root/net/batman-adv/routing.c

DEFINITIONS

1. _batadv_update_route
2. batadv_update_route
3. batadv_window_protected
4. batadv_check_management_packet
5. batadv_recv_my_icmp_packet
6. batadv_recv_icmp_ttl_exceeded
7. batadv_recv_icmp_packet
8. batadv_check_unicast_packet
9. batadv_last_bonding_get
10. batadv_last_bonding_replace
11. batadv_find_router
12. batadv_route_unicast_packet
13. batadv_reroute_unicast_packet
14. batadv_check_unicast_ttvn
15. batadv_recv_unhandled_unicast_packet
16. batadv_recv_unicast_packet
17. batadv_recv_unicast_tvlv
18. batadv_recv_frag_packet
19. batadv_recv_bcast_packet

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2007-2019  B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  */
   6 
   7 #include "routing.h"
   8 #include "main.h"
   9 
  10 #include <linux/atomic.h>
  11 #include <linux/byteorder/generic.h>
  12 #include <linux/compiler.h>
  13 #include <linux/errno.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/if_ether.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/kref.h>
  18 #include <linux/netdevice.h>
  19 #include <linux/printk.h>
  20 #include <linux/rculist.h>
  21 #include <linux/rcupdate.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/stddef.h>
  25 #include <uapi/linux/batadv_packet.h>
  26 
  27 #include "bitarray.h"
  28 #include "bridge_loop_avoidance.h"
  29 #include "distributed-arp-table.h"
  30 #include "fragmentation.h"
  31 #include "hard-interface.h"
  32 #include "icmp_socket.h"
  33 #include "log.h"
  34 #include "network-coding.h"
  35 #include "originator.h"
  36 #include "send.h"
  37 #include "soft-interface.h"
  38 #include "tp_meter.h"
  39 #include "translation-table.h"
  40 #include "tvlv.h"
  41 
  42 static int batadv_route_unicast_packet(struct sk_buff *skb,
  43                                        struct batadv_hard_iface *recv_if);
  44 
  45 /**
  46  * _batadv_update_route() - set the router for this originator
  47  * @bat_priv: the bat priv with all the soft interface information
  48  * @orig_node: orig node which is to be configured
  49  * @recv_if: the receive interface for which this route is set
  50  * @neigh_node: neighbor which should be the next router
  51  *
  52  * This function does not perform any error checks
  53  */
  54 static void _batadv_update_route(struct batadv_priv *bat_priv,
  55                                  struct batadv_orig_node *orig_node,
  56                                  struct batadv_hard_iface *recv_if,
  57                                  struct batadv_neigh_node *neigh_node)
  58 {
  59         struct batadv_orig_ifinfo *orig_ifinfo;
  60         struct batadv_neigh_node *curr_router;
  61 
  62         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  63         if (!orig_ifinfo)
  64                 return;
  65 
  66         spin_lock_bh(&orig_node->neigh_list_lock);
  67         /* curr_router used earlier may not be the current orig_ifinfo->router
  68          * anymore because it was dereferenced outside of the neigh_list_lock
  69          * protected region. After the new best neighbor has replace the current
  70          * best neighbor the reference counter needs to decrease. Consequently,
  71          * the code needs to ensure the curr_router variable contains a pointer
  72          * to the replaced best neighbor.
  73          */
  74         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
  75 
  76         /* increase refcount of new best neighbor */
  77         if (neigh_node)
  78                 kref_get(&neigh_node->refcount);
  79 
  80         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
  81         spin_unlock_bh(&orig_node->neigh_list_lock);
  82         batadv_orig_ifinfo_put(orig_ifinfo);
  83 
  84         /* route deleted */
  85         if (curr_router && !neigh_node) {
  86                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  87                            "Deleting route towards: %pM\n", orig_node->orig);
  88                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  89                                           "Deleted route towards originator");
  90 
  91         /* route added */
  92         } else if (!curr_router && neigh_node) {
  93                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  94                            "Adding route towards: %pM (via %pM)\n",
  95                            orig_node->orig, neigh_node->addr);
  96         /* route changed */
  97         } else if (neigh_node && curr_router) {
  98                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  99                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
 100                            orig_node->orig, neigh_node->addr,
 101                            curr_router->addr);
 102         }
 103 
 104         /* decrease refcount of previous best neighbor */
 105         if (curr_router)
 106                 batadv_neigh_node_put(curr_router);
 107 }
 108 
 109 /**
 110  * batadv_update_route() - set the router for this originator
 111  * @bat_priv: the bat priv with all the soft interface information
 112  * @orig_node: orig node which is to be configured
 113  * @recv_if: the receive interface for which this route is set
 114  * @neigh_node: neighbor which should be the next router
 115  */
 116 void batadv_update_route(struct batadv_priv *bat_priv,
 117                          struct batadv_orig_node *orig_node,
 118                          struct batadv_hard_iface *recv_if,
 119                          struct batadv_neigh_node *neigh_node)
 120 {
 121         struct batadv_neigh_node *router = NULL;
 122 
 123         if (!orig_node)
 124                 goto out;
 125 
 126         router = batadv_orig_router_get(orig_node, recv_if);
 127 
 128         if (router != neigh_node)
 129                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 130 
 131 out:
 132         if (router)
 133                 batadv_neigh_node_put(router);
 134 }
 135 
 136 /**
 137  * batadv_window_protected() - checks whether the host restarted and is in the
 138  *  protection time.
 139  * @bat_priv: the bat priv with all the soft interface information
 140  * @seq_num_diff: difference between the current/received sequence number and
 141  *  the last sequence number
 142  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 143  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 144  *  is detected
 145  * @protection_started: is set to true if the protection window was started,
 146  *   doesn't change otherwise.
 147  *
 148  * Return:
 149  *  false if the packet is to be accepted.
 150  *  true if the packet is to be ignored.
 151  */
 152 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 153                              s32 seq_old_max_diff, unsigned long *last_reset,
 154                              bool *protection_started)
 155 {
 156         if (seq_num_diff <= -seq_old_max_diff ||
 157             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 158                 if (!batadv_has_timed_out(*last_reset,
 159                                           BATADV_RESET_PROTECTION_MS))
 160                         return true;
 161 
 162                 *last_reset = jiffies;
 163                 if (protection_started)
 164                         *protection_started = true;
 165                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 166                            "old packet received, start protection\n");
 167         }
 168 
 169         return false;
 170 }
 171 
 172 /**
 173  * batadv_check_management_packet() - Check preconditions for management packets
 174  * @skb: incoming packet buffer
 175  * @hard_iface: incoming hard interface
 176  * @header_len: minimal header length of packet type
 177  *
 178  * Return: true when management preconditions are met, false otherwise
 179  */
 180 bool batadv_check_management_packet(struct sk_buff *skb,
 181                                     struct batadv_hard_iface *hard_iface,
 182                                     int header_len)
 183 {
 184         struct ethhdr *ethhdr;
 185 
 186         /* drop packet if it has not necessary minimum size */
 187         if (unlikely(!pskb_may_pull(skb, header_len)))
 188                 return false;
 189 
 190         ethhdr = eth_hdr(skb);
 191 
 192         /* packet with broadcast indication but unicast recipient */
 193         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 194                 return false;
 195 
 196         /* packet with invalid sender address */
 197         if (!is_valid_ether_addr(ethhdr->h_source))
 198                 return false;
 199 
 200         /* create a copy of the skb, if needed, to modify it. */
 201         if (skb_cow(skb, 0) < 0)
 202                 return false;
 203 
 204         /* keep skb linear */
 205         if (skb_linearize(skb) < 0)
 206                 return false;
 207 
 208         return true;
 209 }
 210 
 211 /**
 212  * batadv_recv_my_icmp_packet() - receive an icmp packet locally
 213  * @bat_priv: the bat priv with all the soft interface information
 214  * @skb: icmp packet to process
 215  *
 216  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 217  * otherwise.
 218  */
 219 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 220                                       struct sk_buff *skb)
 221 {
 222         struct batadv_hard_iface *primary_if = NULL;
 223         struct batadv_orig_node *orig_node = NULL;
 224         struct batadv_icmp_header *icmph;
 225         int res, ret = NET_RX_DROP;
 226 
 227         icmph = (struct batadv_icmp_header *)skb->data;
 228 
 229         switch (icmph->msg_type) {
 230         case BATADV_ECHO_REPLY:
 231         case BATADV_DESTINATION_UNREACHABLE:
 232         case BATADV_TTL_EXCEEDED:
 233                 /* receive the packet */
 234                 if (skb_linearize(skb) < 0)
 235                         break;
 236 
 237                 batadv_socket_receive_packet(icmph, skb->len);
 238                 break;
 239         case BATADV_ECHO_REQUEST:
 240                 /* answer echo request (ping) */
 241                 primary_if = batadv_primary_if_get_selected(bat_priv);
 242                 if (!primary_if)
 243                         goto out;
 244 
 245                 /* get routing information */
 246                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 247                 if (!orig_node)
 248                         goto out;
 249 
 250                 /* create a copy of the skb, if needed, to modify it. */
 251                 if (skb_cow(skb, ETH_HLEN) < 0)
 252                         goto out;
 253 
 254                 icmph = (struct batadv_icmp_header *)skb->data;
 255 
 256                 ether_addr_copy(icmph->dst, icmph->orig);
 257                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 258                 icmph->msg_type = BATADV_ECHO_REPLY;
 259                 icmph->ttl = BATADV_TTL;
 260 
 261                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 262                 if (res == NET_XMIT_SUCCESS)
 263                         ret = NET_RX_SUCCESS;
 264 
 265                 /* skb was consumed */
 266                 skb = NULL;
 267                 break;
 268         case BATADV_TP:
 269                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
 270                         goto out;
 271 
 272                 batadv_tp_meter_recv(bat_priv, skb);
 273                 ret = NET_RX_SUCCESS;
 274                 /* skb was consumed */
 275                 skb = NULL;
 276                 goto out;
 277         default:
 278                 /* drop unknown type */
 279                 goto out;
 280         }
 281 out:
 282         if (primary_if)
 283                 batadv_hardif_put(primary_if);
 284         if (orig_node)
 285                 batadv_orig_node_put(orig_node);
 286 
 287         kfree_skb(skb);
 288 
 289         return ret;
 290 }
 291 
 292 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 293                                          struct sk_buff *skb)
 294 {
 295         struct batadv_hard_iface *primary_if = NULL;
 296         struct batadv_orig_node *orig_node = NULL;
 297         struct batadv_icmp_packet *icmp_packet;
 298         int res, ret = NET_RX_DROP;
 299 
 300         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 301 
 302         /* send TTL exceeded if packet is an echo request (traceroute) */
 303         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 304                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 305                          icmp_packet->orig, icmp_packet->dst);
 306                 goto out;
 307         }
 308 
 309         primary_if = batadv_primary_if_get_selected(bat_priv);
 310         if (!primary_if)
 311                 goto out;
 312 
 313         /* get routing information */
 314         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 315         if (!orig_node)
 316                 goto out;
 317 
 318         /* create a copy of the skb, if needed, to modify it. */
 319         if (skb_cow(skb, ETH_HLEN) < 0)
 320                 goto out;
 321 
 322         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 323 
 324         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 325         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 326         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 327         icmp_packet->ttl = BATADV_TTL;
 328 
 329         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 330         if (res == NET_RX_SUCCESS)
 331                 ret = NET_XMIT_SUCCESS;
 332 
 333         /* skb was consumed */
 334         skb = NULL;
 335 
 336 out:
 337         if (primary_if)
 338                 batadv_hardif_put(primary_if);
 339         if (orig_node)
 340                 batadv_orig_node_put(orig_node);
 341 
 342         kfree_skb(skb);
 343 
 344         return ret;
 345 }
 346 
 347 /**
 348  * batadv_recv_icmp_packet() - Process incoming icmp packet
 349  * @skb: incoming packet buffer
 350  * @recv_if: incoming hard interface
 351  *
 352  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
 353  */
 354 int batadv_recv_icmp_packet(struct sk_buff *skb,
 355                             struct batadv_hard_iface *recv_if)
 356 {
 357         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 358         struct batadv_icmp_header *icmph;
 359         struct batadv_icmp_packet_rr *icmp_packet_rr;
 360         struct ethhdr *ethhdr;
 361         struct batadv_orig_node *orig_node = NULL;
 362         int hdr_size = sizeof(struct batadv_icmp_header);
 363         int res, ret = NET_RX_DROP;
 364 
 365         /* drop packet if it has not necessary minimum size */
 366         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 367                 goto free_skb;
 368 
 369         ethhdr = eth_hdr(skb);
 370 
 371         /* packet with unicast indication but non-unicast recipient */
 372         if (!is_valid_ether_addr(ethhdr->h_dest))
 373                 goto free_skb;
 374 
 375         /* packet with broadcast/multicast sender address */
 376         if (is_multicast_ether_addr(ethhdr->h_source))
 377                 goto free_skb;
 378 
 379         /* not for me */
 380         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 381                 goto free_skb;
 382 
 383         icmph = (struct batadv_icmp_header *)skb->data;
 384 
 385         /* add record route information if not full */
 386         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 387              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 388             skb->len >= sizeof(struct batadv_icmp_packet_rr)) {
 389                 if (skb_linearize(skb) < 0)
 390                         goto free_skb;
 391 
 392                 /* create a copy of the skb, if needed, to modify it. */
 393                 if (skb_cow(skb, ETH_HLEN) < 0)
 394                         goto free_skb;
 395 
 396                 ethhdr = eth_hdr(skb);
 397                 icmph = (struct batadv_icmp_header *)skb->data;
 398                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 399                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 400                         goto free_skb;
 401 
 402                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 403                                 ethhdr->h_dest);
 404                 icmp_packet_rr->rr_cur++;
 405         }
 406 
 407         /* packet for me */
 408         if (batadv_is_my_mac(bat_priv, icmph->dst))
 409                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 410 
 411         /* TTL exceeded */
 412         if (icmph->ttl < 2)
 413                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 414 
 415         /* get routing information */
 416         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 417         if (!orig_node)
 418                 goto free_skb;
 419 
 420         /* create a copy of the skb, if needed, to modify it. */
 421         if (skb_cow(skb, ETH_HLEN) < 0)
 422                 goto put_orig_node;
 423 
 424         icmph = (struct batadv_icmp_header *)skb->data;
 425 
 426         /* decrement ttl */
 427         icmph->ttl--;
 428 
 429         /* route it */
 430         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 431         if (res == NET_XMIT_SUCCESS)
 432                 ret = NET_RX_SUCCESS;
 433 
 434         /* skb was consumed */
 435         skb = NULL;
 436 
 437 put_orig_node:
 438         if (orig_node)
 439                 batadv_orig_node_put(orig_node);
 440 free_skb:
 441         kfree_skb(skb);
 442 
 443         return ret;
 444 }
 445 
 446 /**
 447  * batadv_check_unicast_packet() - Check for malformed unicast packets
 448  * @bat_priv: the bat priv with all the soft interface information
 449  * @skb: packet to check
 450  * @hdr_size: size of header to pull
 451  *
 452  * Check for short header and bad addresses in given packet.
 453  *
 454  * Return: negative value when check fails and 0 otherwise. The negative value
 455  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 456  * destination or source, and -EREMOTE for non-local (other host) destination.
 457  */
 458 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 459                                        struct sk_buff *skb, int hdr_size)
 460 {
 461         struct ethhdr *ethhdr;
 462 
 463         /* drop packet if it has not necessary minimum size */
 464         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 465                 return -ENODATA;
 466 
 467         ethhdr = eth_hdr(skb);
 468 
 469         /* packet with unicast indication but non-unicast recipient */
 470         if (!is_valid_ether_addr(ethhdr->h_dest))
 471                 return -EBADR;
 472 
 473         /* packet with broadcast/multicast sender address */
 474         if (is_multicast_ether_addr(ethhdr->h_source))
 475                 return -EBADR;
 476 
 477         /* not for me */
 478         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 479                 return -EREMOTE;
 480 
 481         return 0;
 482 }
 483 
 484 /**
 485  * batadv_last_bonding_get() - Get last_bonding_candidate of orig_node
 486  * @orig_node: originator node whose last bonding candidate should be retrieved
 487  *
 488  * Return: last bonding candidate of router or NULL if not found
 489  *
 490  * The object is returned with refcounter increased by 1.
 491  */
 492 static struct batadv_orig_ifinfo *
 493 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
 494 {
 495         struct batadv_orig_ifinfo *last_bonding_candidate;
 496 
 497         spin_lock_bh(&orig_node->neigh_list_lock);
 498         last_bonding_candidate = orig_node->last_bonding_candidate;
 499 
 500         if (last_bonding_candidate)
 501                 kref_get(&last_bonding_candidate->refcount);
 502         spin_unlock_bh(&orig_node->neigh_list_lock);
 503 
 504         return last_bonding_candidate;
 505 }
 506 
 507 /**
 508  * batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node
 509  * @orig_node: originator node whose bonding candidates should be replaced
 510  * @new_candidate: new bonding candidate or NULL
 511  */
 512 static void
 513 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 514                             struct batadv_orig_ifinfo *new_candidate)
 515 {
 516         struct batadv_orig_ifinfo *old_candidate;
 517 
 518         spin_lock_bh(&orig_node->neigh_list_lock);
 519         old_candidate = orig_node->last_bonding_candidate;
 520 
 521         if (new_candidate)
 522                 kref_get(&new_candidate->refcount);
 523         orig_node->last_bonding_candidate = new_candidate;
 524         spin_unlock_bh(&orig_node->neigh_list_lock);
 525 
 526         if (old_candidate)
 527                 batadv_orig_ifinfo_put(old_candidate);
 528 }
 529 
 530 /**
 531  * batadv_find_router() - find a suitable router for this originator
 532  * @bat_priv: the bat priv with all the soft interface information
 533  * @orig_node: the destination node
 534  * @recv_if: pointer to interface this packet was received on
 535  *
 536  * Return: the router which should be used for this orig_node on
 537  * this interface, or NULL if not available.
 538  */
 539 struct batadv_neigh_node *
 540 batadv_find_router(struct batadv_priv *bat_priv,
 541                    struct batadv_orig_node *orig_node,
 542                    struct batadv_hard_iface *recv_if)
 543 {
 544         struct batadv_algo_ops *bao = bat_priv->algo_ops;
 545         struct batadv_neigh_node *first_candidate_router = NULL;
 546         struct batadv_neigh_node *next_candidate_router = NULL;
 547         struct batadv_neigh_node *router, *cand_router = NULL;
 548         struct batadv_neigh_node *last_cand_router = NULL;
 549         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 550         struct batadv_orig_ifinfo *next_candidate = NULL;
 551         struct batadv_orig_ifinfo *last_candidate;
 552         bool last_candidate_found = false;
 553 
 554         if (!orig_node)
 555                 return NULL;
 556 
 557         router = batadv_orig_router_get(orig_node, recv_if);
 558 
 559         if (!router)
 560                 return router;
 561 
 562         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 563          * and if activated.
 564          */
 565         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 566                 return router;
 567 
 568         /* bonding: loop through the list of possible routers found
 569          * for the various outgoing interfaces and find a candidate after
 570          * the last chosen bonding candidate (next_candidate). If no such
 571          * router is found, use the first candidate found (the previously
 572          * chosen bonding candidate might have been the last one in the list).
 573          * If this can't be found either, return the previously chosen
 574          * router - obviously there are no other candidates.
 575          */
 576         rcu_read_lock();
 577         last_candidate = batadv_last_bonding_get(orig_node);
 578         if (last_candidate)
 579                 last_cand_router = rcu_dereference(last_candidate->router);
 580 
 581         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 582                 /* acquire some structures and references ... */
 583                 if (!kref_get_unless_zero(&cand->refcount))
 584                         continue;
 585 
 586                 cand_router = rcu_dereference(cand->router);
 587                 if (!cand_router)
 588                         goto next;
 589 
 590                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 591                         cand_router = NULL;
 592                         goto next;
 593                 }
 594 
 595                 /* alternative candidate should be good enough to be
 596                  * considered
 597                  */
 598                 if (!bao->neigh.is_similar_or_better(cand_router,
 599                                                      cand->if_outgoing, router,
 600                                                      recv_if))
 601                         goto next;
 602 
 603                 /* don't use the same router twice */
 604                 if (last_cand_router == cand_router)
 605                         goto next;
 606 
 607                 /* mark the first possible candidate */
 608                 if (!first_candidate) {
 609                         kref_get(&cand_router->refcount);
 610                         kref_get(&cand->refcount);
 611                         first_candidate = cand;
 612                         first_candidate_router = cand_router;
 613                 }
 614 
 615                 /* check if the loop has already passed the previously selected
 616                  * candidate ... this function should select the next candidate
 617                  * AFTER the previously used bonding candidate.
 618                  */
 619                 if (!last_candidate || last_candidate_found) {
 620                         next_candidate = cand;
 621                         next_candidate_router = cand_router;
 622                         break;
 623                 }
 624 
 625                 if (last_candidate == cand)
 626                         last_candidate_found = true;
 627 next:
 628                 /* free references */
 629                 if (cand_router) {
 630                         batadv_neigh_node_put(cand_router);
 631                         cand_router = NULL;
 632                 }
 633                 batadv_orig_ifinfo_put(cand);
 634         }
 635         rcu_read_unlock();
 636 
 637         /* After finding candidates, handle the three cases:
 638          * 1) there is a next candidate, use that
 639          * 2) there is no next candidate, use the first of the list
 640          * 3) there is no candidate at all, return the default router
 641          */
 642         if (next_candidate) {
 643                 batadv_neigh_node_put(router);
 644 
 645                 kref_get(&next_candidate_router->refcount);
 646                 router = next_candidate_router;
 647                 batadv_last_bonding_replace(orig_node, next_candidate);
 648         } else if (first_candidate) {
 649                 batadv_neigh_node_put(router);
 650 
 651                 kref_get(&first_candidate_router->refcount);
 652                 router = first_candidate_router;
 653                 batadv_last_bonding_replace(orig_node, first_candidate);
 654         } else {
 655                 batadv_last_bonding_replace(orig_node, NULL);
 656         }
 657 
 658         /* cleanup of candidates */
 659         if (first_candidate) {
 660                 batadv_neigh_node_put(first_candidate_router);
 661                 batadv_orig_ifinfo_put(first_candidate);
 662         }
 663 
 664         if (next_candidate) {
 665                 batadv_neigh_node_put(next_candidate_router);
 666                 batadv_orig_ifinfo_put(next_candidate);
 667         }
 668 
 669         if (last_candidate)
 670                 batadv_orig_ifinfo_put(last_candidate);
 671 
 672         return router;
 673 }
 674 
 675 static int batadv_route_unicast_packet(struct sk_buff *skb,
 676                                        struct batadv_hard_iface *recv_if)
 677 {
 678         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 679         struct batadv_orig_node *orig_node = NULL;
 680         struct batadv_unicast_packet *unicast_packet;
 681         struct ethhdr *ethhdr = eth_hdr(skb);
 682         int res, hdr_len, ret = NET_RX_DROP;
 683         unsigned int len;
 684 
 685         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 686 
 687         /* TTL exceeded */
 688         if (unicast_packet->ttl < 2) {
 689                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 690                          ethhdr->h_source, unicast_packet->dest);
 691                 goto free_skb;
 692         }
 693 
 694         /* get routing information */
 695         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 696 
 697         if (!orig_node)
 698                 goto free_skb;
 699 
 700         /* create a copy of the skb, if needed, to modify it. */
 701         if (skb_cow(skb, ETH_HLEN) < 0)
 702                 goto put_orig_node;
 703 
 704         /* decrement ttl */
 705         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 706         unicast_packet->ttl--;
 707 
 708         switch (unicast_packet->packet_type) {
 709         case BATADV_UNICAST_4ADDR:
 710                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 711                 break;
 712         case BATADV_UNICAST:
 713                 hdr_len = sizeof(struct batadv_unicast_packet);
 714                 break;
 715         default:
 716                 /* other packet types not supported - yet */
 717                 hdr_len = -1;
 718                 break;
 719         }
 720 
 721         if (hdr_len > 0)
 722                 batadv_skb_set_priority(skb, hdr_len);
 723 
 724         len = skb->len;
 725         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 726 
 727         /* translate transmit result into receive result */
 728         if (res == NET_XMIT_SUCCESS) {
 729                 ret = NET_RX_SUCCESS;
 730                 /* skb was transmitted and consumed */
 731                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 732                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 733                                    len + ETH_HLEN);
 734         }
 735 
 736         /* skb was consumed */
 737         skb = NULL;
 738 
 739 put_orig_node:
 740         batadv_orig_node_put(orig_node);
 741 free_skb:
 742         kfree_skb(skb);
 743 
 744         return ret;
 745 }
 746 
 747 /**
 748  * batadv_reroute_unicast_packet() - update the unicast header for re-routing
 749  * @bat_priv: the bat priv with all the soft interface information
 750  * @skb: unicast packet to process
 751  * @unicast_packet: the unicast header to be updated
 752  * @dst_addr: the payload destination
 753  * @vid: VLAN identifier
 754  *
 755  * Search the translation table for dst_addr and update the unicast header with
 756  * the new corresponding information (originator address where the destination
 757  * client currently is and its known TTVN)
 758  *
 759  * Return: true if the packet header has been updated, false otherwise
 760  */
 761 static bool
 762 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
 763                               struct batadv_unicast_packet *unicast_packet,
 764                               u8 *dst_addr, unsigned short vid)
 765 {
 766         struct batadv_orig_node *orig_node = NULL;
 767         struct batadv_hard_iface *primary_if = NULL;
 768         bool ret = false;
 769         u8 *orig_addr, orig_ttvn;
 770 
 771         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 772                 primary_if = batadv_primary_if_get_selected(bat_priv);
 773                 if (!primary_if)
 774                         goto out;
 775                 orig_addr = primary_if->net_dev->dev_addr;
 776                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 777         } else {
 778                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 779                                                      vid);
 780                 if (!orig_node)
 781                         goto out;
 782 
 783                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 784                         goto out;
 785 
 786                 orig_addr = orig_node->orig;
 787                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 788         }
 789 
 790         /* update the packet header */
 791         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 792         ether_addr_copy(unicast_packet->dest, orig_addr);
 793         unicast_packet->ttvn = orig_ttvn;
 794         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 795 
 796         ret = true;
 797 out:
 798         if (primary_if)
 799                 batadv_hardif_put(primary_if);
 800         if (orig_node)
 801                 batadv_orig_node_put(orig_node);
 802 
 803         return ret;
 804 }
 805 
 806 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 807                                       struct sk_buff *skb, int hdr_len)
 808 {
 809         struct batadv_unicast_packet *unicast_packet;
 810         struct batadv_hard_iface *primary_if;
 811         struct batadv_orig_node *orig_node;
 812         u8 curr_ttvn, old_ttvn;
 813         struct ethhdr *ethhdr;
 814         unsigned short vid;
 815         int is_old_ttvn;
 816 
 817         /* check if there is enough data before accessing it */
 818         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 819                 return false;
 820 
 821         /* create a copy of the skb (in case of for re-routing) to modify it. */
 822         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 823                 return false;
 824 
 825         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 826         vid = batadv_get_vid(skb, hdr_len);
 827         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 828 
 829         /* check if the destination client was served by this node and it is now
 830          * roaming. In this case, it means that the node has got a ROAM_ADV
 831          * message and that it knows the new destination in the mesh to re-route
 832          * the packet to
 833          */
 834         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 835                 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
 836                                                   ethhdr->h_dest, vid))
 837                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 838                                                bat_priv,
 839                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 840                                                unicast_packet->dest,
 841                                                ethhdr->h_dest);
 842                 /* at this point the mesh destination should have been
 843                  * substituted with the originator address found in the global
 844                  * table. If not, let the packet go untouched anyway because
 845                  * there is nothing the node can do
 846                  */
 847                 return true;
 848         }
 849 
 850         /* retrieve the TTVN known by this node for the packet destination. This
 851          * value is used later to check if the node which sent (or re-routed
 852          * last time) the packet had an updated information or not
 853          */
 854         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 855         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 856                 orig_node = batadv_orig_hash_find(bat_priv,
 857                                                   unicast_packet->dest);
 858                 /* if it is not possible to find the orig_node representing the
 859                  * destination, the packet can immediately be dropped as it will
 860                  * not be possible to deliver it
 861                  */
 862                 if (!orig_node)
 863                         return false;
 864 
 865                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 866                 batadv_orig_node_put(orig_node);
 867         }
 868 
 869         /* check if the TTVN contained in the packet is fresher than what the
 870          * node knows
 871          */
 872         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 873         if (!is_old_ttvn)
 874                 return true;
 875 
 876         old_ttvn = unicast_packet->ttvn;
 877         /* the packet was forged based on outdated network information. Its
 878          * destination can possibly be updated and forwarded towards the new
 879          * target host
 880          */
 881         if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
 882                                           ethhdr->h_dest, vid)) {
 883                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 884                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 885                                        unicast_packet->dest, ethhdr->h_dest,
 886                                        old_ttvn, curr_ttvn);
 887                 return true;
 888         }
 889 
 890         /* the packet has not been re-routed: either the destination is
 891          * currently served by this node or there is no destination at all and
 892          * it is possible to drop the packet
 893          */
 894         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 895                 return false;
 896 
 897         /* update the header in order to let the packet be delivered to this
 898          * node's soft interface
 899          */
 900         primary_if = batadv_primary_if_get_selected(bat_priv);
 901         if (!primary_if)
 902                 return false;
 903 
 904         /* update the packet header */
 905         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 906         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 907         unicast_packet->ttvn = curr_ttvn;
 908         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 909 
 910         batadv_hardif_put(primary_if);
 911 
 912         return true;
 913 }
 914 
 915 /**
 916  * batadv_recv_unhandled_unicast_packet() - receive and process packets which
 917  *      are in the unicast number space but not yet known to the implementation
 918  * @skb: unicast tvlv packet to process
 919  * @recv_if: pointer to interface this packet was received on
 920  *
 921  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 922  * otherwise.
 923  */
 924 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 925                                          struct batadv_hard_iface *recv_if)
 926 {
 927         struct batadv_unicast_packet *unicast_packet;
 928         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 929         int check, hdr_size = sizeof(*unicast_packet);
 930 
 931         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 932         if (check < 0)
 933                 goto free_skb;
 934 
 935         /* we don't know about this type, drop it. */
 936         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 937         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 938                 goto free_skb;
 939 
 940         return batadv_route_unicast_packet(skb, recv_if);
 941 
 942 free_skb:
 943         kfree_skb(skb);
 944         return NET_RX_DROP;
 945 }
 946 
 947 /**
 948  * batadv_recv_unicast_packet() - Process incoming unicast packet
 949  * @skb: incoming packet buffer
 950  * @recv_if: incoming hard interface
 951  *
 952  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
 953  */
 954 int batadv_recv_unicast_packet(struct sk_buff *skb,
 955                                struct batadv_hard_iface *recv_if)
 956 {
 957         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 958         struct batadv_unicast_packet *unicast_packet;
 959         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 960         u8 *orig_addr, *orig_addr_gw;
 961         struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
 962         int check, hdr_size = sizeof(*unicast_packet);
 963         enum batadv_subtype subtype;
 964         int ret = NET_RX_DROP;
 965         bool is4addr, is_gw;
 966 
 967         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 968         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 969         /* the caller function should have already pulled 2 bytes */
 970         if (is4addr)
 971                 hdr_size = sizeof(*unicast_4addr_packet);
 972 
 973         /* function returns -EREMOTE for promiscuous packets */
 974         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 975 
 976         /* Even though the packet is not for us, we might save it to use for
 977          * decoding a later received coded packet
 978          */
 979         if (check == -EREMOTE)
 980                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 981 
 982         if (check < 0)
 983                 goto free_skb;
 984         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 985                 goto free_skb;
 986 
 987         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 988 
 989         /* packet for me */
 990         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 991                 /* If this is a unicast packet from another backgone gw,
 992                  * drop it.
 993                  */
 994                 orig_addr_gw = eth_hdr(skb)->h_source;
 995                 orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw);
 996                 if (orig_node_gw) {
 997                         is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw,
 998                                                           hdr_size);
 999                         batadv_orig_node_put(orig_node_gw);
1000                         if (is_gw) {
1001                                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
1002                                            "%s(): Dropped unicast pkt received from another backbone gw %pM.\n",
1003                                            __func__, orig_addr_gw);
1004                                 goto free_skb;
1005                         }
1006                 }
1007 
1008                 if (is4addr) {
1009                         unicast_4addr_packet =
1010                                 (struct batadv_unicast_4addr_packet *)skb->data;
1011                         subtype = unicast_4addr_packet->subtype;
1012                         batadv_dat_inc_counter(bat_priv, subtype);
1013 
1014                         /* Only payload data should be considered for speedy
1015                          * join. For example, DAT also uses unicast 4addr
1016                          * types, but those packets should not be considered
1017                          * for speedy join, since the clients do not actually
1018                          * reside at the sending originator.
1019                          */
1020                         if (subtype == BATADV_P_DATA) {
1021                                 orig_addr = unicast_4addr_packet->src;
1022                                 orig_node = batadv_orig_hash_find(bat_priv,
1023                                                                   orig_addr);
1024                         }
1025                 }
1026 
1027                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1028                                                           hdr_size))
1029                         goto rx_success;
1030                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1031                                                         hdr_size))
1032                         goto rx_success;
1033 
1034                 batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1035 
1036                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
1037                                     orig_node);
1038 
1039 rx_success:
1040                 if (orig_node)
1041                         batadv_orig_node_put(orig_node);
1042 
1043                 return NET_RX_SUCCESS;
1044         }
1045 
1046         ret = batadv_route_unicast_packet(skb, recv_if);
1047         /* skb was consumed */
1048         skb = NULL;
1049 
1050 free_skb:
1051         kfree_skb(skb);
1052 
1053         return ret;
1054 }
1055 
1056 /**
1057  * batadv_recv_unicast_tvlv() - receive and process unicast tvlv packets
1058  * @skb: unicast tvlv packet to process
1059  * @recv_if: pointer to interface this packet was received on
1060  *
1061  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1062  * otherwise.
1063  */
1064 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1065                              struct batadv_hard_iface *recv_if)
1066 {
1067         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1068         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1069         unsigned char *tvlv_buff;
1070         u16 tvlv_buff_len;
1071         int hdr_size = sizeof(*unicast_tvlv_packet);
1072         int ret = NET_RX_DROP;
1073 
1074         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1075                 goto free_skb;
1076 
1077         /* the header is likely to be modified while forwarding */
1078         if (skb_cow(skb, hdr_size) < 0)
1079                 goto free_skb;
1080 
1081         /* packet needs to be linearized to access the tvlv content */
1082         if (skb_linearize(skb) < 0)
1083                 goto free_skb;
1084 
1085         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1086 
1087         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1088         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1089 
1090         if (tvlv_buff_len > skb->len - hdr_size)
1091                 goto free_skb;
1092 
1093         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1094                                              unicast_tvlv_packet->src,
1095                                              unicast_tvlv_packet->dst,
1096                                              tvlv_buff, tvlv_buff_len);
1097 
1098         if (ret != NET_RX_SUCCESS) {
1099                 ret = batadv_route_unicast_packet(skb, recv_if);
1100                 /* skb was consumed */
1101                 skb = NULL;
1102         }
1103 
1104 free_skb:
1105         kfree_skb(skb);
1106 
1107         return ret;
1108 }
1109 
1110 /**
1111  * batadv_recv_frag_packet() - process received fragment
1112  * @skb: the received fragment
1113  * @recv_if: interface that the skb is received on
1114  *
1115  * This function does one of the three following things: 1) Forward fragment, if
1116  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1117  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1118  *
1119  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1120  */
1121 int batadv_recv_frag_packet(struct sk_buff *skb,
1122                             struct batadv_hard_iface *recv_if)
1123 {
1124         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1125         struct batadv_orig_node *orig_node_src = NULL;
1126         struct batadv_frag_packet *frag_packet;
1127         int ret = NET_RX_DROP;
1128 
1129         if (batadv_check_unicast_packet(bat_priv, skb,
1130                                         sizeof(*frag_packet)) < 0)
1131                 goto free_skb;
1132 
1133         frag_packet = (struct batadv_frag_packet *)skb->data;
1134         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1135         if (!orig_node_src)
1136                 goto free_skb;
1137 
1138         skb->priority = frag_packet->priority + 256;
1139 
1140         /* Route the fragment if it is not for us and too big to be merged. */
1141         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1142             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1143                 /* skb was consumed */
1144                 skb = NULL;
1145                 ret = NET_RX_SUCCESS;
1146                 goto put_orig_node;
1147         }
1148 
1149         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1150         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1151 
1152         /* Add fragment to buffer and merge if possible. */
1153         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1154                 goto put_orig_node;
1155 
1156         /* Deliver merged packet to the appropriate handler, if it was
1157          * merged
1158          */
1159         if (skb) {
1160                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1161                                        &recv_if->batman_adv_ptype, NULL);
1162                 /* skb was consumed */
1163                 skb = NULL;
1164         }
1165 
1166         ret = NET_RX_SUCCESS;
1167 
1168 put_orig_node:
1169         batadv_orig_node_put(orig_node_src);
1170 free_skb:
1171         kfree_skb(skb);
1172 
1173         return ret;
1174 }
1175 
1176 /**
1177  * batadv_recv_bcast_packet() - Process incoming broadcast packet
1178  * @skb: incoming packet buffer
1179  * @recv_if: incoming hard interface
1180  *
1181  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
1182  */
1183 int batadv_recv_bcast_packet(struct sk_buff *skb,
1184                              struct batadv_hard_iface *recv_if)
1185 {
1186         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1187         struct batadv_orig_node *orig_node = NULL;
1188         struct batadv_bcast_packet *bcast_packet;
1189         struct ethhdr *ethhdr;
1190         int hdr_size = sizeof(*bcast_packet);
1191         int ret = NET_RX_DROP;
1192         s32 seq_diff;
1193         u32 seqno;
1194 
1195         /* drop packet if it has not necessary minimum size */
1196         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1197                 goto free_skb;
1198 
1199         ethhdr = eth_hdr(skb);
1200 
1201         /* packet with broadcast indication but unicast recipient */
1202         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1203                 goto free_skb;
1204 
1205         /* packet with broadcast/multicast sender address */
1206         if (is_multicast_ether_addr(ethhdr->h_source))
1207                 goto free_skb;
1208 
1209         /* ignore broadcasts sent by myself */
1210         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1211                 goto free_skb;
1212 
1213         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1214 
1215         /* ignore broadcasts originated by myself */
1216         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1217                 goto free_skb;
1218 
1219         if (bcast_packet->ttl < 2)
1220                 goto free_skb;
1221 
1222         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1223 
1224         if (!orig_node)
1225                 goto free_skb;
1226 
1227         spin_lock_bh(&orig_node->bcast_seqno_lock);
1228 
1229         seqno = ntohl(bcast_packet->seqno);
1230         /* check whether the packet is a duplicate */
1231         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1232                             seqno))
1233                 goto spin_unlock;
1234 
1235         seq_diff = seqno - orig_node->last_bcast_seqno;
1236 
1237         /* check whether the packet is old and the host just restarted. */
1238         if (batadv_window_protected(bat_priv, seq_diff,
1239                                     BATADV_BCAST_MAX_AGE,
1240                                     &orig_node->bcast_seqno_reset, NULL))
1241                 goto spin_unlock;
1242 
1243         /* mark broadcast in flood history, update window position
1244          * if required.
1245          */
1246         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1247                 orig_node->last_bcast_seqno = seqno;
1248 
1249         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1250 
1251         /* check whether this has been sent by another originator before */
1252         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1253                 goto free_skb;
1254 
1255         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1256 
1257         /* rebroadcast packet */
1258         batadv_add_bcast_packet_to_list(bat_priv, skb, 1, false);
1259 
1260         /* don't hand the broadcast up if it is from an originator
1261          * from the same backbone.
1262          */
1263         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1264                 goto free_skb;
1265 
1266         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1267                 goto rx_success;
1268         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1269                 goto rx_success;
1270 
1271         batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1272 
1273         /* broadcast for me */
1274         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1275 
1276 rx_success:
1277         ret = NET_RX_SUCCESS;
1278         goto out;
1279 
1280 spin_unlock:
1281         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1282 free_skb:
1283         kfree_skb(skb);
1284 out:
1285         if (orig_node)
1286                 batadv_orig_node_put(orig_node);
1287         return ret;
1288 }