand)
 577                         last_candidate_found = true;
 578 next:
 579                 /* free references */
 580                 if (cand_router) {
 581                         batadv_neigh_node_put(cand_router);
 582                         cand_router = NULL;
 583                 }
 584                 batadv_orig_ifinfo_put(cand);
 585         }
 586         rcu_read_unlock();
 587
 588         /* After finding candidates, handle the three cases:
 589          * 1) there is a next candidate, use that
 590          * 2) there is no next candidate, use the first of the list
 591          * 3) there is no candidate at all, return the default router
 592          */
 593         if (next_candidate) {
 594                 batadv_neigh_node_put(router);
 595
 596                 kref_get(&next_candidate_router->refcount);
 597                 router = next_candidate_router;
 598                 batadv_last_bonding_replace(orig_node, next_candidate);
 599         } else if (first_candidate) {
 600                 batadv_neigh_node_put(router);
 601
 602                 kref_get(&first_candidate_router->refcount);
 603                 router = first_candidate_router;
 604                 batadv_last_bonding_replace(orig_node, first_candidate);
 605         } else {
 606                 batadv_last_bonding_replace(orig_node, NULL);
 607         }
 608
 609         /* cleanup of candidates */
 610         if (first_candidate) {
 611                 batadv_neigh_node_put(first_candidate_router);
 612                 batadv_orig_ifinfo_put(first_candidate);
 613         }
 614
 615         if (next_candidate) {
 616                 batadv_neigh_node_put(next_candidate_router);
 617                 batadv_orig_ifinfo_put(next_candidate);
 618         }
 619
 620         return router;
 621 }
 622
 623 static int batadv_route_unicast_packet(struct sk_buff *skb,
 624                                        struct batadv_hard_iface *recv_if)
 625 {
 626         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 627         struct batadv_orig_node *orig_node = NULL;
 628         struct batadv_unicast_packet *unicast_packet;
 629         struct ethhdr *ethhdr = eth_hdr(skb);
 630         int res, hdr_len, ret = NET_RX_DROP;
 631         unsigned int len;
 632
 633         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 634
 635         /* TTL exceeded */
 636         if (unicast_packet->ttl < 2) {
 637                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 638                          ethhdr->h_source, unicast_packet->dest);
 639                 goto out;
 640         }
 641
 642         /* get routing information */
 643         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 644
 645         if (!orig_node)
 646                 goto out;
 647
 648         /* create a copy of the skb, if needed, to modify it. */
 649         if (skb_cow(skb, ETH_HLEN) < 0)
 650                 goto out;
 651
 652         /* decrement ttl */
 653         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 654         unicast_packet->ttl--;
 655
 656         switch (unicast_packet->packet_type) {
 657         case BATADV_UNICAST_4ADDR:
 658                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 659                 break;
 660         case BATADV_UNICAST:
 661                 hdr_len = sizeof(struct batadv_unicast_packet);
 662                 break;
 663         default:
 664                 /* other packet types not supported - yet */
 665                 hdr_len = -1;
 666                 break;
 667         }
 668
 669         if (hdr_len > 0)
 670                 batadv_skb_set_priority(skb, hdr_len);
 671
 672         len = skb->len;
 673         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 674
 675         /* translate transmit result into receive result */
 676         if (res == NET_XMIT_SUCCESS) {
 677                 /* skb was transmitted and consumed */
 678                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 679                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 680                                    len + ETH_HLEN);
 681
 682                 ret = NET_RX_SUCCESS;
 683         } else if (res == NET_XMIT_POLICED) {
 684                 /* skb was buffered and consumed */
 685                 ret = NET_RX_SUCCESS;
 686         }
 687
 688 out:
 689         if (orig_node)
 690                 batadv_orig_node_put(orig_node);
 691         return ret;
 692 }
 693
 694 /**
 695  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 696  * @bat_priv: the bat priv with all the soft interface information
 697  * @unicast_packet: the unicast header to be updated
 698  * @dst_addr: the payload destination
 699  * @vid: VLAN identifier
 700  *
 701  * Search the translation table for dst_addr and update the unicast header with
 702  * the new corresponding information (originator address where the destination
 703  * client currently is and its known TTVN)
 704  *
 705  * Return: true if the packet header has been updated, false otherwise
 706  */
 707 static bool
 708 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 709                               struct batadv_unicast_packet *unicast_packet,
 710                               u8 *dst_addr, unsigned short vid)
 711 {
 712         struct batadv_orig_node *orig_node = NULL;
 713         struct batadv_hard_iface *primary_if = NULL;
 714         bool ret = false;
 715         u8 *orig_addr, orig_ttvn;
 716
 717         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 718                 primary_if = batadv_primary_if_get_selected(bat_priv);
 719                 if (!primary_if)
 720                         goto out;
 721                 orig_addr = primary_if->net_dev->dev_addr;
 722                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 723         } else {
 724                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 725                                                      vid);
 726                 if (!orig_node)
 727                         goto out;
 728
 729                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 730                         goto out;
 731
 732                 orig_addr = orig_node->orig;
 733                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 734         }
 735
 736         /* update the packet header */
 737         ether_addr_copy(unicast_packet->dest, orig_addr);
 738         unicast_packet->ttvn = orig_ttvn;
 739
 740         ret = true;
 741 out:
 742         if (primary_if)
 743                 batadv_hardif_put(primary_if);
 744         if (orig_node)
 745                 batadv_orig_node_put(orig_node);
 746
 747         return ret;
 748 }
 749
 750 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 751                                       struct sk_buff *skb, int hdr_len)
 752 {
 753         struct batadv_unicast_packet *unicast_packet;
 754         struct batadv_hard_iface *primary_if;
 755         struct batadv_orig_node *orig_node;
 756         u8 curr_ttvn, old_ttvn;
 757         struct ethhdr *ethhdr;
 758         unsigned short vid;
 759         int is_old_ttvn;
 760
 761         /* check if there is enough data before accessing it */
 762         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 763                 return false;
 764
 765         /* create a copy of the skb (in case of for re-routing) to modify it. */
 766         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 767                 return false;
 768
 769         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 770         vid = batadv_get_vid(skb, hdr_len);
 771         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 772
 773         /* check if the destination client was served by this node and it is now
 774          * roaming. In this case, it means that the node has got a ROAM_ADV
 775          * message and that it knows the new destination in the mesh to re-route
 776          * the packet to
 777          */
 778         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 779                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 780                                                   ethhdr->h_dest, vid))
 781                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 782                                                bat_priv,
 783                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 784                                                unicast_packet->dest,
 785                                                ethhdr->h_dest);
 786                 /* at this point the mesh destination should have been
 787                  * substituted with the originator address found in the global
 788                  * table. If not, let the packet go untouched anyway because
 789                  * there is nothing the node can do
 790                  */
 791                 return true;
 792         }
 793
 794         /* retrieve the TTVN known by this node for the packet destination. This
 795          * value is used later to check if the node which sent (or re-routed
 796          * last time) the packet had an updated information or not
 797          */
 798         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 799         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 800                 orig_node = batadv_orig_hash_find(bat_priv,
 801                                                   unicast_packet->dest);
 802                 /* if it is not possible to find the orig_node representing the
 803                  * destination, the packet can immediately be dropped as it will
 804                  * not be possible to deliver it
 805                  */
 806                 if (!orig_node)
 807                         return false;
 808
 809                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 810                 batadv_orig_node_put(orig_node);
 811         }
 812
 813         /* check if the TTVN contained in the packet is fresher than what the
 814          * node knows
 815          */
 816         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 817         if (!is_old_ttvn)
 818                 return true;
 819
 820         old_ttvn = unicast_packet->ttvn;
 821         /* the packet was forged based on outdated network information. Its
 822          * destination can possibly be updated and forwarded towards the new
 823          * target host
 824          */
 825         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 826                                           ethhdr->h_dest, vid)) {
 827                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 828                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 829                                        unicast_packet->dest, ethhdr->h_dest,
 830                                        old_ttvn, curr_ttvn);
 831                 return true;
 832         }
 833
 834         /* the packet has not been re-routed: either the destination is
 835          * currently served by this node or there is no destination at all and
 836          * it is possible to drop the packet
 837          */
 838         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 839                 return false;
 840
 841         /* update the header in order to let the packet be delivered to this
 842          * node's soft interface
 843          */
 844         primary_if = batadv_primary_if_get_selected(bat_priv);
 845         if (!primary_if)
 846                 return false;
 847
 848         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 849
 850         batadv_hardif_put(primary_if);
 851
 852         unicast_packet->ttvn = curr_ttvn;
 853
 854         return true;
 855 }
 856
 857 /**
 858  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 859  *      are in the unicast number space but not yet known to the implementation
 860  * @skb: unicast tvlv packet to process
 861  * @recv_if: pointer to interface this packet was received on
 862  *
 863  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 864  * otherwise.
 865  */
 866 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 867                                          struct batadv_hard_iface *recv_if)
 868 {
 869         struct batadv_unicast_packet *unicast_packet;
 870         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 871         int check, hdr_size = sizeof(*unicast_packet);
 872
 873         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 874         if (check < 0)
 875                 return NET_RX_DROP;
 876
 877         /* we don't know about this type, drop it. */
 878         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 879         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 880                 return NET_RX_DROP;
 881
 882         return batadv_route_unicast_packet(skb, recv_if);
 883 }
 884
 885 int batadv_recv_unicast_packet(struct sk_buff *skb,
 886                                struct batadv_hard_iface *recv_if)
 887 {
 888         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 889         struct batadv_unicast_packet *unicast_packet;
 890         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 891         u8 *orig_addr;
 892         struct batadv_orig_node *orig_node = NULL;
 893         int check, hdr_size = sizeof(*unicast_packet);
 894         enum batadv_subtype subtype;
 895         bool is4addr;
 896
 897         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 898         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 899
 900         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 901         /* the caller function should have already pulled 2 bytes */
 902         if (is4addr)
 903                 hdr_size = sizeof(*unicast_4addr_packet);
 904
 905         /* function returns -EREMOTE for promiscuous packets */
 906         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 907
 908         /* Even though the packet is not for us, we might save it to use for
 909          * decoding a later received coded packet
 910          */
 911         if (check == -EREMOTE)
 912                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 913
 914         if (check < 0)
 915                 return NET_RX_DROP;
 916         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 917                 return NET_RX_DROP;
 918
 919         /* packet for me */
 920         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 921                 if (is4addr) {
 922                         subtype = unicast_4addr_packet->subtype;
 923                         batadv_dat_inc_counter(bat_priv, subtype);
 924
 925                         /* Only payload data should be considered for speedy
 926                          * join. For example, DAT also uses unicast 4addr
 927                          * types, but those packets should not be considered
 928                          * for speedy join, since the clients do not actually
 929                          * reside at the sending originator.
 930                          */
 931                         if (subtype == BATADV_P_DATA) {
 932                                 orig_addr = unicast_4addr_packet->src;
 933                                 orig_node = batadv_orig_hash_find(bat_priv,
 934                                                                   orig_addr);
 935                         }
 936                 }
 937
 938                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 939                                                           hdr_size))
 940                         goto rx_success;
 941                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 942                                                         hdr_size))
 943                         goto rx_success;
 944
 945                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
 946                                     orig_node);
 947
 948 rx_success:
 949                 if (orig_node)
 950                         batadv_orig_node_put(orig_node);
 951
 952                 return NET_RX_SUCCESS;
 953         }
 954
 955         return batadv_route_unicast_packet(skb, recv_if);
 956 }
 957
 958 /**
 959  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 960  * @skb: unicast tvlv packet to process
 961  * @recv_if: pointer to interface this packet was received on
 962  *
 963  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 964  * otherwise.
 965  */
 966 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 967                              struct batadv_hard_iface *recv_if)
 968 {
 969         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 970         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 971         unsigned char *tvlv_buff;
 972         u16 tvlv_buff_len;
 973         int hdr_size = sizeof(*unicast_tvlv_packet);
 974         int ret = NET_RX_DROP;
 975
 976         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 977                 return NET_RX_DROP;
 978
 979         /* the header is likely to be modified while forwarding */
 980         if (skb_cow(skb, hdr_size) < 0)
 981                 return NET_RX_DROP;
 982
 983         /* packet needs to be linearized to access the tvlv content */
 984         if (skb_linearize(skb) < 0)
 985                 return NET_RX_DROP;
 986
 987         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 988
 989         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 990         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 991
 992         if (tvlv_buff_len > skb->len - hdr_size)
 993                 return NET_RX_DROP;
 994
 995         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 996                                              unicast_tvlv_packet->src,
 997                                              unicast_tvlv_packet->dst,
 998                                              tvlv_buff, tvlv_buff_len);
 999
1000         if (ret != NET_RX_SUCCESS)
1001                 ret = batadv_route_unicast_packet(skb, recv_if);
1002         else
1003                 consume_skb(skb);
1004
1005         return ret;
1006 }
1007
1008 /**
1009  * batadv_recv_frag_packet - process received fragment
1010  * @skb: the received fragment
1011  * @recv_if: interface that the skb is received on
1012  *
1013  * This function does one of the three following things: 1) Forward fragment, if
1014  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1015  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1016  *
1017  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1018  */
1019 int batadv_recv_frag_packet(struct sk_buff *skb,
1020                             struct batadv_hard_iface *recv_if)
1021 {
1022         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1023         struct batadv_orig_node *orig_node_src = NULL;
1024         struct batadv_frag_packet *frag_packet;
1025         int ret = NET_RX_DROP;
1026
1027         if (batadv_check_unicast_packet(bat_priv, skb,
1028                                         sizeof(*frag_packet)) < 0)
1029                 goto out;
1030
1031         frag_packet = (struct batadv_frag_packet *)skb->data;
1032         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1033         if (!orig_node_src)
1034                 goto out;
1035
1036         /* Route the fragment if it is not for us and too big to be merged. */
1037         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1038             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1039                 ret = NET_RX_SUCCESS;
1040                 goto out;
1041         }
1042
1043         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1044         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1045
1046         /* Add fragment to buffer and merge if possible. */
1047         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1048                 goto out;
1049
1050         /* Deliver merged packet to the appropriate handler, if it was
1051          * merged
1052          */
1053         if (skb)
1054                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1055                                        &recv_if->batman_adv_ptype, NULL);
1056
1057         ret = NET_RX_SUCCESS;
1058
1059 out:
1060         if (orig_node_src)
1061                 batadv_orig_node_put(orig_node_src);
1062
1063         return ret;
1064 }
1065
1066 int batadv_recv_bcast_packet(struct sk_buff *skb,
1067                              struct batadv_hard_iface *recv_if)
1068 {
1069         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1070         struct batadv_orig_node *orig_node = NULL;
1071         struct batadv_bcast_packet *bcast_packet;
1072         struct ethhdr *ethhdr;
1073         int hdr_size = sizeof(*bcast_packet);
1074         int ret = NET_RX_DROP;
1075         s32 seq_diff;
1076         u32 seqno;
1077
1078         /* drop packet if it has not necessary minimum size */
1079         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1080                 goto out;
1081
1082         ethhdr = eth_hdr(skb);
1083
1084         /* packet with broadcast indication but unicast recipient */
1085         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1086                 goto out;
1087
1088         /* packet with broadcast sender address */
1089         if (is_broadcast_ether_addr(ethhdr->h_source))
1090                 goto out;
1091
1092         /* ignore broadcasts sent by myself */
1093         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1094                 goto out;
1095
1096         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1097
1098         /* ignore broadcasts originated by myself */
1099         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1100                 goto out;
1101
1102         if (bcast_packet->ttl < 2)
1103                 goto out;
1104
1105         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1106
1107         if (!orig_node)
1108                 goto out;
1109
1110         spin_lock_bh(&orig_node->bcast_seqno_lock);
1111
1112         seqno = ntohl(bcast_packet->seqno);
1113         /* check whether the packet is a duplicate */
1114         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1115                             seqno))
1116                 goto spin_unlock;
1117
1118         seq_diff = seqno - orig_node->last_bcast_seqno;
1119
1120         /* check whether the packet is old and the host just restarted. */
1121         if (batadv_window_protected(bat_priv, seq_diff,
1122                                     BATADV_BCAST_MAX_AGE,
1123                                     &orig_node->bcast_seqno_reset, NULL))
1124                 goto spin_unlock;
1125
1126         /* mark broadcast in flood history, update window position
1127          * if required.
1128          */
1129         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1130                 orig_node->last_bcast_seqno = seqno;
1131
1132         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1133
1134         /* check whether this has been sent by another originator before */
1135         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1136                 goto out;
1137
1138         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1139
1140         /* rebroadcast packet */
1141         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1142
1143         /* don't hand the broadcast up if it is from an originator
1144          * from the same backbone.
1145          */
1146         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1147                 goto out;
1148
1149         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1150                 goto rx_success;
1151         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1152                 goto rx_success;
1153
1154         /* broadcast for me */
1155         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1156
1157 rx_success:
1158         ret = NET_RX_SUCCESS;
1159         goto out;
1160
1161 spin_unlock:
1162         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1163 out:
1164         if (orig_node)
1165                 batadv_orig_node_put(orig_node);
1166         return ret;
1167 }