net/batman-adv/bridge_loop_avoidance.c

   1 /* Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
   2  *
   3  * 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, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "hash.h"
  22 #include "hard-interface.h"
  23 #include "originator.h"
  24 #include "bridge_loop_avoidance.h"
  25 #include "translation-table.h"
  26 #include "send.h"
  27
  28 #include <linux/etherdevice.h>
  29 #include <linux/crc16.h>
  30 #include <linux/if_arp.h>
  31 #include <net/arp.h>
  32 #include <linux/if_vlan.h>
  33
  34 static const uint8_t announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
  35
  36 static void bla_periodic_work(struct work_struct *work);
  37 static void bla_send_announce(struct bat_priv *bat_priv,
  38                               struct backbone_gw *backbone_gw);
  39
  40 /* return the index of the claim */
  41 static inline uint32_t choose_claim(const void *data, uint32_t size)
  42 {
  43         const unsigned char *key = data;
  44         uint32_t hash = 0;
  45         size_t i;
  46
  47         for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
  48                 hash += key[i];
  49                 hash += (hash << 10);
  50                 hash ^= (hash >> 6);
  51         }
  52
  53         hash += (hash << 3);
  54         hash ^= (hash >> 11);
  55         hash += (hash << 15);
  56
  57         return hash % size;
  58 }
  59
  60 /* return the index of the backbone gateway */
  61 static inline uint32_t choose_backbone_gw(const void *data, uint32_t size)
  62 {
  63         const unsigned char *key = data;
  64         uint32_t hash = 0;
  65         size_t i;
  66
  67         for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
  68                 hash += key[i];
  69                 hash += (hash << 10);
  70                 hash ^= (hash >> 6);
  71         }
  72
  73         hash += (hash << 3);
  74         hash ^= (hash >> 11);
  75         hash += (hash << 15);
  76
  77         return hash % size;
  78 }
  79
  80
  81 /* compares address and vid of two backbone gws */
  82 static int compare_backbone_gw(const struct hlist_node *node, const void *data2)
  83 {
  84         const void *data1 = container_of(node, struct backbone_gw,
  85                                          hash_entry);
  86
  87         return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
  88 }
  89
  90 /* compares address and vid of two claims */
  91 static int compare_claim(const struct hlist_node *node, const void *data2)
  92 {
  93         const void *data1 = container_of(node, struct claim,
  94                                          hash_entry);
  95
  96         return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
  97 }
  98
  99 /* free a backbone gw */
 100 static void backbone_gw_free_ref(struct backbone_gw *backbone_gw)
 101 {
 102         if (atomic_dec_and_test(&backbone_gw->refcount))
 103                 kfree_rcu(backbone_gw, rcu);
 104 }
 105
 106 /* finally deinitialize the claim */
 107 static void claim_free_rcu(struct rcu_head *rcu)
 108 {
 109         struct claim *claim;
 110
 111         claim = container_of(rcu, struct claim, rcu);
 112
 113         backbone_gw_free_ref(claim->backbone_gw);
 114         kfree(claim);
 115 }
 116
 117 /* free a claim, call claim_free_rcu if its the last reference */
 118 static void claim_free_ref(struct claim *claim)
 119 {
 120         if (atomic_dec_and_test(&claim->refcount))
 121                 call_rcu(&claim->rcu, claim_free_rcu);
 122 }
 123
 124 /* @bat_priv: the bat priv with all the soft interface information
 125  * @data: search data (may be local/static data)
 126  *
 127  * looks for a claim in the hash, and returns it if found
 128  * or NULL otherwise.
 129  */
 130 static struct claim *claim_hash_find(struct bat_priv *bat_priv,
 131                                      struct claim *data)
 132 {
 133         struct hashtable_t *hash = bat_priv->claim_hash;
 134         struct hlist_head *head;
 135         struct hlist_node *node;
 136         struct claim *claim;
 137         struct claim *claim_tmp = NULL;
 138         int index;
 139
 140         if (!hash)
 141                 return NULL;
 142
 143         index = choose_claim(data, hash->size);
 144         head = &hash->table[index];
 145
 146         rcu_read_lock();
 147         hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 148                 if (!compare_claim(&claim->hash_entry, data))
 149                         continue;
 150
 151                 if (!atomic_inc_not_zero(&claim->refcount))
 152                         continue;
 153
 154                 claim_tmp = claim;
 155                 break;
 156         }
 157         rcu_read_unlock();
 158
 159         return claim_tmp;
 160 }
 161
 162 /* @bat_priv: the bat priv with all the soft interface information
 163  * @addr: the address of the originator
 164  * @vid: the VLAN ID
 165  *
 166  * looks for a claim in the hash, and returns it if found
 167  * or NULL otherwise.
 168  */
 169 static struct backbone_gw *backbone_hash_find(struct bat_priv *bat_priv,
 170                                               uint8_t *addr, short vid)
 171 {
 172         struct hashtable_t *hash = bat_priv->backbone_hash;
 173         struct hlist_head *head;
 174         struct hlist_node *node;
 175         struct backbone_gw search_entry, *backbone_gw;
 176         struct backbone_gw *backbone_gw_tmp = NULL;
 177         int index;
 178
 179         if (!hash)
 180                 return NULL;
 181
 182         memcpy(search_entry.orig, addr, ETH_ALEN);
 183         search_entry.vid = vid;
 184
 185         index = choose_backbone_gw(&search_entry, hash->size);
 186         head = &hash->table[index];
 187
 188         rcu_read_lock();
 189         hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
 190                 if (!compare_backbone_gw(&backbone_gw->hash_entry,
 191                                          &search_entry))
 192                         continue;
 193
 194                 if (!atomic_inc_not_zero(&backbone_gw->refcount))
 195                         continue;
 196
 197                 backbone_gw_tmp = backbone_gw;
 198                 break;
 199         }
 200         rcu_read_unlock();
 201
 202         return backbone_gw_tmp;
 203 }
 204
 205 /* delete all claims for a backbone */
 206 static void bla_del_backbone_claims(struct backbone_gw *backbone_gw)
 207 {
 208         struct hashtable_t *hash;
 209         struct hlist_node *node, *node_tmp;
 210         struct hlist_head *head;
 211         struct claim *claim;
 212         int i;
 213         spinlock_t *list_lock;  /* protects write access to the hash lists */
 214
 215         hash = backbone_gw->bat_priv->claim_hash;
 216         if (!hash)
 217                 return;
 218
 219         for (i = 0; i < hash->size; i++) {
 220                 head = &hash->table[i];
 221                 list_lock = &hash->list_locks[i];
 222
 223                 spin_lock_bh(list_lock);
 224                 hlist_for_each_entry_safe(claim, node, node_tmp,
 225                                           head, hash_entry) {
 226
 227                         if (claim->backbone_gw != backbone_gw)
 228                                 continue;
 229
 230                         claim_free_ref(claim);
 231                         hlist_del_rcu(node);
 232                 }
 233                 spin_unlock_bh(list_lock);
 234         }
 235
 236         /* all claims gone, intialize CRC */
 237         backbone_gw->crc = BLA_CRC_INIT;
 238 }
 239
 240 /* @bat_priv: the bat priv with all the soft interface information
 241  * @orig: the mac address to be announced within the claim
 242  * @vid: the VLAN ID
 243  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 244  *
 245  * sends a claim frame according to the provided info.
 246  */
 247 static void bla_send_claim(struct bat_priv *bat_priv, uint8_t *mac,
 248                            short vid, int claimtype)
 249 {
 250         struct sk_buff *skb;
 251         struct ethhdr *ethhdr;
 252         struct hard_iface *primary_if;
 253         struct net_device *soft_iface;
 254         uint8_t *hw_src;
 255         struct bla_claim_dst local_claim_dest;
 256         __be32 zeroip = 0;
 257
 258         primary_if = batadv_primary_if_get_selected(bat_priv);
 259         if (!primary_if)
 260                 return;
 261
 262         memcpy(&local_claim_dest, &bat_priv->claim_dest,
 263                sizeof(local_claim_dest));
 264         local_claim_dest.type = claimtype;
 265
 266         soft_iface = primary_if->soft_iface;
 267
 268         skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
 269                          /* IP DST: 0.0.0.0 */
 270                          zeroip,
 271                          primary_if->soft_iface,
 272                          /* IP SRC: 0.0.0.0 */
 273                          zeroip,
 274                          /* Ethernet DST: Broadcast */
 275                          NULL,
 276                          /* Ethernet SRC/HW SRC:  originator mac */
 277                          primary_if->net_dev->dev_addr,
 278                          /* HW DST: FF:43:05:XX:00:00
 279                           * with XX   = claim type
 280                           * and YY:YY = group id
 281                           */
 282                          (uint8_t *)&local_claim_dest);
 283
 284         if (!skb)
 285                 goto out;
 286
 287         ethhdr = (struct ethhdr *)skb->data;
 288         hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
 289
 290         /* now we pretend that the client would have sent this ... */
 291         switch (claimtype) {
 292         case CLAIM_TYPE_ADD:
 293                 /* normal claim frame
 294                  * set Ethernet SRC to the clients mac
 295                  */
 296                 memcpy(ethhdr->h_source, mac, ETH_ALEN);
 297                 bat_dbg(DBG_BLA, bat_priv,
 298                         "bla_send_claim(): CLAIM %pM on vid %d\n", mac, vid);
 299                 break;
 300         case CLAIM_TYPE_DEL:
 301                 /* unclaim frame
 302                  * set HW SRC to the clients mac
 303                  */
 304                 memcpy(hw_src, mac, ETH_ALEN);
 305                 bat_dbg(DBG_BLA, bat_priv,
 306                         "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac, vid);
 307                 break;
 308         case CLAIM_TYPE_ANNOUNCE:
 309                 /* announcement frame
 310                  * set HW SRC to the special mac containg the crc
 311                  */
 312                 memcpy(hw_src, mac, ETH_ALEN);
 313                 bat_dbg(DBG_BLA, bat_priv,
 314                         "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
 315                         ethhdr->h_source, vid);
 316                 break;
 317         case CLAIM_TYPE_REQUEST:
 318                 /* request frame
 319                  * set HW SRC to the special mac containg the crc
 320                  */
 321                 memcpy(hw_src, mac, ETH_ALEN);
 322                 memcpy(ethhdr->h_dest, mac, ETH_ALEN);
 323                 bat_dbg(DBG_BLA, bat_priv,
 324                         "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
 325                         ethhdr->h_source, ethhdr->h_dest, vid);
 326                 break;
 327
 328         }
 329
 330         if (vid != -1)
 331                 skb = vlan_insert_tag(skb, vid);
 332
 333         skb_reset_mac_header(skb);
 334         skb->protocol = eth_type_trans(skb, soft_iface);
 335         bat_priv->stats.rx_packets++;
 336         bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;
 337         soft_iface->last_rx = jiffies;
 338
 339         netif_rx(skb);
 340 out:
 341         if (primary_if)
 342                 batadv_hardif_free_ref(primary_if);
 343 }
 344
 345 /* @bat_priv: the bat priv with all the soft interface information
 346  * @orig: the mac address of the originator
 347  * @vid: the VLAN ID
 348  *
 349  * searches for the backbone gw or creates a new one if it could not
 350  * be found.
 351  */
 352 static struct backbone_gw *bla_get_backbone_gw(struct bat_priv *bat_priv,
 353                                                uint8_t *orig, short vid)
 354 {
 355         struct backbone_gw *entry;
 356         struct orig_node *orig_node;
 357         int hash_added;
 358
 359         entry = backbone_hash_find(bat_priv, orig, vid);
 360
 361         if (entry)
 362                 return entry;
 363
 364         bat_dbg(DBG_BLA, bat_priv,
 365                 "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 366                 orig, vid);
 367
 368         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 369         if (!entry)
 370                 return NULL;
 371
 372         entry->vid = vid;
 373         entry->lasttime = jiffies;
 374         entry->crc = BLA_CRC_INIT;
 375         entry->bat_priv = bat_priv;
 376         atomic_set(&entry->request_sent, 0);
 377         memcpy(entry->orig, orig, ETH_ALEN);
 378
 379         /* one for the hash, one for returning */
 380         atomic_set(&entry->refcount, 2);
 381
 382         hash_added = batadv_hash_add(bat_priv->backbone_hash,
 383                                      compare_backbone_gw, choose_backbone_gw,
 384                                      entry, &entry->hash_entry);
 385
 386         if (unlikely(hash_added != 0)) {
 387                 /* hash failed, free the structure */
 388                 kfree(entry);
 389                 return NULL;
 390         }
 391
 392         /* this is a gateway now, remove any tt entries */
 393         orig_node = batadv_orig_hash_find(bat_priv, orig);
 394         if (orig_node) {
 395                 batadv_tt_global_del_orig(bat_priv, orig_node,
 396                                           "became a backbone gateway");
 397                 batadv_orig_node_free_ref(orig_node);
 398         }
 399         return entry;
 400 }
 401
 402 /* update or add the own backbone gw to make sure we announce
 403  * where we receive other backbone gws
 404  */
 405 static void bla_update_own_backbone_gw(struct bat_priv *bat_priv,
 406                                        struct hard_iface *primary_if,
 407                                        short vid)
 408 {
 409         struct backbone_gw *backbone_gw;
 410
 411         backbone_gw = bla_get_backbone_gw(bat_priv,
 412                                           primary_if->net_dev->dev_addr, vid);
 413         if (unlikely(!backbone_gw))
 414                 return;
 415
 416         backbone_gw->lasttime = jiffies;
 417         backbone_gw_free_ref(backbone_gw);
 418 }
 419
 420 /* @bat_priv: the bat priv with all the soft interface information
 421  * @vid: the vid where the request came on
 422  *
 423  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 424  * to allow the requester another check if the CRC is correct now.
 425  */
 426 static void bla_answer_request(struct bat_priv *bat_priv,
 427                                struct hard_iface *primary_if, short vid)
 428 {
 429         struct hlist_node *node;
 430         struct hlist_head *head;
 431         struct hashtable_t *hash;
 432         struct claim *claim;
 433         struct backbone_gw *backbone_gw;
 434         int i;
 435
 436         bat_dbg(DBG_BLA, bat_priv,
 437                 "bla_answer_request(): received a claim request, send all of our own claims again\n");
 438
 439         backbone_gw = backbone_hash_find(bat_priv,
 440                                          primary_if->net_dev->dev_addr, vid);
 441         if (!backbone_gw)
 442                 return;
 443
 444         hash = bat_priv->claim_hash;
 445         for (i = 0; i < hash->size; i++) {
 446                 head = &hash->table[i];
 447
 448                 rcu_read_lock();
 449                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 450                         /* only own claims are interesting */
 451                         if (claim->backbone_gw != backbone_gw)
 452                                 continue;
 453
 454                         bla_send_claim(bat_priv, claim->addr, claim->vid,
 455                                        CLAIM_TYPE_ADD);
 456                 }
 457                 rcu_read_unlock();
 458         }
 459
 460         /* finally, send an announcement frame */
 461         bla_send_announce(bat_priv, backbone_gw);
 462         backbone_gw_free_ref(backbone_gw);
 463 }
 464
 465 /* @backbone_gw: the backbone gateway from whom we are out of sync
 466  *
 467  * When the crc is wrong, ask the backbone gateway for a full table update.
 468  * After the request, it will repeat all of his own claims and finally
 469  * send an announcement claim with which we can check again.
 470  */
 471 static void bla_send_request(struct backbone_gw *backbone_gw)
 472 {
 473         /* first, remove all old entries */
 474         bla_del_backbone_claims(backbone_gw);
 475
 476         bat_dbg(DBG_BLA, backbone_gw->bat_priv,
 477                 "Sending REQUEST to %pM\n",
 478                 backbone_gw->orig);
 479
 480         /* send request */
 481         bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 482                        backbone_gw->vid, CLAIM_TYPE_REQUEST);
 483
 484         /* no local broadcasts should be sent or received, for now. */
 485         if (!atomic_read(&backbone_gw->request_sent)) {
 486                 atomic_inc(&backbone_gw->bat_priv->bla_num_requests);
 487                 atomic_set(&backbone_gw->request_sent, 1);
 488         }
 489 }
 490
 491 /* @bat_priv: the bat priv with all the soft interface information
 492  * @backbone_gw: our backbone gateway which should be announced
 493  *
 494  * This function sends an announcement. It is called from multiple
 495  * places.
 496  */
 497 static void bla_send_announce(struct bat_priv *bat_priv,
 498                               struct backbone_gw *backbone_gw)
 499 {
 500         uint8_t mac[ETH_ALEN];
 501         __be16 crc;
 502
 503         memcpy(mac, announce_mac, 4);
 504         crc = htons(backbone_gw->crc);
 505         memcpy(&mac[4], &crc, 2);
 506
 507         bla_send_claim(bat_priv, mac, backbone_gw->vid, CLAIM_TYPE_ANNOUNCE);
 508
 509 }
 510
 511 /* @bat_priv: the bat priv with all the soft interface information
 512  * @mac: the mac address of the claim
 513  * @vid: the VLAN ID of the frame
 514  * @backbone_gw: the backbone gateway which claims it
 515  *
 516  * Adds a claim in the claim hash.
 517  */
 518 static void bla_add_claim(struct bat_priv *bat_priv, const uint8_t *mac,
 519                           const short vid, struct backbone_gw *backbone_gw)
 520 {
 521         struct claim *claim;
 522         struct claim search_claim;
 523         int hash_added;
 524
 525         memcpy(search_claim.addr, mac, ETH_ALEN);
 526         search_claim.vid = vid;
 527         claim = claim_hash_find(bat_priv, &search_claim);
 528
 529         /* create a new claim entry if it does not exist yet. */
 530         if (!claim) {
 531                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 532                 if (!claim)
 533                         return;
 534
 535                 memcpy(claim->addr, mac, ETH_ALEN);
 536                 claim->vid = vid;
 537                 claim->lasttime = jiffies;
 538                 claim->backbone_gw = backbone_gw;
 539
 540                 atomic_set(&claim->refcount, 2);
 541                 bat_dbg(DBG_BLA, bat_priv,
 542                         "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 543                         mac, vid);
 544                 hash_added = batadv_hash_add(bat_priv->claim_hash,
 545                                              compare_claim, choose_claim,
 546                                              claim, &claim->hash_entry);
 547
 548                 if (unlikely(hash_added != 0)) {
 549                         /* only local changes happened. */
 550                         kfree(claim);
 551                         return;
 552                 }
 553         } else {
 554                 claim->lasttime = jiffies;
 555                 if (claim->backbone_gw == backbone_gw)
 556                         /* no need to register a new backbone */
 557                         goto claim_free_ref;
 558
 559                 bat_dbg(DBG_BLA, bat_priv,
 560                         "bla_add_claim(): changing ownership for %pM, vid %d\n",
 561                         mac, vid);
 562
 563                 claim->backbone_gw->crc ^=
 564                         crc16(0, claim->addr, ETH_ALEN);
 565                 backbone_gw_free_ref(claim->backbone_gw);
 566
 567         }
 568         /* set (new) backbone gw */
 569         atomic_inc(&backbone_gw->refcount);
 570         claim->backbone_gw = backbone_gw;
 571
 572         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 573         backbone_gw->lasttime = jiffies;
 574
 575 claim_free_ref:
 576         claim_free_ref(claim);
 577 }
 578
 579 /* Delete a claim from the claim hash which has the
 580  * given mac address and vid.
 581  */
 582 static void bla_del_claim(struct bat_priv *bat_priv, const uint8_t *mac,
 583                           const short vid)
 584 {
 585         struct claim search_claim, *claim;
 586
 587         memcpy(search_claim.addr, mac, ETH_ALEN);
 588         search_claim.vid = vid;
 589         claim = claim_hash_find(bat_priv, &search_claim);
 590         if (!claim)
 591                 return;
 592
 593         bat_dbg(DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n", mac, vid);
 594
 595         batadv_hash_remove(bat_priv->claim_hash, compare_claim, choose_claim,
 596                            claim);
 597         claim_free_ref(claim); /* reference from the hash is gone */
 598
 599         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 600
 601         /* don't need the reference from hash_find() anymore */
 602         claim_free_ref(claim);
 603 }
 604
 605 /* check for ANNOUNCE frame, return 1 if handled */
 606 static int handle_announce(struct bat_priv *bat_priv,
 607                            uint8_t *an_addr, uint8_t *backbone_addr, short vid)
 608 {
 609         struct backbone_gw *backbone_gw;
 610         uint16_t crc;
 611
 612         if (memcmp(an_addr, announce_mac, 4) != 0)
 613                 return 0;
 614
 615         backbone_gw = bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 616
 617         if (unlikely(!backbone_gw))
 618                 return 1;
 619
 620
 621         /* handle as ANNOUNCE frame */
 622         backbone_gw->lasttime = jiffies;
 623         crc = ntohs(*((__be16 *)(&an_addr[4])));
 624
 625         bat_dbg(DBG_BLA, bat_priv,
 626                 "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %04x\n",
 627                 vid, backbone_gw->orig, crc);
 628
 629         if (backbone_gw->crc != crc) {
 630                 bat_dbg(DBG_BLA, backbone_gw->bat_priv,
 631                         "handle_announce(): CRC FAILED for %pM/%d (my = %04x, sent = %04x)\n",
 632                         backbone_gw->orig, backbone_gw->vid, backbone_gw->crc,
 633                         crc);
 634
 635                 bla_send_request(backbone_gw);
 636         } else {
 637                 /* if we have sent a request and the crc was OK,
 638                  * we can allow traffic again.
 639                  */
 640                 if (atomic_read(&backbone_gw->request_sent)) {
 641                         atomic_dec(&backbone_gw->bat_priv->bla_num_requests);
 642                         atomic_set(&backbone_gw->request_sent, 0);
 643                 }
 644         }
 645
 646         backbone_gw_free_ref(backbone_gw);
 647         return 1;
 648 }
 649
 650 /* check for REQUEST frame, return 1 if handled */
 651 static int handle_request(struct bat_priv *bat_priv,
 652                           struct hard_iface *primary_if,
 653                           uint8_t *backbone_addr,
 654                           struct ethhdr *ethhdr, short vid)
 655 {
 656         /* check for REQUEST frame */
 657         if (!compare_eth(backbone_addr, ethhdr->h_dest))
 658                 return 0;
 659
 660         /* sanity check, this should not happen on a normal switch,
 661          * we ignore it in this case.
 662          */
 663         if (!compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 664                 return 1;
 665
 666         bat_dbg(DBG_BLA, bat_priv,
 667                 "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 668                 vid, ethhdr->h_source);
 669
 670         bla_answer_request(bat_priv, primary_if, vid);
 671         return 1;
 672 }
 673
 674 /* check for UNCLAIM frame, return 1 if handled */
 675 static int handle_unclaim(struct bat_priv *bat_priv,
 676                           struct hard_iface *primary_if,
 677                           uint8_t *backbone_addr,
 678                           uint8_t *claim_addr, short vid)
 679 {
 680         struct backbone_gw *backbone_gw;
 681
 682         /* unclaim in any case if it is our own */
 683         if (primary_if && compare_eth(backbone_addr,
 684                                       primary_if->net_dev->dev_addr))
 685                 bla_send_claim(bat_priv, claim_addr, vid, CLAIM_TYPE_DEL);
 686
 687         backbone_gw = backbone_hash_find(bat_priv, backbone_addr, vid);
 688
 689         if (!backbone_gw)
 690                 return 1;
 691
 692         /* this must be an UNCLAIM frame */
 693         bat_dbg(DBG_BLA, bat_priv,
 694                 "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 695                 claim_addr, vid, backbone_gw->orig);
 696
 697         bla_del_claim(bat_priv, claim_addr, vid);
 698         backbone_gw_free_ref(backbone_gw);
 699         return 1;
 700 }
 701
 702 /* check for CLAIM frame, return 1 if handled */
 703 static int handle_claim(struct bat_priv *bat_priv,
 704                         struct hard_iface *primary_if, uint8_t *backbone_addr,
 705                         uint8_t *claim_addr, short vid)
 706 {
 707         struct backbone_gw *backbone_gw;
 708
 709         /* register the gateway if not yet available, and add the claim. */
 710
 711         backbone_gw = bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 712
 713         if (unlikely(!backbone_gw))
 714                 return 1;
 715
 716         /* this must be a CLAIM frame */
 717         bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 718         if (compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 719                 bla_send_claim(bat_priv, claim_addr, vid, CLAIM_TYPE_ADD);
 720
 721         /* TODO: we could call something like tt_local_del() here. */
 722
 723         backbone_gw_free_ref(backbone_gw);
 724         return 1;
 725 }
 726
 727 /* @bat_priv: the bat priv with all the soft interface information
 728  * @hw_src: the Hardware source in the ARP Header
 729  * @hw_dst: the Hardware destination in the ARP Header
 730  * @ethhdr: pointer to the Ethernet header of the claim frame
 731  *
 732  * checks if it is a claim packet and if its on the same group.
 733  * This function also applies the group ID of the sender
 734  * if it is in the same mesh.
 735  *
 736  * returns:
 737  *      2  - if it is a claim packet and on the same group
 738  *      1  - if is a claim packet from another group
 739  *      0  - if it is not a claim packet
 740  */
 741 static int check_claim_group(struct bat_priv *bat_priv,
 742                              struct hard_iface *primary_if,
 743                              uint8_t *hw_src, uint8_t *hw_dst,
 744                              struct ethhdr *ethhdr)
 745 {
 746         uint8_t *backbone_addr;
 747         struct orig_node *orig_node;
 748         struct bla_claim_dst *bla_dst, *bla_dst_own;
 749
 750         bla_dst = (struct bla_claim_dst *)hw_dst;
 751         bla_dst_own = &bat_priv->claim_dest;
 752
 753         /* check if it is a claim packet in general */
 754         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 755                    sizeof(bla_dst->magic)) != 0)
 756                 return 0;
 757
 758         /* if announcement packet, use the source,
 759          * otherwise assume it is in the hw_src
 760          */
 761         switch (bla_dst->type) {
 762         case CLAIM_TYPE_ADD:
 763                 backbone_addr = hw_src;
 764                 break;
 765         case CLAIM_TYPE_REQUEST:
 766         case CLAIM_TYPE_ANNOUNCE:
 767         case CLAIM_TYPE_DEL:
 768                 backbone_addr = ethhdr->h_source;
 769                 break;
 770         default:
 771                 return 0;
 772         }
 773
 774         /* don't accept claim frames from ourselves */
 775         if (compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 776                 return 0;
 777
 778         /* if its already the same group, it is fine. */
 779         if (bla_dst->group == bla_dst_own->group)
 780                 return 2;
 781
 782         /* lets see if this originator is in our mesh */
 783         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 784
 785         /* dont accept claims from gateways which are not in
 786          * the same mesh or group.
 787          */
 788         if (!orig_node)
 789                 return 1;
 790
 791         /* if our mesh friends mac is bigger, use it for ourselves. */
 792         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 793                 bat_dbg(DBG_BLA, bat_priv,
 794                         "taking other backbones claim group: %04x\n",
 795                         ntohs(bla_dst->group));
 796                 bla_dst_own->group = bla_dst->group;
 797         }
 798
 799         batadv_orig_node_free_ref(orig_node);
 800
 801         return 2;
 802 }
 803
 804
 805 /* @bat_priv: the bat priv with all the soft interface information
 806  * @skb: the frame to be checked
 807  *
 808  * Check if this is a claim frame, and process it accordingly.
 809  *
 810  * returns 1 if it was a claim frame, otherwise return 0 to
 811  * tell the callee that it can use the frame on its own.
 812  */
 813 static int bla_process_claim(struct bat_priv *bat_priv,
 814                              struct hard_iface *primary_if,
 815                              struct sk_buff *skb)
 816 {
 817         struct ethhdr *ethhdr;
 818         struct vlan_ethhdr *vhdr;
 819         struct arphdr *arphdr;
 820         uint8_t *hw_src, *hw_dst;
 821         struct bla_claim_dst *bla_dst;
 822         uint16_t proto;
 823         int headlen;
 824         short vid = -1;
 825         int ret;
 826
 827         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 828
 829         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 830                 vhdr = (struct vlan_ethhdr *)ethhdr;
 831                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
 832                 proto = ntohs(vhdr->h_vlan_encapsulated_proto);
 833                 headlen = sizeof(*vhdr);
 834         } else {
 835                 proto = ntohs(ethhdr->h_proto);
 836                 headlen = ETH_HLEN;
 837         }
 838
 839         if (proto != ETH_P_ARP)
 840                 return 0; /* not a claim frame */
 841
 842         /* this must be a ARP frame. check if it is a claim. */
 843
 844         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 845                 return 0;
 846
 847         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 848         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 849         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 850
 851         /* Check whether the ARP frame carries a valid
 852          * IP information
 853          */
 854         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 855                 return 0;
 856         if (arphdr->ar_pro != htons(ETH_P_IP))
 857                 return 0;
 858         if (arphdr->ar_hln != ETH_ALEN)
 859                 return 0;
 860         if (arphdr->ar_pln != 4)
 861                 return 0;
 862
 863         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 864         hw_dst = hw_src + ETH_ALEN + 4;
 865         bla_dst = (struct bla_claim_dst *)hw_dst;
 866
 867         /* check if it is a claim frame. */
 868         ret = check_claim_group(bat_priv, primary_if, hw_src, hw_dst, ethhdr);
 869         if (ret == 1)
 870                 bat_dbg(DBG_BLA, bat_priv,
 871                         "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 872                         ethhdr->h_source, vid, hw_src, hw_dst);
 873
 874         if (ret < 2)
 875                 return ret;
 876
 877         /* become a backbone gw ourselves on this vlan if not happened yet */
 878         bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 879
 880         /* check for the different types of claim frames ... */
 881         switch (bla_dst->type) {
 882         case CLAIM_TYPE_ADD:
 883                 if (handle_claim(bat_priv, primary_if, hw_src,
 884                                  ethhdr->h_source, vid))
 885                         return 1;
 886                 break;
 887         case CLAIM_TYPE_DEL:
 888                 if (handle_unclaim(bat_priv, primary_if,
 889                                    ethhdr->h_source, hw_src, vid))
 890                         return 1;
 891                 break;
 892
 893         case CLAIM_TYPE_ANNOUNCE:
 894                 if (handle_announce(bat_priv, hw_src, ethhdr->h_source, vid))
 895                         return 1;
 896                 break;
 897         case CLAIM_TYPE_REQUEST:
 898                 if (handle_request(bat_priv, primary_if, hw_src, ethhdr, vid))
 899                         return 1;
 900                 break;
 901         }
 902
 903         bat_dbg(DBG_BLA, bat_priv,
 904                 "bla_process_claim(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 905                 ethhdr->h_source, vid, hw_src, hw_dst);
 906         return 1;
 907 }
 908
 909 /* Check when we last heard from other nodes, and remove them in case of
 910  * a time out, or clean all backbone gws if now is set.
 911  */
 912 static void bla_purge_backbone_gw(struct bat_priv *bat_priv, int now)
 913 {
 914         struct backbone_gw *backbone_gw;
 915         struct hlist_node *node, *node_tmp;
 916         struct hlist_head *head;
 917         struct hashtable_t *hash;
 918         spinlock_t *list_lock;  /* protects write access to the hash lists */
 919         int i;
 920
 921         hash = bat_priv->backbone_hash;
 922         if (!hash)
 923                 return;
 924
 925         for (i = 0; i < hash->size; i++) {
 926                 head = &hash->table[i];
 927                 list_lock = &hash->list_locks[i];
 928
 929                 spin_lock_bh(list_lock);
 930                 hlist_for_each_entry_safe(backbone_gw, node, node_tmp,
 931                                           head, hash_entry) {
 932                         if (now)
 933                                 goto purge_now;
 934                         if (!has_timed_out(backbone_gw->lasttime,
 935                                            BLA_BACKBONE_TIMEOUT))
 936                                 continue;
 937
 938                         bat_dbg(DBG_BLA, backbone_gw->bat_priv,
 939                                 "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
 940                                 backbone_gw->orig);
 941
 942 purge_now:
 943                         /* don't wait for the pending request anymore */
 944                         if (atomic_read(&backbone_gw->request_sent))
 945                                 atomic_dec(&bat_priv->bla_num_requests);
 946
 947                         bla_del_backbone_claims(backbone_gw);
 948
 949                         hlist_del_rcu(node);
 950                         backbone_gw_free_ref(backbone_gw);
 951                 }
 952                 spin_unlock_bh(list_lock);
 953         }
 954 }
 955
 956 /* @bat_priv: the bat priv with all the soft interface information
 957  * @primary_if: the selected primary interface, may be NULL if now is set
 958  * @now: whether the whole hash shall be wiped now
 959  *
 960  * Check when we heard last time from our own claims, and remove them in case of
 961  * a time out, or clean all claims if now is set
 962  */
 963 static void bla_purge_claims(struct bat_priv *bat_priv,
 964                              struct hard_iface *primary_if, int now)
 965 {
 966         struct claim *claim;
 967         struct hlist_node *node;
 968         struct hlist_head *head;
 969         struct hashtable_t *hash;
 970         int i;
 971
 972         hash = bat_priv->claim_hash;
 973         if (!hash)
 974                 return;
 975
 976         for (i = 0; i < hash->size; i++) {
 977                 head = &hash->table[i];
 978
 979                 rcu_read_lock();
 980                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 981                         if (now)
 982                                 goto purge_now;
 983                         if (!compare_eth(claim->backbone_gw->orig,
 984                                          primary_if->net_dev->dev_addr))
 985                                 continue;
 986                         if (!has_timed_out(claim->lasttime,
 987                                            BLA_CLAIM_TIMEOUT))
 988                                 continue;
 989
 990                         bat_dbg(DBG_BLA, bat_priv,
 991                                 "bla_purge_claims(): %pM, vid %d, time out\n",
 992                                 claim->addr, claim->vid);
 993
 994 purge_now:
 995                         handle_unclaim(bat_priv, primary_if,
 996                                        claim->backbone_gw->orig,
 997                                        claim->addr, claim->vid);
 998                 }
 999                 rcu_read_unlock();
1000         }
1001 }
1002
1003 /* @bat_priv: the bat priv with all the soft interface information
1004  * @primary_if: the new selected primary_if
1005  * @oldif: the old primary interface, may be NULL
1006  *
1007  * Update the backbone gateways when the own orig address changes.
1008  */
1009 void batadv_bla_update_orig_address(struct bat_priv *bat_priv,
1010                                     struct hard_iface *primary_if,
1011                                     struct hard_iface *oldif)
1012 {
1013         struct backbone_gw *backbone_gw;
1014         struct hlist_node *node;
1015         struct hlist_head *head;
1016         struct hashtable_t *hash;
1017         int i;
1018
1019         /* reset bridge loop avoidance group id */
1020         bat_priv->claim_dest.group =
1021                 htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1022
1023         if (!oldif) {
1024                 bla_purge_claims(bat_priv, NULL, 1);
1025                 bla_purge_backbone_gw(bat_priv, 1);
1026                 return;
1027         }
1028
1029         hash = bat_priv->backbone_hash;
1030         if (!hash)
1031                 return;
1032
1033         for (i = 0; i < hash->size; i++) {
1034                 head = &hash->table[i];
1035
1036                 rcu_read_lock();
1037                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1038                         /* own orig still holds the old value. */
1039                         if (!compare_eth(backbone_gw->orig,
1040                                          oldif->net_dev->dev_addr))
1041                                 continue;
1042
1043                         memcpy(backbone_gw->orig,
1044                                primary_if->net_dev->dev_addr, ETH_ALEN);
1045                         /* send an announce frame so others will ask for our
1046                          * claims and update their tables.
1047                          */
1048                         bla_send_announce(bat_priv, backbone_gw);
1049                 }
1050                 rcu_read_unlock();
1051         }
1052 }
1053
1054
1055
1056 /* (re)start the timer */
1057 static void bla_start_timer(struct bat_priv *bat_priv)
1058 {
1059         INIT_DELAYED_WORK(&bat_priv->bla_work, bla_periodic_work);
1060         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla_work,
1061                            msecs_to_jiffies(BLA_PERIOD_LENGTH));
1062 }
1063
1064 /* periodic work to do:
1065  *  * purge structures when they are too old
1066  *  * send announcements
1067  */
1068 static void bla_periodic_work(struct work_struct *work)
1069 {
1070         struct delayed_work *delayed_work =
1071                 container_of(work, struct delayed_work, work);
1072         struct bat_priv *bat_priv =
1073                 container_of(delayed_work, struct bat_priv, bla_work);
1074         struct hlist_node *node;
1075         struct hlist_head *head;
1076         struct backbone_gw *backbone_gw;
1077         struct hashtable_t *hash;
1078         struct hard_iface *primary_if;
1079         int i;
1080
1081         primary_if = batadv_primary_if_get_selected(bat_priv);
1082         if (!primary_if)
1083                 goto out;
1084
1085         bla_purge_claims(bat_priv, primary_if, 0);
1086         bla_purge_backbone_gw(bat_priv, 0);
1087
1088         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1089                 goto out;
1090
1091         hash = bat_priv->backbone_hash;
1092         if (!hash)
1093                 goto out;
1094
1095         for (i = 0; i < hash->size; i++) {
1096                 head = &hash->table[i];
1097
1098                 rcu_read_lock();
1099                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1100                         if (!compare_eth(backbone_gw->orig,
1101                                          primary_if->net_dev->dev_addr))
1102                                 continue;
1103
1104                         backbone_gw->lasttime = jiffies;
1105
1106                         bla_send_announce(bat_priv, backbone_gw);
1107                 }
1108                 rcu_read_unlock();
1109         }
1110 out:
1111         if (primary_if)
1112                 batadv_hardif_free_ref(primary_if);
1113
1114         bla_start_timer(bat_priv);
1115 }
1116
1117 /* The hash for claim and backbone hash receive the same key because they
1118  * are getting initialized by hash_new with the same key. Reinitializing
1119  * them with to different keys to allow nested locking without generating
1120  * lockdep warnings
1121  */
1122 static struct lock_class_key claim_hash_lock_class_key;
1123 static struct lock_class_key backbone_hash_lock_class_key;
1124
1125 /* initialize all bla structures */
1126 int batadv_bla_init(struct bat_priv *bat_priv)
1127 {
1128         int i;
1129         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1130         struct hard_iface *primary_if;
1131
1132         bat_dbg(DBG_BLA, bat_priv, "bla hash registering\n");
1133
1134         /* setting claim destination address */
1135         memcpy(&bat_priv->claim_dest.magic, claim_dest, 3);
1136         bat_priv->claim_dest.type = 0;
1137         primary_if = batadv_primary_if_get_selected(bat_priv);
1138         if (primary_if) {
1139                 bat_priv->claim_dest.group =
1140                         htons(crc16(0, primary_if->net_dev->dev_addr,
1141                                     ETH_ALEN));
1142                 batadv_hardif_free_ref(primary_if);
1143         } else {
1144                 bat_priv->claim_dest.group = 0; /* will be set later */
1145         }
1146
1147         /* initialize the duplicate list */
1148         for (i = 0; i < DUPLIST_SIZE; i++)
1149                 bat_priv->bcast_duplist[i].entrytime =
1150                         jiffies - msecs_to_jiffies(DUPLIST_TIMEOUT);
1151         bat_priv->bcast_duplist_curr = 0;
1152
1153         if (bat_priv->claim_hash)
1154                 return 0;
1155
1156         bat_priv->claim_hash = batadv_hash_new(128);
1157         bat_priv->backbone_hash = batadv_hash_new(32);
1158
1159         if (!bat_priv->claim_hash || !bat_priv->backbone_hash)
1160                 return -ENOMEM;
1161
1162         batadv_hash_set_lock_class(bat_priv->claim_hash,
1163                                    &claim_hash_lock_class_key);
1164         batadv_hash_set_lock_class(bat_priv->backbone_hash,
1165                                    &backbone_hash_lock_class_key);
1166
1167         bat_dbg(DBG_BLA, bat_priv, "bla hashes initialized\n");
1168
1169         bla_start_timer(bat_priv);
1170         return 0;
1171 }
1172
1173 /* @bat_priv: the bat priv with all the soft interface information
1174  * @bcast_packet: originator mac address
1175  * @hdr_size: maximum length of the frame
1176  *
1177  * check if it is on our broadcast list. Another gateway might
1178  * have sent the same packet because it is connected to the same backbone,
1179  * so we have to remove this duplicate.
1180  *
1181  * This is performed by checking the CRC, which will tell us
1182  * with a good chance that it is the same packet. If it is furthermore
1183  * sent by another host, drop it. We allow equal packets from
1184  * the same host however as this might be intended.
1185  */
1186 int batadv_bla_check_bcast_duplist(struct bat_priv *bat_priv,
1187                                    struct bcast_packet *bcast_packet,
1188                                    int hdr_size)
1189 {
1190         int i, length, curr;
1191         uint8_t *content;
1192         uint16_t crc;
1193         struct bcast_duplist_entry *entry;
1194
1195         length = hdr_size - sizeof(*bcast_packet);
1196         content = (uint8_t *)bcast_packet;
1197         content += sizeof(*bcast_packet);
1198
1199         /* calculate the crc ... */
1200         crc = crc16(0, content, length);
1201
1202         for (i = 0 ; i < DUPLIST_SIZE; i++) {
1203                 curr = (bat_priv->bcast_duplist_curr + i) % DUPLIST_SIZE;
1204                 entry = &bat_priv->bcast_duplist[curr];
1205
1206                 /* we can stop searching if the entry is too old ;
1207                  * later entries will be even older
1208                  */
1209                 if (has_timed_out(entry->entrytime, DUPLIST_TIMEOUT))
1210                         break;
1211
1212                 if (entry->crc != crc)
1213                         continue;
1214
1215                 if (compare_eth(entry->orig, bcast_packet->orig))
1216                         continue;
1217
1218                 /* this entry seems to match: same crc, not too old,
1219                  * and from another gw. therefore return 1 to forbid it.
1220                  */
1221                 return 1;
1222         }
1223         /* not found, add a new entry (overwrite the oldest entry) */
1224         curr = (bat_priv->bcast_duplist_curr + DUPLIST_SIZE - 1) % DUPLIST_SIZE;
1225         entry = &bat_priv->bcast_duplist[curr];
1226         entry->crc = crc;
1227         entry->entrytime = jiffies;
1228         memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
1229         bat_priv->bcast_duplist_curr = curr;
1230
1231         /* allow it, its the first occurence. */
1232         return 0;
1233 }
1234
1235
1236
1237 /* @bat_priv: the bat priv with all the soft interface information
1238  * @orig: originator mac address
1239  *
1240  * check if the originator is a gateway for any VLAN ID.
1241  *
1242  * returns 1 if it is found, 0 otherwise
1243  */
1244 int batadv_bla_is_backbone_gw_orig(struct bat_priv *bat_priv, uint8_t *orig)
1245 {
1246         struct hashtable_t *hash = bat_priv->backbone_hash;
1247         struct hlist_head *head;
1248         struct hlist_node *node;
1249         struct backbone_gw *backbone_gw;
1250         int i;
1251
1252         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1253                 return 0;
1254
1255         if (!hash)
1256                 return 0;
1257
1258         for (i = 0; i < hash->size; i++) {
1259                 head = &hash->table[i];
1260
1261                 rcu_read_lock();
1262                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1263                         if (compare_eth(backbone_gw->orig, orig)) {
1264                                 rcu_read_unlock();
1265                                 return 1;
1266                         }
1267                 }
1268                 rcu_read_unlock();
1269         }
1270
1271         return 0;
1272 }
1273
1274
1275 /* @skb: the frame to be checked
1276  * @orig_node: the orig_node of the frame
1277  * @hdr_size: maximum length of the frame
1278  *
1279  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1280  * if the orig_node is also a gateway on the soft interface, otherwise it
1281  * returns 0.
1282  */
1283 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1284                               struct orig_node *orig_node, int hdr_size)
1285 {
1286         struct ethhdr *ethhdr;
1287         struct vlan_ethhdr *vhdr;
1288         struct backbone_gw *backbone_gw;
1289         short vid = -1;
1290
1291         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1292                 return 0;
1293
1294         /* first, find out the vid. */
1295         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1296                 return 0;
1297
1298         ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);
1299
1300         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
1301                 if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
1302                         return 0;
1303
1304                 vhdr = (struct vlan_ethhdr *)(((uint8_t *)skb->data) +
1305                                               hdr_size);
1306                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
1307         }
1308
1309         /* see if this originator is a backbone gw for this VLAN */
1310         backbone_gw = backbone_hash_find(orig_node->bat_priv,
1311                                          orig_node->orig, vid);
1312         if (!backbone_gw)
1313                 return 0;
1314
1315         backbone_gw_free_ref(backbone_gw);
1316         return 1;
1317 }
1318
1319 /* free all bla structures (for softinterface free or module unload) */
1320 void batadv_bla_free(struct bat_priv *bat_priv)
1321 {
1322         struct hard_iface *primary_if;
1323
1324         cancel_delayed_work_sync(&bat_priv->bla_work);
1325         primary_if = batadv_primary_if_get_selected(bat_priv);
1326
1327         if (bat_priv->claim_hash) {
1328                 bla_purge_claims(bat_priv, primary_if, 1);
1329                 batadv_hash_destroy(bat_priv->claim_hash);
1330                 bat_priv->claim_hash = NULL;
1331         }
1332         if (bat_priv->backbone_hash) {
1333                 bla_purge_backbone_gw(bat_priv, 1);
1334                 batadv_hash_destroy(bat_priv->backbone_hash);
1335                 bat_priv->backbone_hash = NULL;
1336         }
1337         if (primary_if)
1338                 batadv_hardif_free_ref(primary_if);
1339 }
1340
1341 /* @bat_priv: the bat priv with all the soft interface information
1342  * @skb: the frame to be checked
1343  * @vid: the VLAN ID of the frame
1344  *
1345  * bla_rx avoidance checks if:
1346  *  * we have to race for a claim
1347  *  * if the frame is allowed on the LAN
1348  *
1349  * in these cases, the skb is further handled by this function and
1350  * returns 1, otherwise it returns 0 and the caller shall further
1351  * process the skb.
1352  */
1353 int batadv_bla_rx(struct bat_priv *bat_priv, struct sk_buff *skb, short vid)
1354 {
1355         struct ethhdr *ethhdr;
1356         struct claim search_claim, *claim = NULL;
1357         struct hard_iface *primary_if;
1358         int ret;
1359
1360         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1361
1362         primary_if = batadv_primary_if_get_selected(bat_priv);
1363         if (!primary_if)
1364                 goto handled;
1365
1366         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1367                 goto allow;
1368
1369
1370         if (unlikely(atomic_read(&bat_priv->bla_num_requests)))
1371                 /* don't allow broadcasts while requests are in flight */
1372                 if (is_multicast_ether_addr(ethhdr->h_dest))
1373                         goto handled;
1374
1375         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1376         search_claim.vid = vid;
1377         claim = claim_hash_find(bat_priv, &search_claim);
1378
1379         if (!claim) {
1380                 /* possible optimization: race for a claim */
1381                 /* No claim exists yet, claim it for us!
1382                  */
1383                 handle_claim(bat_priv, primary_if,
1384                              primary_if->net_dev->dev_addr,
1385                              ethhdr->h_source, vid);
1386                 goto allow;
1387         }
1388
1389         /* if it is our own claim ... */
1390         if (compare_eth(claim->backbone_gw->orig,
1391                         primary_if->net_dev->dev_addr)) {
1392                 /* ... allow it in any case */
1393                 claim->lasttime = jiffies;
1394                 goto allow;
1395         }
1396
1397         /* if it is a broadcast ... */
1398         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1399                 /* ... drop it. the responsible gateway is in charge. */
1400                 goto handled;
1401         } else {
1402                 /* seems the client considers us as its best gateway.
1403                  * send a claim and update the claim table
1404                  * immediately.
1405                  */
1406                 handle_claim(bat_priv, primary_if,
1407                              primary_if->net_dev->dev_addr,
1408                              ethhdr->h_source, vid);
1409                 goto allow;
1410         }
1411 allow:
1412         bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1413         ret = 0;
1414         goto out;
1415
1416 handled:
1417         kfree_skb(skb);
1418         ret = 1;
1419
1420 out:
1421         if (primary_if)
1422                 batadv_hardif_free_ref(primary_if);
1423         if (claim)
1424                 claim_free_ref(claim);
1425         return ret;
1426 }
1427
1428 /* @bat_priv: the bat priv with all the soft interface information
1429  * @skb: the frame to be checked
1430  * @vid: the VLAN ID of the frame
1431  *
1432  * bla_tx checks if:
1433  *  * a claim was received which has to be processed
1434  *  * the frame is allowed on the mesh
1435  *
1436  * in these cases, the skb is further handled by this function and
1437  * returns 1, otherwise it returns 0 and the caller shall further
1438  * process the skb.
1439  */
1440 int batadv_bla_tx(struct bat_priv *bat_priv, struct sk_buff *skb, short vid)
1441 {
1442         struct ethhdr *ethhdr;
1443         struct claim search_claim, *claim = NULL;
1444         struct hard_iface *primary_if;
1445         int ret = 0;
1446
1447         primary_if = batadv_primary_if_get_selected(bat_priv);
1448         if (!primary_if)
1449                 goto out;
1450
1451         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1452                 goto allow;
1453
1454         /* in VLAN case, the mac header might not be set. */
1455         skb_reset_mac_header(skb);
1456
1457         if (bla_process_claim(bat_priv, primary_if, skb))
1458                 goto handled;
1459
1460         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1461
1462         if (unlikely(atomic_read(&bat_priv->bla_num_requests)))
1463                 /* don't allow broadcasts while requests are in flight */
1464                 if (is_multicast_ether_addr(ethhdr->h_dest))
1465                         goto handled;
1466
1467         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1468         search_claim.vid = vid;
1469
1470         claim = claim_hash_find(bat_priv, &search_claim);
1471
1472         /* if no claim exists, allow it. */
1473         if (!claim)
1474                 goto allow;
1475
1476         /* check if we are responsible. */
1477         if (compare_eth(claim->backbone_gw->orig,
1478                         primary_if->net_dev->dev_addr)) {
1479                 /* if yes, the client has roamed and we have
1480                  * to unclaim it.
1481                  */
1482                 handle_unclaim(bat_priv, primary_if,
1483                                primary_if->net_dev->dev_addr,
1484                                ethhdr->h_source, vid);
1485                 goto allow;
1486         }
1487
1488         /* check if it is a multicast/broadcast frame */
1489         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1490                 /* drop it. the responsible gateway has forwarded it into
1491                  * the backbone network.
1492                  */
1493                 goto handled;
1494         } else {
1495                 /* we must allow it. at least if we are
1496                  * responsible for the DESTINATION.
1497                  */
1498                 goto allow;
1499         }
1500 allow:
1501         bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1502         ret = 0;
1503         goto out;
1504 handled:
1505         ret = 1;
1506 out:
1507         if (primary_if)
1508                 batadv_hardif_free_ref(primary_if);
1509         if (claim)
1510                 claim_free_ref(claim);
1511         return ret;
1512 }
1513
1514 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1515 {
1516         struct net_device *net_dev = (struct net_device *)seq->private;
1517         struct bat_priv *bat_priv = netdev_priv(net_dev);
1518         struct hashtable_t *hash = bat_priv->claim_hash;
1519         struct claim *claim;
1520         struct hard_iface *primary_if;
1521         struct hlist_node *node;
1522         struct hlist_head *head;
1523         uint32_t i;
1524         bool is_own;
1525         int ret = 0;
1526
1527         primary_if = batadv_primary_if_get_selected(bat_priv);
1528         if (!primary_if) {
1529                 ret = seq_printf(seq,
1530                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
1531                                  net_dev->name);
1532                 goto out;
1533         }
1534
1535         if (primary_if->if_status != IF_ACTIVE) {
1536                 ret = seq_printf(seq,
1537                                  "BATMAN mesh %s disabled - primary interface not active\n",
1538                                  net_dev->name);
1539                 goto out;
1540         }
1541
1542         seq_printf(seq,
1543                    "Claims announced for the mesh %s (orig %pM, group id %04x)\n",
1544                    net_dev->name, primary_if->net_dev->dev_addr,
1545                    ntohs(bat_priv->claim_dest.group));
1546         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-4s)\n",
1547                    "Client", "VID", "Originator", "CRC");
1548         for (i = 0; i < hash->size; i++) {
1549                 head = &hash->table[i];
1550
1551                 rcu_read_lock();
1552                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1553                         is_own = compare_eth(claim->backbone_gw->orig,
1554                                              primary_if->net_dev->dev_addr);
1555                         seq_printf(seq, " * %pM on % 5d by %pM [%c] (%04x)\n",
1556                                    claim->addr, claim->vid,
1557                                    claim->backbone_gw->orig,
1558                                    (is_own ? 'x' : ' '),
1559                                    claim->backbone_gw->crc);
1560                 }
1561                 rcu_read_unlock();
1562         }
1563 out:
1564         if (primary_if)
1565                 batadv_hardif_free_ref(primary_if);
1566         return ret;
1567 }