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 batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
  35
  36 static void batadv_bla_periodic_work(struct work_struct *work);
  37 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
  38                                      struct batadv_backbone_gw *backbone_gw);
  39
  40 /* return the index of the claim */
  41 static inline uint32_t batadv_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 batadv_choose_backbone_gw(const void *data,
  62                                                  uint32_t size)
  63 {
  64         const unsigned char *key = data;
  65         uint32_t hash = 0;
  66         size_t i;
  67
  68         for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
  69                 hash += key[i];
  70                 hash += (hash << 10);
  71                 hash ^= (hash >> 6);
  72         }
  73
  74         hash += (hash << 3);
  75         hash ^= (hash >> 11);
  76         hash += (hash << 15);
  77
  78         return hash % size;
  79 }
  80
  81
  82 /* compares address and vid of two backbone gws */
  83 static int batadv_compare_backbone_gw(const struct hlist_node *node,
  84                                       const void *data2)
  85 {
  86         const void *data1 = container_of(node, struct batadv_backbone_gw,
  87                                          hash_entry);
  88
  89         return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
  90 }
  91
  92 /* compares address and vid of two claims */
  93 static int batadv_compare_claim(const struct hlist_node *node,
  94                                 const void *data2)
  95 {
  96         const void *data1 = container_of(node, struct batadv_claim,
  97                                          hash_entry);
  98
  99         return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
 100 }
 101
 102 /* free a backbone gw */
 103 static void batadv_backbone_gw_free_ref(struct batadv_backbone_gw *backbone_gw)
 104 {
 105         if (atomic_dec_and_test(&backbone_gw->refcount))
 106                 kfree_rcu(backbone_gw, rcu);
 107 }
 108
 109 /* finally deinitialize the claim */
 110 static void batadv_claim_free_rcu(struct rcu_head *rcu)
 111 {
 112         struct batadv_claim *claim;
 113
 114         claim = container_of(rcu, struct batadv_claim, rcu);
 115
 116         batadv_backbone_gw_free_ref(claim->backbone_gw);
 117         kfree(claim);
 118 }
 119
 120 /* free a claim, call claim_free_rcu if its the last reference */
 121 static void batadv_claim_free_ref(struct batadv_claim *claim)
 122 {
 123         if (atomic_dec_and_test(&claim->refcount))
 124                 call_rcu(&claim->rcu, batadv_claim_free_rcu);
 125 }
 126
 127 /* @bat_priv: the bat priv with all the soft interface information
 128  * @data: search data (may be local/static data)
 129  *
 130  * looks for a claim in the hash, and returns it if found
 131  * or NULL otherwise.
 132  */
 133 static struct batadv_claim *batadv_claim_hash_find(struct batadv_priv *bat_priv,
 134                                                    struct batadv_claim *data)
 135 {
 136         struct batadv_hashtable *hash = bat_priv->claim_hash;
 137         struct hlist_head *head;
 138         struct hlist_node *node;
 139         struct batadv_claim *claim;
 140         struct batadv_claim *claim_tmp = NULL;
 141         int index;
 142
 143         if (!hash)
 144                 return NULL;
 145
 146         index = batadv_choose_claim(data, hash->size);
 147         head = &hash->table[index];
 148
 149         rcu_read_lock();
 150         hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 151                 if (!batadv_compare_claim(&claim->hash_entry, data))
 152                         continue;
 153
 154                 if (!atomic_inc_not_zero(&claim->refcount))
 155                         continue;
 156
 157                 claim_tmp = claim;
 158                 break;
 159         }
 160         rcu_read_unlock();
 161
 162         return claim_tmp;
 163 }
 164
 165 /**
 166  * batadv_backbone_hash_find - looks for a claim in the hash
 167  * @bat_priv: the bat priv with all the soft interface information
 168  * @addr: the address of the originator
 169  * @vid: the VLAN ID
 170  *
 171  * Returns claim if found or NULL otherwise.
 172  */
 173 static struct batadv_backbone_gw *
 174 batadv_backbone_hash_find(struct batadv_priv *bat_priv,
 175                           uint8_t *addr, short vid)
 176 {
 177         struct batadv_hashtable *hash = bat_priv->backbone_hash;
 178         struct hlist_head *head;
 179         struct hlist_node *node;
 180         struct batadv_backbone_gw search_entry, *backbone_gw;
 181         struct batadv_backbone_gw *backbone_gw_tmp = NULL;
 182         int index;
 183
 184         if (!hash)
 185                 return NULL;
 186
 187         memcpy(search_entry.orig, addr, ETH_ALEN);
 188         search_entry.vid = vid;
 189
 190         index = batadv_choose_backbone_gw(&search_entry, hash->size);
 191         head = &hash->table[index];
 192
 193         rcu_read_lock();
 194         hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
 195                 if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
 196                                                 &search_entry))
 197                         continue;
 198
 199                 if (!atomic_inc_not_zero(&backbone_gw->refcount))
 200                         continue;
 201
 202                 backbone_gw_tmp = backbone_gw;
 203                 break;
 204         }
 205         rcu_read_unlock();
 206
 207         return backbone_gw_tmp;
 208 }
 209
 210 /* delete all claims for a backbone */
 211 static void
 212 batadv_bla_del_backbone_claims(struct batadv_backbone_gw *backbone_gw)
 213 {
 214         struct batadv_hashtable *hash;
 215         struct hlist_node *node, *node_tmp;
 216         struct hlist_head *head;
 217         struct batadv_claim *claim;
 218         int i;
 219         spinlock_t *list_lock;  /* protects write access to the hash lists */
 220
 221         hash = backbone_gw->bat_priv->claim_hash;
 222         if (!hash)
 223                 return;
 224
 225         for (i = 0; i < hash->size; i++) {
 226                 head = &hash->table[i];
 227                 list_lock = &hash->list_locks[i];
 228
 229                 spin_lock_bh(list_lock);
 230                 hlist_for_each_entry_safe(claim, node, node_tmp,
 231                                           head, hash_entry) {
 232
 233                         if (claim->backbone_gw != backbone_gw)
 234                                 continue;
 235
 236                         batadv_claim_free_ref(claim);
 237                         hlist_del_rcu(node);
 238                 }
 239                 spin_unlock_bh(list_lock);
 240         }
 241
 242         /* all claims gone, intialize CRC */
 243         backbone_gw->crc = BATADV_BLA_CRC_INIT;
 244 }
 245
 246 /**
 247  * batadv_bla_send_claim - sends a claim frame according to the provided info
 248  * @bat_priv: the bat priv with all the soft interface information
 249  * @orig: the mac address to be announced within the claim
 250  * @vid: the VLAN ID
 251  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 252  */
 253 static void batadv_bla_send_claim(struct batadv_priv *bat_priv, uint8_t *mac,
 254                                   short vid, int claimtype)
 255 {
 256         struct sk_buff *skb;
 257         struct ethhdr *ethhdr;
 258         struct batadv_hard_iface *primary_if;
 259         struct net_device *soft_iface;
 260         uint8_t *hw_src;
 261         struct batadv_bla_claim_dst local_claim_dest;
 262         __be32 zeroip = 0;
 263
 264         primary_if = batadv_primary_if_get_selected(bat_priv);
 265         if (!primary_if)
 266                 return;
 267
 268         memcpy(&local_claim_dest, &bat_priv->claim_dest,
 269                sizeof(local_claim_dest));
 270         local_claim_dest.type = claimtype;
 271
 272         soft_iface = primary_if->soft_iface;
 273
 274         skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
 275                          /* IP DST: 0.0.0.0 */
 276                          zeroip,
 277                          primary_if->soft_iface,
 278                          /* IP SRC: 0.0.0.0 */
 279                          zeroip,
 280                          /* Ethernet DST: Broadcast */
 281                          NULL,
 282                          /* Ethernet SRC/HW SRC:  originator mac */
 283                          primary_if->net_dev->dev_addr,
 284                          /* HW DST: FF:43:05:XX:00:00
 285                           * with XX   = claim type
 286                           * and YY:YY = group id
 287                           */
 288                          (uint8_t *)&local_claim_dest);
 289
 290         if (!skb)
 291                 goto out;
 292
 293         ethhdr = (struct ethhdr *)skb->data;
 294         hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
 295
 296         /* now we pretend that the client would have sent this ... */
 297         switch (claimtype) {
 298         case BATADV_CLAIM_TYPE_ADD:
 299                 /* normal claim frame
 300                  * set Ethernet SRC to the clients mac
 301                  */
 302                 memcpy(ethhdr->h_source, mac, ETH_ALEN);
 303                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 304                            "bla_send_claim(): CLAIM %pM on vid %d\n", mac, vid);
 305                 break;
 306         case BATADV_CLAIM_TYPE_DEL:
 307                 /* unclaim frame
 308                  * set HW SRC to the clients mac
 309                  */
 310                 memcpy(hw_src, mac, ETH_ALEN);
 311                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 312                            "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
 313                            vid);
 314                 break;
 315         case BATADV_CLAIM_TYPE_ANNOUNCE:
 316                 /* announcement frame
 317                  * set HW SRC to the special mac containg the crc
 318                  */
 319                 memcpy(hw_src, mac, ETH_ALEN);
 320                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 321                            "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
 322                            ethhdr->h_source, vid);
 323                 break;
 324         case BATADV_CLAIM_TYPE_REQUEST:
 325                 /* request frame
 326                  * set HW SRC to the special mac containg the crc
 327                  */
 328                 memcpy(hw_src, mac, ETH_ALEN);
 329                 memcpy(ethhdr->h_dest, mac, ETH_ALEN);
 330                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 331                            "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
 332                            ethhdr->h_source, ethhdr->h_dest, vid);
 333                 break;
 334
 335         }
 336
 337         if (vid != -1)
 338                 skb = vlan_insert_tag(skb, vid);
 339
 340         skb_reset_mac_header(skb);
 341         skb->protocol = eth_type_trans(skb, soft_iface);
 342         bat_priv->stats.rx_packets++;
 343         bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;
 344         soft_iface->last_rx = jiffies;
 345
 346         netif_rx(skb);
 347 out:
 348         if (primary_if)
 349                 batadv_hardif_free_ref(primary_if);
 350 }
 351
 352 /**
 353  * batadv_bla_get_backbone_gw
 354  * @bat_priv: the bat priv with all the soft interface information
 355  * @orig: the mac address of the originator
 356  * @vid: the VLAN ID
 357  *
 358  * searches for the backbone gw or creates a new one if it could not
 359  * be found.
 360  */
 361 static struct batadv_backbone_gw *
 362 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 363                            short vid)
 364 {
 365         struct batadv_backbone_gw *entry;
 366         struct batadv_orig_node *orig_node;
 367         int hash_added;
 368
 369         entry = batadv_backbone_hash_find(bat_priv, orig, vid);
 370
 371         if (entry)
 372                 return entry;
 373
 374         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 375                    "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 376                    orig, vid);
 377
 378         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 379         if (!entry)
 380                 return NULL;
 381
 382         entry->vid = vid;
 383         entry->lasttime = jiffies;
 384         entry->crc = BATADV_BLA_CRC_INIT;
 385         entry->bat_priv = bat_priv;
 386         atomic_set(&entry->request_sent, 0);
 387         memcpy(entry->orig, orig, ETH_ALEN);
 388
 389         /* one for the hash, one for returning */
 390         atomic_set(&entry->refcount, 2);
 391
 392         hash_added = batadv_hash_add(bat_priv->backbone_hash,
 393                                      batadv_compare_backbone_gw,
 394                                      batadv_choose_backbone_gw, entry,
 395                                      &entry->hash_entry);
 396
 397         if (unlikely(hash_added != 0)) {
 398                 /* hash failed, free the structure */
 399                 kfree(entry);
 400                 return NULL;
 401         }
 402
 403         /* this is a gateway now, remove any tt entries */
 404         orig_node = batadv_orig_hash_find(bat_priv, orig);
 405         if (orig_node) {
 406                 batadv_tt_global_del_orig(bat_priv, orig_node,
 407                                           "became a backbone gateway");
 408                 batadv_orig_node_free_ref(orig_node);
 409         }
 410         return entry;
 411 }
 412
 413 /* update or add the own backbone gw to make sure we announce
 414  * where we receive other backbone gws
 415  */
 416 static void
 417 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 418                                   struct batadv_hard_iface *primary_if,
 419                                   short vid)
 420 {
 421         struct batadv_backbone_gw *backbone_gw;
 422
 423         backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 424                                                  primary_if->net_dev->dev_addr,
 425                                                  vid);
 426         if (unlikely(!backbone_gw))
 427                 return;
 428
 429         backbone_gw->lasttime = jiffies;
 430         batadv_backbone_gw_free_ref(backbone_gw);
 431 }
 432
 433 /* @bat_priv: the bat priv with all the soft interface information
 434  * @vid: the vid where the request came on
 435  *
 436  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 437  * to allow the requester another check if the CRC is correct now.
 438  */
 439 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
 440                                       struct batadv_hard_iface *primary_if,
 441                                       short vid)
 442 {
 443         struct hlist_node *node;
 444         struct hlist_head *head;
 445         struct batadv_hashtable *hash;
 446         struct batadv_claim *claim;
 447         struct batadv_backbone_gw *backbone_gw;
 448         int i;
 449
 450         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 451                    "bla_answer_request(): received a claim request, send all of our own claims again\n");
 452
 453         backbone_gw = batadv_backbone_hash_find(bat_priv,
 454                                                 primary_if->net_dev->dev_addr,
 455                                                 vid);
 456         if (!backbone_gw)
 457                 return;
 458
 459         hash = bat_priv->claim_hash;
 460         for (i = 0; i < hash->size; i++) {
 461                 head = &hash->table[i];
 462
 463                 rcu_read_lock();
 464                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 465                         /* only own claims are interesting */
 466                         if (claim->backbone_gw != backbone_gw)
 467                                 continue;
 468
 469                         batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
 470                                               BATADV_CLAIM_TYPE_ADD);
 471                 }
 472                 rcu_read_unlock();
 473         }
 474
 475         /* finally, send an announcement frame */
 476         batadv_bla_send_announce(bat_priv, backbone_gw);
 477         batadv_backbone_gw_free_ref(backbone_gw);
 478 }
 479
 480 /* @backbone_gw: the backbone gateway from whom we are out of sync
 481  *
 482  * When the crc is wrong, ask the backbone gateway for a full table update.
 483  * After the request, it will repeat all of his own claims and finally
 484  * send an announcement claim with which we can check again.
 485  */
 486 static void batadv_bla_send_request(struct batadv_backbone_gw *backbone_gw)
 487 {
 488         /* first, remove all old entries */
 489         batadv_bla_del_backbone_claims(backbone_gw);
 490
 491         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 492                    "Sending REQUEST to %pM\n", backbone_gw->orig);
 493
 494         /* send request */
 495         batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 496                               backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
 497
 498         /* no local broadcasts should be sent or received, for now. */
 499         if (!atomic_read(&backbone_gw->request_sent)) {
 500                 atomic_inc(&backbone_gw->bat_priv->bla_num_requests);
 501                 atomic_set(&backbone_gw->request_sent, 1);
 502         }
 503 }
 504
 505 /* @bat_priv: the bat priv with all the soft interface information
 506  * @backbone_gw: our backbone gateway which should be announced
 507  *
 508  * This function sends an announcement. It is called from multiple
 509  * places.
 510  */
 511 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 512                                      struct batadv_backbone_gw *backbone_gw)
 513 {
 514         uint8_t mac[ETH_ALEN];
 515         __be16 crc;
 516
 517         memcpy(mac, batadv_announce_mac, 4);
 518         crc = htons(backbone_gw->crc);
 519         memcpy(&mac[4], &crc, 2);
 520
 521         batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
 522                               BATADV_CLAIM_TYPE_ANNOUNCE);
 523
 524 }
 525
 526 /**
 527  * batadv_bla_add_claim - Adds a claim in the claim hash
 528  * @bat_priv: the bat priv with all the soft interface information
 529  * @mac: the mac address of the claim
 530  * @vid: the VLAN ID of the frame
 531  * @backbone_gw: the backbone gateway which claims it
 532  */
 533 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
 534                                  const uint8_t *mac, const short vid,
 535                                  struct batadv_backbone_gw *backbone_gw)
 536 {
 537         struct batadv_claim *claim;
 538         struct batadv_claim search_claim;
 539         int hash_added;
 540
 541         memcpy(search_claim.addr, mac, ETH_ALEN);
 542         search_claim.vid = vid;
 543         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 544
 545         /* create a new claim entry if it does not exist yet. */
 546         if (!claim) {
 547                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 548                 if (!claim)
 549                         return;
 550
 551                 memcpy(claim->addr, mac, ETH_ALEN);
 552                 claim->vid = vid;
 553                 claim->lasttime = jiffies;
 554                 claim->backbone_gw = backbone_gw;
 555
 556                 atomic_set(&claim->refcount, 2);
 557                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 558                            "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 559                            mac, vid);
 560                 hash_added = batadv_hash_add(bat_priv->claim_hash,
 561                                              batadv_compare_claim,
 562                                              batadv_choose_claim, claim,
 563                                              &claim->hash_entry);
 564
 565                 if (unlikely(hash_added != 0)) {
 566                         /* only local changes happened. */
 567                         kfree(claim);
 568                         return;
 569                 }
 570         } else {
 571                 claim->lasttime = jiffies;
 572                 if (claim->backbone_gw == backbone_gw)
 573                         /* no need to register a new backbone */
 574                         goto claim_free_ref;
 575
 576                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 577                            "bla_add_claim(): changing ownership for %pM, vid %d\n",
 578                            mac, vid);
 579
 580                 claim->backbone_gw->crc ^=
 581                         crc16(0, claim->addr, ETH_ALEN);
 582                 batadv_backbone_gw_free_ref(claim->backbone_gw);
 583
 584         }
 585         /* set (new) backbone gw */
 586         atomic_inc(&backbone_gw->refcount);
 587         claim->backbone_gw = backbone_gw;
 588
 589         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 590         backbone_gw->lasttime = jiffies;
 591
 592 claim_free_ref:
 593         batadv_claim_free_ref(claim);
 594 }
 595
 596 /* Delete a claim from the claim hash which has the
 597  * given mac address and vid.
 598  */
 599 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
 600                                  const uint8_t *mac, const short vid)
 601 {
 602         struct batadv_claim search_claim, *claim;
 603
 604         memcpy(search_claim.addr, mac, ETH_ALEN);
 605         search_claim.vid = vid;
 606         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 607         if (!claim)
 608                 return;
 609
 610         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
 611                    mac, vid);
 612
 613         batadv_hash_remove(bat_priv->claim_hash, batadv_compare_claim,
 614                            batadv_choose_claim, claim);
 615         batadv_claim_free_ref(claim); /* reference from the hash is gone */
 616
 617         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 618
 619         /* don't need the reference from hash_find() anymore */
 620         batadv_claim_free_ref(claim);
 621 }
 622
 623 /* check for ANNOUNCE frame, return 1 if handled */
 624 static int batadv_handle_announce(struct batadv_priv *bat_priv,
 625                                   uint8_t *an_addr, uint8_t *backbone_addr,
 626                                   short vid)
 627 {
 628         struct batadv_backbone_gw *backbone_gw;
 629         uint16_t crc;
 630
 631         if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 632                 return 0;
 633
 634         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 635
 636         if (unlikely(!backbone_gw))
 637                 return 1;
 638
 639
 640         /* handle as ANNOUNCE frame */
 641         backbone_gw->lasttime = jiffies;
 642         crc = ntohs(*((__be16 *)(&an_addr[4])));
 643
 644         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 645                    "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %04x\n",
 646                    vid, backbone_gw->orig, crc);
 647
 648         if (backbone_gw->crc != crc) {
 649                 batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 650                            "handle_announce(): CRC FAILED for %pM/%d (my = %04x, sent = %04x)\n",
 651                            backbone_gw->orig, backbone_gw->vid,
 652                            backbone_gw->crc, crc);
 653
 654                 batadv_bla_send_request(backbone_gw);
 655         } else {
 656                 /* if we have sent a request and the crc was OK,
 657                  * we can allow traffic again.
 658                  */
 659                 if (atomic_read(&backbone_gw->request_sent)) {
 660                         atomic_dec(&backbone_gw->bat_priv->bla_num_requests);
 661                         atomic_set(&backbone_gw->request_sent, 0);
 662                 }
 663         }
 664
 665         batadv_backbone_gw_free_ref(backbone_gw);
 666         return 1;
 667 }
 668
 669 /* check for REQUEST frame, return 1 if handled */
 670 static int batadv_handle_request(struct batadv_priv *bat_priv,
 671                                  struct batadv_hard_iface *primary_if,
 672                                  uint8_t *backbone_addr,
 673                                  struct ethhdr *ethhdr, short vid)
 674 {
 675         /* check for REQUEST frame */
 676         if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
 677                 return 0;
 678
 679         /* sanity check, this should not happen on a normal switch,
 680          * we ignore it in this case.
 681          */
 682         if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 683                 return 1;
 684
 685         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 686                    "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 687                    vid, ethhdr->h_source);
 688
 689         batadv_bla_answer_request(bat_priv, primary_if, vid);
 690         return 1;
 691 }
 692
 693 /* check for UNCLAIM frame, return 1 if handled */
 694 static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
 695                                  struct batadv_hard_iface *primary_if,
 696                                  uint8_t *backbone_addr,
 697                                  uint8_t *claim_addr, short vid)
 698 {
 699         struct batadv_backbone_gw *backbone_gw;
 700
 701         /* unclaim in any case if it is our own */
 702         if (primary_if && batadv_compare_eth(backbone_addr,
 703                                              primary_if->net_dev->dev_addr))
 704                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 705                                       BATADV_CLAIM_TYPE_DEL);
 706
 707         backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
 708
 709         if (!backbone_gw)
 710                 return 1;
 711
 712         /* this must be an UNCLAIM frame */
 713         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 714                    "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 715                    claim_addr, vid, backbone_gw->orig);
 716
 717         batadv_bla_del_claim(bat_priv, claim_addr, vid);
 718         batadv_backbone_gw_free_ref(backbone_gw);
 719         return 1;
 720 }
 721
 722 /* check for CLAIM frame, return 1 if handled */
 723 static int batadv_handle_claim(struct batadv_priv *bat_priv,
 724                                struct batadv_hard_iface *primary_if,
 725                                uint8_t *backbone_addr, uint8_t *claim_addr,
 726                                short vid)
 727 {
 728         struct batadv_backbone_gw *backbone_gw;
 729
 730         /* register the gateway if not yet available, and add the claim. */
 731
 732         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 733
 734         if (unlikely(!backbone_gw))
 735                 return 1;
 736
 737         /* this must be a CLAIM frame */
 738         batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 739         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 740                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 741                                       BATADV_CLAIM_TYPE_ADD);
 742
 743         /* TODO: we could call something like tt_local_del() here. */
 744
 745         batadv_backbone_gw_free_ref(backbone_gw);
 746         return 1;
 747 }
 748
 749 /**
 750  * batadv_check_claim_group
 751  * @bat_priv: the bat priv with all the soft interface information
 752  * @hw_src: the Hardware source in the ARP Header
 753  * @hw_dst: the Hardware destination in the ARP Header
 754  * @ethhdr: pointer to the Ethernet header of the claim frame
 755  *
 756  * checks if it is a claim packet and if its on the same group.
 757  * This function also applies the group ID of the sender
 758  * if it is in the same mesh.
 759  *
 760  * returns:
 761  *      2  - if it is a claim packet and on the same group
 762  *      1  - if is a claim packet from another group
 763  *      0  - if it is not a claim packet
 764  */
 765 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 766                                     struct batadv_hard_iface *primary_if,
 767                                     uint8_t *hw_src, uint8_t *hw_dst,
 768                                     struct ethhdr *ethhdr)
 769 {
 770         uint8_t *backbone_addr;
 771         struct batadv_orig_node *orig_node;
 772         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 773
 774         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 775         bla_dst_own = &bat_priv->claim_dest;
 776
 777         /* check if it is a claim packet in general */
 778         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 779                    sizeof(bla_dst->magic)) != 0)
 780                 return 0;
 781
 782         /* if announcement packet, use the source,
 783          * otherwise assume it is in the hw_src
 784          */
 785         switch (bla_dst->type) {
 786         case BATADV_CLAIM_TYPE_ADD:
 787                 backbone_addr = hw_src;
 788                 break;
 789         case BATADV_CLAIM_TYPE_REQUEST:
 790         case BATADV_CLAIM_TYPE_ANNOUNCE:
 791         case BATADV_CLAIM_TYPE_DEL:
 792                 backbone_addr = ethhdr->h_source;
 793                 break;
 794         default:
 795                 return 0;
 796         }
 797
 798         /* don't accept claim frames from ourselves */
 799         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 800                 return 0;
 801
 802         /* if its already the same group, it is fine. */
 803         if (bla_dst->group == bla_dst_own->group)
 804                 return 2;
 805
 806         /* lets see if this originator is in our mesh */
 807         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 808
 809         /* dont accept claims from gateways which are not in
 810          * the same mesh or group.
 811          */
 812         if (!orig_node)
 813                 return 1;
 814
 815         /* if our mesh friends mac is bigger, use it for ourselves. */
 816         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 817                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 818                            "taking other backbones claim group: %04x\n",
 819                            ntohs(bla_dst->group));
 820                 bla_dst_own->group = bla_dst->group;
 821         }
 822
 823         batadv_orig_node_free_ref(orig_node);
 824
 825         return 2;
 826 }
 827
 828
 829 /* @bat_priv: the bat priv with all the soft interface information
 830  * @skb: the frame to be checked
 831  *
 832  * Check if this is a claim frame, and process it accordingly.
 833  *
 834  * returns 1 if it was a claim frame, otherwise return 0 to
 835  * tell the callee that it can use the frame on its own.
 836  */
 837 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 838                                     struct batadv_hard_iface *primary_if,
 839                                     struct sk_buff *skb)
 840 {
 841         struct ethhdr *ethhdr;
 842         struct vlan_ethhdr *vhdr;
 843         struct arphdr *arphdr;
 844         uint8_t *hw_src, *hw_dst;
 845         struct batadv_bla_claim_dst *bla_dst;
 846         uint16_t proto;
 847         int headlen;
 848         short vid = -1;
 849         int ret;
 850
 851         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 852
 853         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 854                 vhdr = (struct vlan_ethhdr *)ethhdr;
 855                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
 856                 proto = ntohs(vhdr->h_vlan_encapsulated_proto);
 857                 headlen = sizeof(*vhdr);
 858         } else {
 859                 proto = ntohs(ethhdr->h_proto);
 860                 headlen = ETH_HLEN;
 861         }
 862
 863         if (proto != ETH_P_ARP)
 864                 return 0; /* not a claim frame */
 865
 866         /* this must be a ARP frame. check if it is a claim. */
 867
 868         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 869                 return 0;
 870
 871         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 872         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 873         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 874
 875         /* Check whether the ARP frame carries a valid
 876          * IP information
 877          */
 878         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 879                 return 0;
 880         if (arphdr->ar_pro != htons(ETH_P_IP))
 881                 return 0;
 882         if (arphdr->ar_hln != ETH_ALEN)
 883                 return 0;
 884         if (arphdr->ar_pln != 4)
 885                 return 0;
 886
 887         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 888         hw_dst = hw_src + ETH_ALEN + 4;
 889         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 890
 891         /* check if it is a claim frame. */
 892         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 893                                        ethhdr);
 894         if (ret == 1)
 895                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 896                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 897                            ethhdr->h_source, vid, hw_src, hw_dst);
 898
 899         if (ret < 2)
 900                 return ret;
 901
 902         /* become a backbone gw ourselves on this vlan if not happened yet */
 903         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 904
 905         /* check for the different types of claim frames ... */
 906         switch (bla_dst->type) {
 907         case BATADV_CLAIM_TYPE_ADD:
 908                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 909                                         ethhdr->h_source, vid))
 910                         return 1;
 911                 break;
 912         case BATADV_CLAIM_TYPE_DEL:
 913                 if (batadv_handle_unclaim(bat_priv, primary_if,
 914                                           ethhdr->h_source, hw_src, vid))
 915                         return 1;
 916                 break;
 917
 918         case BATADV_CLAIM_TYPE_ANNOUNCE:
 919                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
 920                                            vid))
 921                         return 1;
 922                 break;
 923         case BATADV_CLAIM_TYPE_REQUEST:
 924                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
 925                                           vid))
 926                         return 1;
 927                 break;
 928         }
 929
 930         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 931                    "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",
 932                    ethhdr->h_source, vid, hw_src, hw_dst);
 933         return 1;
 934 }
 935
 936 /* Check when we last heard from other nodes, and remove them in case of
 937  * a time out, or clean all backbone gws if now is set.
 938  */
 939 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
 940 {
 941         struct batadv_backbone_gw *backbone_gw;
 942         struct hlist_node *node, *node_tmp;
 943         struct hlist_head *head;
 944         struct batadv_hashtable *hash;
 945         spinlock_t *list_lock;  /* protects write access to the hash lists */
 946         int i;
 947
 948         hash = bat_priv->backbone_hash;
 949         if (!hash)
 950                 return;
 951
 952         for (i = 0; i < hash->size; i++) {
 953                 head = &hash->table[i];
 954                 list_lock = &hash->list_locks[i];
 955
 956                 spin_lock_bh(list_lock);
 957                 hlist_for_each_entry_safe(backbone_gw, node, node_tmp,
 958                                           head, hash_entry) {
 959                         if (now)
 960                                 goto purge_now;
 961                         if (!batadv_has_timed_out(backbone_gw->lasttime,
 962                                                   BATADV_BLA_BACKBONE_TIMEOUT))
 963                                 continue;
 964
 965                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 966                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
 967                                    backbone_gw->orig);
 968
 969 purge_now:
 970                         /* don't wait for the pending request anymore */
 971                         if (atomic_read(&backbone_gw->request_sent))
 972                                 atomic_dec(&bat_priv->bla_num_requests);
 973
 974                         batadv_bla_del_backbone_claims(backbone_gw);
 975
 976                         hlist_del_rcu(node);
 977                         batadv_backbone_gw_free_ref(backbone_gw);
 978                 }
 979                 spin_unlock_bh(list_lock);
 980         }
 981 }
 982
 983 /**
 984  * batadv_bla_purge_claims
 985  * @bat_priv: the bat priv with all the soft interface information
 986  * @primary_if: the selected primary interface, may be NULL if now is set
 987  * @now: whether the whole hash shall be wiped now
 988  *
 989  * Check when we heard last time from our own claims, and remove them in case of
 990  * a time out, or clean all claims if now is set
 991  */
 992 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
 993                                     struct batadv_hard_iface *primary_if,
 994                                     int now)
 995 {
 996         struct batadv_claim *claim;
 997         struct hlist_node *node;
 998         struct hlist_head *head;
 999         struct batadv_hashtable *hash;
1000         int i;
1001
1002         hash = bat_priv->claim_hash;
1003         if (!hash)
1004                 return;
1005
1006         for (i = 0; i < hash->size; i++) {
1007                 head = &hash->table[i];
1008
1009                 rcu_read_lock();
1010                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1011                         if (now)
1012                                 goto purge_now;
1013                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1014                                                 primary_if->net_dev->dev_addr))
1015                                 continue;
1016                         if (!batadv_has_timed_out(claim->lasttime,
1017                                                   BATADV_BLA_CLAIM_TIMEOUT))
1018                                 continue;
1019
1020                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1021                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1022                                    claim->addr, claim->vid);
1023
1024 purge_now:
1025                         batadv_handle_unclaim(bat_priv, primary_if,
1026                                               claim->backbone_gw->orig,
1027                                               claim->addr, claim->vid);
1028                 }
1029                 rcu_read_unlock();
1030         }
1031 }
1032
1033 /**
1034  * batadv_bla_update_orig_address
1035  * @bat_priv: the bat priv with all the soft interface information
1036  * @primary_if: the new selected primary_if
1037  * @oldif: the old primary interface, may be NULL
1038  *
1039  * Update the backbone gateways when the own orig address changes.
1040  */
1041 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1042                                     struct batadv_hard_iface *primary_if,
1043                                     struct batadv_hard_iface *oldif)
1044 {
1045         struct batadv_backbone_gw *backbone_gw;
1046         struct hlist_node *node;
1047         struct hlist_head *head;
1048         struct batadv_hashtable *hash;
1049         int i;
1050
1051         /* reset bridge loop avoidance group id */
1052         bat_priv->claim_dest.group =
1053                 htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1054
1055         if (!oldif) {
1056                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1057                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1058                 return;
1059         }
1060
1061         hash = bat_priv->backbone_hash;
1062         if (!hash)
1063                 return;
1064
1065         for (i = 0; i < hash->size; i++) {
1066                 head = &hash->table[i];
1067
1068                 rcu_read_lock();
1069                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1070                         /* own orig still holds the old value. */
1071                         if (!batadv_compare_eth(backbone_gw->orig,
1072                                                 oldif->net_dev->dev_addr))
1073                                 continue;
1074
1075                         memcpy(backbone_gw->orig,
1076                                primary_if->net_dev->dev_addr, ETH_ALEN);
1077                         /* send an announce frame so others will ask for our
1078                          * claims and update their tables.
1079                          */
1080                         batadv_bla_send_announce(bat_priv, backbone_gw);
1081                 }
1082                 rcu_read_unlock();
1083         }
1084 }
1085
1086
1087
1088 /* (re)start the timer */
1089 static void batadv_bla_start_timer(struct batadv_priv *bat_priv)
1090 {
1091         INIT_DELAYED_WORK(&bat_priv->bla_work, batadv_bla_periodic_work);
1092         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla_work,
1093                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1094 }
1095
1096 /* periodic work to do:
1097  *  * purge structures when they are too old
1098  *  * send announcements
1099  */
1100 static void batadv_bla_periodic_work(struct work_struct *work)
1101 {
1102         struct delayed_work *delayed_work =
1103                 container_of(work, struct delayed_work, work);
1104         struct batadv_priv *bat_priv;
1105         struct hlist_node *node;
1106         struct hlist_head *head;
1107         struct batadv_backbone_gw *backbone_gw;
1108         struct batadv_hashtable *hash;
1109         struct batadv_hard_iface *primary_if;
1110         int i;
1111
1112         bat_priv = container_of(delayed_work, struct batadv_priv, bla_work);
1113         primary_if = batadv_primary_if_get_selected(bat_priv);
1114         if (!primary_if)
1115                 goto out;
1116
1117         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1118         batadv_bla_purge_backbone_gw(bat_priv, 0);
1119
1120         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1121                 goto out;
1122
1123         hash = bat_priv->backbone_hash;
1124         if (!hash)
1125                 goto out;
1126
1127         for (i = 0; i < hash->size; i++) {
1128                 head = &hash->table[i];
1129
1130                 rcu_read_lock();
1131                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1132                         if (!batadv_compare_eth(backbone_gw->orig,
1133                                                 primary_if->net_dev->dev_addr))
1134                                 continue;
1135
1136                         backbone_gw->lasttime = jiffies;
1137
1138                         batadv_bla_send_announce(bat_priv, backbone_gw);
1139                 }
1140                 rcu_read_unlock();
1141         }
1142 out:
1143         if (primary_if)
1144                 batadv_hardif_free_ref(primary_if);
1145
1146         batadv_bla_start_timer(bat_priv);
1147 }
1148
1149 /* The hash for claim and backbone hash receive the same key because they
1150  * are getting initialized by hash_new with the same key. Reinitializing
1151  * them with to different keys to allow nested locking without generating
1152  * lockdep warnings
1153  */
1154 static struct lock_class_key batadv_claim_hash_lock_class_key;
1155 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1156
1157 /* initialize all bla structures */
1158 int batadv_bla_init(struct batadv_priv *bat_priv)
1159 {
1160         int i;
1161         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1162         struct batadv_hard_iface *primary_if;
1163
1164         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1165
1166         /* setting claim destination address */
1167         memcpy(&bat_priv->claim_dest.magic, claim_dest, 3);
1168         bat_priv->claim_dest.type = 0;
1169         primary_if = batadv_primary_if_get_selected(bat_priv);
1170         if (primary_if) {
1171                 bat_priv->claim_dest.group =
1172                         htons(crc16(0, primary_if->net_dev->dev_addr,
1173                                     ETH_ALEN));
1174                 batadv_hardif_free_ref(primary_if);
1175         } else {
1176                 bat_priv->claim_dest.group = 0; /* will be set later */
1177         }
1178
1179         /* initialize the duplicate list */
1180         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1181                 bat_priv->bcast_duplist[i].entrytime =
1182                         jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1183         bat_priv->bcast_duplist_curr = 0;
1184
1185         if (bat_priv->claim_hash)
1186                 return 0;
1187
1188         bat_priv->claim_hash = batadv_hash_new(128);
1189         bat_priv->backbone_hash = batadv_hash_new(32);
1190
1191         if (!bat_priv->claim_hash || !bat_priv->backbone_hash)
1192                 return -ENOMEM;
1193
1194         batadv_hash_set_lock_class(bat_priv->claim_hash,
1195                                    &batadv_claim_hash_lock_class_key);
1196         batadv_hash_set_lock_class(bat_priv->backbone_hash,
1197                                    &batadv_backbone_hash_lock_class_key);
1198
1199         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1200
1201         batadv_bla_start_timer(bat_priv);
1202         return 0;
1203 }
1204
1205 /**
1206  * batadv_bla_check_bcast_duplist
1207  * @bat_priv: the bat priv with all the soft interface information
1208  * @bcast_packet: originator mac address
1209  * @hdr_size: maximum length of the frame
1210  *
1211  * check if it is on our broadcast list. Another gateway might
1212  * have sent the same packet because it is connected to the same backbone,
1213  * so we have to remove this duplicate.
1214  *
1215  * This is performed by checking the CRC, which will tell us
1216  * with a good chance that it is the same packet. If it is furthermore
1217  * sent by another host, drop it. We allow equal packets from
1218  * the same host however as this might be intended.
1219  */
1220 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1221                                    struct batadv_bcast_packet *bcast_packet,
1222                                    int hdr_size)
1223 {
1224         int i, length, curr;
1225         uint8_t *content;
1226         uint16_t crc;
1227         struct batadv_bcast_duplist_entry *entry;
1228
1229         length = hdr_size - sizeof(*bcast_packet);
1230         content = (uint8_t *)bcast_packet;
1231         content += sizeof(*bcast_packet);
1232
1233         /* calculate the crc ... */
1234         crc = crc16(0, content, length);
1235
1236         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1237                 curr = (bat_priv->bcast_duplist_curr + i) % BATADV_DUPLIST_SIZE;
1238                 entry = &bat_priv->bcast_duplist[curr];
1239
1240                 /* we can stop searching if the entry is too old ;
1241                  * later entries will be even older
1242                  */
1243                 if (batadv_has_timed_out(entry->entrytime,
1244                                          BATADV_DUPLIST_TIMEOUT))
1245                         break;
1246
1247                 if (entry->crc != crc)
1248                         continue;
1249
1250                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1251                         continue;
1252
1253                 /* this entry seems to match: same crc, not too old,
1254                  * and from another gw. therefore return 1 to forbid it.
1255                  */
1256                 return 1;
1257         }
1258         /* not found, add a new entry (overwrite the oldest entry) */
1259         curr = (bat_priv->bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1260         curr %= BATADV_DUPLIST_SIZE;
1261         entry = &bat_priv->bcast_duplist[curr];
1262         entry->crc = crc;
1263         entry->entrytime = jiffies;
1264         memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
1265         bat_priv->bcast_duplist_curr = curr;
1266
1267         /* allow it, its the first occurence. */
1268         return 0;
1269 }
1270
1271
1272
1273 /* @bat_priv: the bat priv with all the soft interface information
1274  * @orig: originator mac address
1275  *
1276  * check if the originator is a gateway for any VLAN ID.
1277  *
1278  * returns 1 if it is found, 0 otherwise
1279  */
1280 int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig)
1281 {
1282         struct batadv_hashtable *hash = bat_priv->backbone_hash;
1283         struct hlist_head *head;
1284         struct hlist_node *node;
1285         struct batadv_backbone_gw *backbone_gw;
1286         int i;
1287
1288         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1289                 return 0;
1290
1291         if (!hash)
1292                 return 0;
1293
1294         for (i = 0; i < hash->size; i++) {
1295                 head = &hash->table[i];
1296
1297                 rcu_read_lock();
1298                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1299                         if (batadv_compare_eth(backbone_gw->orig, orig)) {
1300                                 rcu_read_unlock();
1301                                 return 1;
1302                         }
1303                 }
1304                 rcu_read_unlock();
1305         }
1306
1307         return 0;
1308 }
1309
1310
1311 /**
1312  * batadv_bla_is_backbone_gw
1313  * @skb: the frame to be checked
1314  * @orig_node: the orig_node of the frame
1315  * @hdr_size: maximum length of the frame
1316  *
1317  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1318  * if the orig_node is also a gateway on the soft interface, otherwise it
1319  * returns 0.
1320  */
1321 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1322                               struct batadv_orig_node *orig_node, int hdr_size)
1323 {
1324         struct ethhdr *ethhdr;
1325         struct vlan_ethhdr *vhdr;
1326         struct batadv_backbone_gw *backbone_gw;
1327         short vid = -1;
1328
1329         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1330                 return 0;
1331
1332         /* first, find out the vid. */
1333         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1334                 return 0;
1335
1336         ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);
1337
1338         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
1339                 if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
1340                         return 0;
1341
1342                 vhdr = (struct vlan_ethhdr *)(((uint8_t *)skb->data) +
1343                                               hdr_size);
1344                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
1345         }
1346
1347         /* see if this originator is a backbone gw for this VLAN */
1348         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1349                                                 orig_node->orig, vid);
1350         if (!backbone_gw)
1351                 return 0;
1352
1353         batadv_backbone_gw_free_ref(backbone_gw);
1354         return 1;
1355 }
1356
1357 /* free all bla structures (for softinterface free or module unload) */
1358 void batadv_bla_free(struct batadv_priv *bat_priv)
1359 {
1360         struct batadv_hard_iface *primary_if;
1361
1362         cancel_delayed_work_sync(&bat_priv->bla_work);
1363         primary_if = batadv_primary_if_get_selected(bat_priv);
1364
1365         if (bat_priv->claim_hash) {
1366                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1367                 batadv_hash_destroy(bat_priv->claim_hash);
1368                 bat_priv->claim_hash = NULL;
1369         }
1370         if (bat_priv->backbone_hash) {
1371                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1372                 batadv_hash_destroy(bat_priv->backbone_hash);
1373                 bat_priv->backbone_hash = NULL;
1374         }
1375         if (primary_if)
1376                 batadv_hardif_free_ref(primary_if);
1377 }
1378
1379 /**
1380  * batadv_bla_rx
1381  * @bat_priv: the bat priv with all the soft interface information
1382  * @skb: the frame to be checked
1383  * @vid: the VLAN ID of the frame
1384  * @is_bcast: the packet came in a broadcast packet type.
1385  *
1386  * bla_rx avoidance checks if:
1387  *  * we have to race for a claim
1388  *  * if the frame is allowed on the LAN
1389  *
1390  * in these cases, the skb is further handled by this function and
1391  * returns 1, otherwise it returns 0 and the caller shall further
1392  * process the skb.
1393  */
1394 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid,
1395                   bool is_bcast)
1396 {
1397         struct ethhdr *ethhdr;
1398         struct batadv_claim search_claim, *claim = NULL;
1399         struct batadv_hard_iface *primary_if;
1400         int ret;
1401
1402         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1403
1404         primary_if = batadv_primary_if_get_selected(bat_priv);
1405         if (!primary_if)
1406                 goto handled;
1407
1408         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1409                 goto allow;
1410
1411
1412         if (unlikely(atomic_read(&bat_priv->bla_num_requests)))
1413                 /* don't allow broadcasts while requests are in flight */
1414                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1415                         goto handled;
1416
1417         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1418         search_claim.vid = vid;
1419         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1420
1421         if (!claim) {
1422                 /* possible optimization: race for a claim */
1423                 /* No claim exists yet, claim it for us!
1424                  */
1425                 batadv_handle_claim(bat_priv, primary_if,
1426                                     primary_if->net_dev->dev_addr,
1427                                     ethhdr->h_source, vid);
1428                 goto allow;
1429         }
1430
1431         /* if it is our own claim ... */
1432         if (batadv_compare_eth(claim->backbone_gw->orig,
1433                                primary_if->net_dev->dev_addr)) {
1434                 /* ... allow it in any case */
1435                 claim->lasttime = jiffies;
1436                 goto allow;
1437         }
1438
1439         /* if it is a broadcast ... */
1440         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1441                 /* ... drop it. the responsible gateway is in charge.
1442                  *
1443                  * We need to check is_bcast because with the gateway
1444                  * feature, broadcasts (like DHCP requests) may be sent
1445                  * using a unicast packet type.
1446                  */
1447                 goto handled;
1448         } else {
1449                 /* seems the client considers us as its best gateway.
1450                  * send a claim and update the claim table
1451                  * immediately.
1452                  */
1453                 batadv_handle_claim(bat_priv, primary_if,
1454                                     primary_if->net_dev->dev_addr,
1455                                     ethhdr->h_source, vid);
1456                 goto allow;
1457         }
1458 allow:
1459         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1460         ret = 0;
1461         goto out;
1462
1463 handled:
1464         kfree_skb(skb);
1465         ret = 1;
1466
1467 out:
1468         if (primary_if)
1469                 batadv_hardif_free_ref(primary_if);
1470         if (claim)
1471                 batadv_claim_free_ref(claim);
1472         return ret;
1473 }
1474
1475 /**
1476  * batadv_bla_tx
1477  * @bat_priv: the bat priv with all the soft interface information
1478  * @skb: the frame to be checked
1479  * @vid: the VLAN ID of the frame
1480  *
1481  * bla_tx checks if:
1482  *  * a claim was received which has to be processed
1483  *  * the frame is allowed on the mesh
1484  *
1485  * in these cases, the skb is further handled by this function and
1486  * returns 1, otherwise it returns 0 and the caller shall further
1487  * process the skb.
1488  */
1489 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid)
1490 {
1491         struct ethhdr *ethhdr;
1492         struct batadv_claim search_claim, *claim = NULL;
1493         struct batadv_hard_iface *primary_if;
1494         int ret = 0;
1495
1496         primary_if = batadv_primary_if_get_selected(bat_priv);
1497         if (!primary_if)
1498                 goto out;
1499
1500         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1501                 goto allow;
1502
1503         /* in VLAN case, the mac header might not be set. */
1504         skb_reset_mac_header(skb);
1505
1506         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1507                 goto handled;
1508
1509         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1510
1511         if (unlikely(atomic_read(&bat_priv->bla_num_requests)))
1512                 /* don't allow broadcasts while requests are in flight */
1513                 if (is_multicast_ether_addr(ethhdr->h_dest))
1514                         goto handled;
1515
1516         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1517         search_claim.vid = vid;
1518
1519         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1520
1521         /* if no claim exists, allow it. */
1522         if (!claim)
1523                 goto allow;
1524
1525         /* check if we are responsible. */
1526         if (batadv_compare_eth(claim->backbone_gw->orig,
1527                                primary_if->net_dev->dev_addr)) {
1528                 /* if yes, the client has roamed and we have
1529                  * to unclaim it.
1530                  */
1531                 batadv_handle_unclaim(bat_priv, primary_if,
1532                                       primary_if->net_dev->dev_addr,
1533                                       ethhdr->h_source, vid);
1534                 goto allow;
1535         }
1536
1537         /* check if it is a multicast/broadcast frame */
1538         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1539                 /* drop it. the responsible gateway has forwarded it into
1540                  * the backbone network.
1541                  */
1542                 goto handled;
1543         } else {
1544                 /* we must allow it. at least if we are
1545                  * responsible for the DESTINATION.
1546                  */
1547                 goto allow;
1548         }
1549 allow:
1550         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1551         ret = 0;
1552         goto out;
1553 handled:
1554         ret = 1;
1555 out:
1556         if (primary_if)
1557                 batadv_hardif_free_ref(primary_if);
1558         if (claim)
1559                 batadv_claim_free_ref(claim);
1560         return ret;
1561 }
1562
1563 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1564 {
1565         struct net_device *net_dev = (struct net_device *)seq->private;
1566         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1567         struct batadv_hashtable *hash = bat_priv->claim_hash;
1568         struct batadv_claim *claim;
1569         struct batadv_hard_iface *primary_if;
1570         struct hlist_node *node;
1571         struct hlist_head *head;
1572         uint32_t i;
1573         bool is_own;
1574         int ret = 0;
1575         uint8_t *primary_addr;
1576
1577         primary_if = batadv_primary_if_get_selected(bat_priv);
1578         if (!primary_if) {
1579                 ret = seq_printf(seq,
1580                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
1581                                  net_dev->name);
1582                 goto out;
1583         }
1584
1585         if (primary_if->if_status != BATADV_IF_ACTIVE) {
1586                 ret = seq_printf(seq,
1587                                  "BATMAN mesh %s disabled - primary interface not active\n",
1588                                  net_dev->name);
1589                 goto out;
1590         }
1591
1592         primary_addr = primary_if->net_dev->dev_addr;
1593         seq_printf(seq,
1594                    "Claims announced for the mesh %s (orig %pM, group id %04x)\n",
1595                    net_dev->name, primary_addr,
1596                    ntohs(bat_priv->claim_dest.group));
1597         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-4s)\n",
1598                    "Client", "VID", "Originator", "CRC");
1599         for (i = 0; i < hash->size; i++) {
1600                 head = &hash->table[i];
1601
1602                 rcu_read_lock();
1603                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1604                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1605                                                     primary_addr);
1606                         seq_printf(seq, " * %pM on % 5d by %pM [%c] (%04x)\n",
1607                                    claim->addr, claim->vid,
1608                                    claim->backbone_gw->orig,
1609                                    (is_own ? 'x' : ' '),
1610                                    claim->backbone_gw->crc);
1611                 }
1612                 rcu_read_unlock();
1613         }
1614 out:
1615         if (primary_if)
1616                 batadv_hardif_free_ref(primary_if);
1617         return ret;
1618 }