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