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->bla.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->bla.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->bla.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->bla.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:YY:YY
 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_CLAIM:
 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_UNCLAIM:
 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 and header destination to the receiving backbone
 327                  * gws mac
 328                  */
 329                 memcpy(hw_src, mac, ETH_ALEN);
 330                 memcpy(ethhdr->h_dest, mac, ETH_ALEN);
 331                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 332                            "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
 333                            ethhdr->h_source, ethhdr->h_dest, vid);
 334                 break;
 335
 336         }
 337
 338         if (vid != -1)
 339                 skb = vlan_insert_tag(skb, vid);
 340
 341         skb_reset_mac_header(skb);
 342         skb->protocol = eth_type_trans(skb, soft_iface);
 343         batadv_inc_counter(bat_priv, BATADV_CNT_RX);
 344         batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
 345                            skb->len + ETH_HLEN);
 346         soft_iface->last_rx = jiffies;
 347
 348         netif_rx(skb);
 349 out:
 350         if (primary_if)
 351                 batadv_hardif_free_ref(primary_if);
 352 }
 353
 354 /**
 355  * batadv_bla_get_backbone_gw
 356  * @bat_priv: the bat priv with all the soft interface information
 357  * @orig: the mac address of the originator
 358  * @vid: the VLAN ID
 359  *
 360  * searches for the backbone gw or creates a new one if it could not
 361  * be found.
 362  */
 363 static struct batadv_backbone_gw *
 364 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 365                            short vid)
 366 {
 367         struct batadv_backbone_gw *entry;
 368         struct batadv_orig_node *orig_node;
 369         int hash_added;
 370
 371         entry = batadv_backbone_hash_find(bat_priv, orig, vid);
 372
 373         if (entry)
 374                 return entry;
 375
 376         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 377                    "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 378                    orig, vid);
 379
 380         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 381         if (!entry)
 382                 return NULL;
 383
 384         entry->vid = vid;
 385         entry->lasttime = jiffies;
 386         entry->crc = BATADV_BLA_CRC_INIT;
 387         entry->bat_priv = bat_priv;
 388         atomic_set(&entry->request_sent, 0);
 389         memcpy(entry->orig, orig, ETH_ALEN);
 390
 391         /* one for the hash, one for returning */
 392         atomic_set(&entry->refcount, 2);
 393
 394         hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
 395                                      batadv_compare_backbone_gw,
 396                                      batadv_choose_backbone_gw, entry,
 397                                      &entry->hash_entry);
 398
 399         if (unlikely(hash_added != 0)) {
 400                 /* hash failed, free the structure */
 401                 kfree(entry);
 402                 return NULL;
 403         }
 404
 405         /* this is a gateway now, remove any tt entries */
 406         orig_node = batadv_orig_hash_find(bat_priv, orig);
 407         if (orig_node) {
 408                 batadv_tt_global_del_orig(bat_priv, orig_node,
 409                                           "became a backbone gateway");
 410                 batadv_orig_node_free_ref(orig_node);
 411         }
 412         return entry;
 413 }
 414
 415 /* update or add the own backbone gw to make sure we announce
 416  * where we receive other backbone gws
 417  */
 418 static void
 419 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 420                                   struct batadv_hard_iface *primary_if,
 421                                   short vid)
 422 {
 423         struct batadv_backbone_gw *backbone_gw;
 424
 425         backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 426                                                  primary_if->net_dev->dev_addr,
 427                                                  vid);
 428         if (unlikely(!backbone_gw))
 429                 return;
 430
 431         backbone_gw->lasttime = jiffies;
 432         batadv_backbone_gw_free_ref(backbone_gw);
 433 }
 434
 435 /* @bat_priv: the bat priv with all the soft interface information
 436  * @vid: the vid where the request came on
 437  *
 438  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 439  * to allow the requester another check if the CRC is correct now.
 440  */
 441 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
 442                                       struct batadv_hard_iface *primary_if,
 443                                       short vid)
 444 {
 445         struct hlist_node *node;
 446         struct hlist_head *head;
 447         struct batadv_hashtable *hash;
 448         struct batadv_claim *claim;
 449         struct batadv_backbone_gw *backbone_gw;
 450         int i;
 451
 452         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 453                    "bla_answer_request(): received a claim request, send all of our own claims again\n");
 454
 455         backbone_gw = batadv_backbone_hash_find(bat_priv,
 456                                                 primary_if->net_dev->dev_addr,
 457                                                 vid);
 458         if (!backbone_gw)
 459                 return;
 460
 461         hash = bat_priv->bla.claim_hash;
 462         for (i = 0; i < hash->size; i++) {
 463                 head = &hash->table[i];
 464
 465                 rcu_read_lock();
 466                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 467                         /* only own claims are interesting */
 468                         if (claim->backbone_gw != backbone_gw)
 469                                 continue;
 470
 471                         batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
 472                                               BATADV_CLAIM_TYPE_CLAIM);
 473                 }
 474                 rcu_read_unlock();
 475         }
 476
 477         /* finally, send an announcement frame */
 478         batadv_bla_send_announce(bat_priv, backbone_gw);
 479         batadv_backbone_gw_free_ref(backbone_gw);
 480 }
 481
 482 /* @backbone_gw: the backbone gateway from whom we are out of sync
 483  *
 484  * When the crc is wrong, ask the backbone gateway for a full table update.
 485  * After the request, it will repeat all of his own claims and finally
 486  * send an announcement claim with which we can check again.
 487  */
 488 static void batadv_bla_send_request(struct batadv_backbone_gw *backbone_gw)
 489 {
 490         /* first, remove all old entries */
 491         batadv_bla_del_backbone_claims(backbone_gw);
 492
 493         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 494                    "Sending REQUEST to %pM\n", backbone_gw->orig);
 495
 496         /* send request */
 497         batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 498                               backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
 499
 500         /* no local broadcasts should be sent or received, for now. */
 501         if (!atomic_read(&backbone_gw->request_sent)) {
 502                 atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
 503                 atomic_set(&backbone_gw->request_sent, 1);
 504         }
 505 }
 506
 507 /* @bat_priv: the bat priv with all the soft interface information
 508  * @backbone_gw: our backbone gateway which should be announced
 509  *
 510  * This function sends an announcement. It is called from multiple
 511  * places.
 512  */
 513 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 514                                      struct batadv_backbone_gw *backbone_gw)
 515 {
 516         uint8_t mac[ETH_ALEN];
 517         __be16 crc;
 518
 519         memcpy(mac, batadv_announce_mac, 4);
 520         crc = htons(backbone_gw->crc);
 521         memcpy(&mac[4], &crc, 2);
 522
 523         batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
 524                               BATADV_CLAIM_TYPE_ANNOUNCE);
 525
 526 }
 527
 528 /**
 529  * batadv_bla_add_claim - Adds a claim in the claim hash
 530  * @bat_priv: the bat priv with all the soft interface information
 531  * @mac: the mac address of the claim
 532  * @vid: the VLAN ID of the frame
 533  * @backbone_gw: the backbone gateway which claims it
 534  */
 535 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
 536                                  const uint8_t *mac, const short vid,
 537                                  struct batadv_backbone_gw *backbone_gw)
 538 {
 539         struct batadv_claim *claim;
 540         struct batadv_claim search_claim;
 541         int hash_added;
 542
 543         memcpy(search_claim.addr, mac, ETH_ALEN);
 544         search_claim.vid = vid;
 545         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 546
 547         /* create a new claim entry if it does not exist yet. */
 548         if (!claim) {
 549                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 550                 if (!claim)
 551                         return;
 552
 553                 memcpy(claim->addr, mac, ETH_ALEN);
 554                 claim->vid = vid;
 555                 claim->lasttime = jiffies;
 556                 claim->backbone_gw = backbone_gw;
 557
 558                 atomic_set(&claim->refcount, 2);
 559                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 560                            "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 561                            mac, vid);
 562                 hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
 563                                              batadv_compare_claim,
 564                                              batadv_choose_claim, claim,
 565                                              &claim->hash_entry);
 566
 567                 if (unlikely(hash_added != 0)) {
 568                         /* only local changes happened. */
 569                         kfree(claim);
 570                         return;
 571                 }
 572         } else {
 573                 claim->lasttime = jiffies;
 574                 if (claim->backbone_gw == backbone_gw)
 575                         /* no need to register a new backbone */
 576                         goto claim_free_ref;
 577
 578                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 579                            "bla_add_claim(): changing ownership for %pM, vid %d\n",
 580                            mac, vid);
 581
 582                 claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 583                 batadv_backbone_gw_free_ref(claim->backbone_gw);
 584
 585         }
 586         /* set (new) backbone gw */
 587         atomic_inc(&backbone_gw->refcount);
 588         claim->backbone_gw = backbone_gw;
 589
 590         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 591         backbone_gw->lasttime = jiffies;
 592
 593 claim_free_ref:
 594         batadv_claim_free_ref(claim);
 595 }
 596
 597 /* Delete a claim from the claim hash which has the
 598  * given mac address and vid.
 599  */
 600 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
 601                                  const uint8_t *mac, const short vid)
 602 {
 603         struct batadv_claim search_claim, *claim;
 604
 605         memcpy(search_claim.addr, mac, ETH_ALEN);
 606         search_claim.vid = vid;
 607         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 608         if (!claim)
 609                 return;
 610
 611         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
 612                    mac, vid);
 613
 614         batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
 615                            batadv_choose_claim, claim);
 616         batadv_claim_free_ref(claim); /* reference from the hash is gone */
 617
 618         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 619
 620         /* don't need the reference from hash_find() anymore */
 621         batadv_claim_free_ref(claim);
 622 }
 623
 624 /* check for ANNOUNCE frame, return 1 if handled */
 625 static int batadv_handle_announce(struct batadv_priv *bat_priv,
 626                                   uint8_t *an_addr, uint8_t *backbone_addr,
 627                                   short vid)
 628 {
 629         struct batadv_backbone_gw *backbone_gw;
 630         uint16_t crc;
 631
 632         if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 633                 return 0;
 634
 635         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 636
 637         if (unlikely(!backbone_gw))
 638                 return 1;
 639
 640
 641         /* handle as ANNOUNCE frame */
 642         backbone_gw->lasttime = jiffies;
 643         crc = ntohs(*((__be16 *)(&an_addr[4])));
 644
 645         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 646                    "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %04x\n",
 647                    vid, backbone_gw->orig, crc);
 648
 649         if (backbone_gw->crc != crc) {
 650                 batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 651                            "handle_announce(): CRC FAILED for %pM/%d (my = %04x, sent = %04x)\n",
 652                            backbone_gw->orig, backbone_gw->vid,
 653                            backbone_gw->crc, crc);
 654
 655                 batadv_bla_send_request(backbone_gw);
 656         } else {
 657                 /* if we have sent a request and the crc was OK,
 658                  * we can allow traffic again.
 659                  */
 660                 if (atomic_read(&backbone_gw->request_sent)) {
 661                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
 662                         atomic_set(&backbone_gw->request_sent, 0);
 663                 }
 664         }
 665
 666         batadv_backbone_gw_free_ref(backbone_gw);
 667         return 1;
 668 }
 669
 670 /* check for REQUEST frame, return 1 if handled */
 671 static int batadv_handle_request(struct batadv_priv *bat_priv,
 672                                  struct batadv_hard_iface *primary_if,
 673                                  uint8_t *backbone_addr,
 674                                  struct ethhdr *ethhdr, short vid)
 675 {
 676         /* check for REQUEST frame */
 677         if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
 678                 return 0;
 679
 680         /* sanity check, this should not happen on a normal switch,
 681          * we ignore it in this case.
 682          */
 683         if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 684                 return 1;
 685
 686         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 687                    "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 688                    vid, ethhdr->h_source);
 689
 690         batadv_bla_answer_request(bat_priv, primary_if, vid);
 691         return 1;
 692 }
 693
 694 /* check for UNCLAIM frame, return 1 if handled */
 695 static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
 696                                  struct batadv_hard_iface *primary_if,
 697                                  uint8_t *backbone_addr,
 698                                  uint8_t *claim_addr, short vid)
 699 {
 700         struct batadv_backbone_gw *backbone_gw;
 701
 702         /* unclaim in any case if it is our own */
 703         if (primary_if && batadv_compare_eth(backbone_addr,
 704                                              primary_if->net_dev->dev_addr))
 705                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 706                                       BATADV_CLAIM_TYPE_UNCLAIM);
 707
 708         backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
 709
 710         if (!backbone_gw)
 711                 return 1;
 712
 713         /* this must be an UNCLAIM frame */
 714         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 715                    "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 716                    claim_addr, vid, backbone_gw->orig);
 717
 718         batadv_bla_del_claim(bat_priv, claim_addr, vid);
 719         batadv_backbone_gw_free_ref(backbone_gw);
 720         return 1;
 721 }
 722
 723 /* check for CLAIM frame, return 1 if handled */
 724 static int batadv_handle_claim(struct batadv_priv *bat_priv,
 725                                struct batadv_hard_iface *primary_if,
 726                                uint8_t *backbone_addr, uint8_t *claim_addr,
 727                                short vid)
 728 {
 729         struct batadv_backbone_gw *backbone_gw;
 730
 731         /* register the gateway if not yet available, and add the claim. */
 732
 733         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
 734
 735         if (unlikely(!backbone_gw))
 736                 return 1;
 737
 738         /* this must be a CLAIM frame */
 739         batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 740         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 741                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 742                                       BATADV_CLAIM_TYPE_CLAIM);
 743
 744         /* TODO: we could call something like tt_local_del() here. */
 745
 746         batadv_backbone_gw_free_ref(backbone_gw);
 747         return 1;
 748 }
 749
 750 /**
 751  * batadv_check_claim_group
 752  * @bat_priv: the bat priv with all the soft interface information
 753  * @hw_src: the Hardware source in the ARP Header
 754  * @hw_dst: the Hardware destination in the ARP Header
 755  * @ethhdr: pointer to the Ethernet header of the claim frame
 756  *
 757  * checks if it is a claim packet and if its on the same group.
 758  * This function also applies the group ID of the sender
 759  * if it is in the same mesh.
 760  *
 761  * returns:
 762  *      2  - if it is a claim packet and on the same group
 763  *      1  - if is a claim packet from another group
 764  *      0  - if it is not a claim packet
 765  */
 766 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 767                                     struct batadv_hard_iface *primary_if,
 768                                     uint8_t *hw_src, uint8_t *hw_dst,
 769                                     struct ethhdr *ethhdr)
 770 {
 771         uint8_t *backbone_addr;
 772         struct batadv_orig_node *orig_node;
 773         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 774
 775         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 776         bla_dst_own = &bat_priv->bla.claim_dest;
 777
 778         /* check if it is a claim packet in general */
 779         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 780                    sizeof(bla_dst->magic)) != 0)
 781                 return 0;
 782
 783         /* if announcement packet, use the source,
 784          * otherwise assume it is in the hw_src
 785          */
 786         switch (bla_dst->type) {
 787         case BATADV_CLAIM_TYPE_CLAIM:
 788                 backbone_addr = hw_src;
 789                 break;
 790         case BATADV_CLAIM_TYPE_REQUEST:
 791         case BATADV_CLAIM_TYPE_ANNOUNCE:
 792         case BATADV_CLAIM_TYPE_UNCLAIM:
 793                 backbone_addr = ethhdr->h_source;
 794                 break;
 795         default:
 796                 return 0;
 797         }
 798
 799         /* don't accept claim frames from ourselves */
 800         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 801                 return 0;
 802
 803         /* if its already the same group, it is fine. */
 804         if (bla_dst->group == bla_dst_own->group)
 805                 return 2;
 806
 807         /* lets see if this originator is in our mesh */
 808         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 809
 810         /* dont accept claims from gateways which are not in
 811          * the same mesh or group.
 812          */
 813         if (!orig_node)
 814                 return 1;
 815
 816         /* if our mesh friends mac is bigger, use it for ourselves. */
 817         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 818                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 819                            "taking other backbones claim group: %04x\n",
 820                            ntohs(bla_dst->group));
 821                 bla_dst_own->group = bla_dst->group;
 822         }
 823
 824         batadv_orig_node_free_ref(orig_node);
 825
 826         return 2;
 827 }
 828
 829
 830 /* @bat_priv: the bat priv with all the soft interface information
 831  * @skb: the frame to be checked
 832  *
 833  * Check if this is a claim frame, and process it accordingly.
 834  *
 835  * returns 1 if it was a claim frame, otherwise return 0 to
 836  * tell the callee that it can use the frame on its own.
 837  */
 838 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 839                                     struct batadv_hard_iface *primary_if,
 840                                     struct sk_buff *skb)
 841 {
 842         struct ethhdr *ethhdr;
 843         struct vlan_ethhdr *vhdr;
 844         struct arphdr *arphdr;
 845         uint8_t *hw_src, *hw_dst;
 846         struct batadv_bla_claim_dst *bla_dst;
 847         uint16_t proto;
 848         int headlen;
 849         short vid = -1;
 850         int ret;
 851
 852         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 853
 854         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 855                 vhdr = (struct vlan_ethhdr *)ethhdr;
 856                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
 857                 proto = ntohs(vhdr->h_vlan_encapsulated_proto);
 858                 headlen = sizeof(*vhdr);
 859         } else {
 860                 proto = ntohs(ethhdr->h_proto);
 861                 headlen = ETH_HLEN;
 862         }
 863
 864         if (proto != ETH_P_ARP)
 865                 return 0; /* not a claim frame */
 866
 867         /* this must be a ARP frame. check if it is a claim. */
 868
 869         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 870                 return 0;
 871
 872         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 873         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 874         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 875
 876         /* Check whether the ARP frame carries a valid
 877          * IP information
 878          */
 879         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 880                 return 0;
 881         if (arphdr->ar_pro != htons(ETH_P_IP))
 882                 return 0;
 883         if (arphdr->ar_hln != ETH_ALEN)
 884                 return 0;
 885         if (arphdr->ar_pln != 4)
 886                 return 0;
 887
 888         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 889         hw_dst = hw_src + ETH_ALEN + 4;
 890         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 891
 892         /* check if it is a claim frame. */
 893         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 894                                        ethhdr);
 895         if (ret == 1)
 896                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 897                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 898                            ethhdr->h_source, vid, hw_src, hw_dst);
 899
 900         if (ret < 2)
 901                 return ret;
 902
 903         /* become a backbone gw ourselves on this vlan if not happened yet */
 904         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 905
 906         /* check for the different types of claim frames ... */
 907         switch (bla_dst->type) {
 908         case BATADV_CLAIM_TYPE_CLAIM:
 909                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 910                                         ethhdr->h_source, vid))
 911                         return 1;
 912                 break;
 913         case BATADV_CLAIM_TYPE_UNCLAIM:
 914                 if (batadv_handle_unclaim(bat_priv, primary_if,
 915                                           ethhdr->h_source, hw_src, vid))
 916                         return 1;
 917                 break;
 918
 919         case BATADV_CLAIM_TYPE_ANNOUNCE:
 920                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
 921                                            vid))
 922                         return 1;
 923                 break;
 924         case BATADV_CLAIM_TYPE_REQUEST:
 925                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
 926                                           vid))
 927                         return 1;
 928                 break;
 929         }
 930
 931         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 932                    "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",
 933                    ethhdr->h_source, vid, hw_src, hw_dst);
 934         return 1;
 935 }
 936
 937 /* Check when we last heard from other nodes, and remove them in case of
 938  * a time out, or clean all backbone gws if now is set.
 939  */
 940 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
 941 {
 942         struct batadv_backbone_gw *backbone_gw;
 943         struct hlist_node *node, *node_tmp;
 944         struct hlist_head *head;
 945         struct batadv_hashtable *hash;
 946         spinlock_t *list_lock;  /* protects write access to the hash lists */
 947         int i;
 948
 949         hash = bat_priv->bla.backbone_hash;
 950         if (!hash)
 951                 return;
 952
 953         for (i = 0; i < hash->size; i++) {
 954                 head = &hash->table[i];
 955                 list_lock = &hash->list_locks[i];
 956
 957                 spin_lock_bh(list_lock);
 958                 hlist_for_each_entry_safe(backbone_gw, node, node_tmp,
 959                                           head, hash_entry) {
 960                         if (now)
 961                                 goto purge_now;
 962                         if (!batadv_has_timed_out(backbone_gw->lasttime,
 963                                                   BATADV_BLA_BACKBONE_TIMEOUT))
 964                                 continue;
 965
 966                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 967                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
 968                                    backbone_gw->orig);
 969
 970 purge_now:
 971                         /* don't wait for the pending request anymore */
 972                         if (atomic_read(&backbone_gw->request_sent))
 973                                 atomic_dec(&bat_priv->bla.num_requests);
 974
 975                         batadv_bla_del_backbone_claims(backbone_gw);
 976
 977                         hlist_del_rcu(node);
 978                         batadv_backbone_gw_free_ref(backbone_gw);
 979                 }
 980                 spin_unlock_bh(list_lock);
 981         }
 982 }
 983
 984 /**
 985  * batadv_bla_purge_claims
 986  * @bat_priv: the bat priv with all the soft interface information
 987  * @primary_if: the selected primary interface, may be NULL if now is set
 988  * @now: whether the whole hash shall be wiped now
 989  *
 990  * Check when we heard last time from our own claims, and remove them in case of
 991  * a time out, or clean all claims if now is set
 992  */
 993 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
 994                                     struct batadv_hard_iface *primary_if,
 995                                     int now)
 996 {
 997         struct batadv_claim *claim;
 998         struct hlist_node *node;
 999         struct hlist_head *head;
1000         struct batadv_hashtable *hash;
1001         int i;
1002
1003         hash = bat_priv->bla.claim_hash;
1004         if (!hash)
1005                 return;
1006
1007         for (i = 0; i < hash->size; i++) {
1008                 head = &hash->table[i];
1009
1010                 rcu_read_lock();
1011                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1012                         if (now)
1013                                 goto purge_now;
1014                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1015                                                 primary_if->net_dev->dev_addr))
1016                                 continue;
1017                         if (!batadv_has_timed_out(claim->lasttime,
1018                                                   BATADV_BLA_CLAIM_TIMEOUT))
1019                                 continue;
1020
1021                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1022                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1023                                    claim->addr, claim->vid);
1024
1025 purge_now:
1026                         batadv_handle_unclaim(bat_priv, primary_if,
1027                                               claim->backbone_gw->orig,
1028                                               claim->addr, claim->vid);
1029                 }
1030                 rcu_read_unlock();
1031         }
1032 }
1033
1034 /**
1035  * batadv_bla_update_orig_address
1036  * @bat_priv: the bat priv with all the soft interface information
1037  * @primary_if: the new selected primary_if
1038  * @oldif: the old primary interface, may be NULL
1039  *
1040  * Update the backbone gateways when the own orig address changes.
1041  */
1042 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1043                                     struct batadv_hard_iface *primary_if,
1044                                     struct batadv_hard_iface *oldif)
1045 {
1046         struct batadv_backbone_gw *backbone_gw;
1047         struct hlist_node *node;
1048         struct hlist_head *head;
1049         struct batadv_hashtable *hash;
1050         __be16 group;
1051         int i;
1052
1053         /* reset bridge loop avoidance group id */
1054         group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1055         bat_priv->bla.claim_dest.group = group;
1056
1057         if (!oldif) {
1058                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1059                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1060                 return;
1061         }
1062
1063         hash = bat_priv->bla.backbone_hash;
1064         if (!hash)
1065                 return;
1066
1067         for (i = 0; i < hash->size; i++) {
1068                 head = &hash->table[i];
1069
1070                 rcu_read_lock();
1071                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1072                         /* own orig still holds the old value. */
1073                         if (!batadv_compare_eth(backbone_gw->orig,
1074                                                 oldif->net_dev->dev_addr))
1075                                 continue;
1076
1077                         memcpy(backbone_gw->orig,
1078                                primary_if->net_dev->dev_addr, ETH_ALEN);
1079                         /* send an announce frame so others will ask for our
1080                          * claims and update their tables.
1081                          */
1082                         batadv_bla_send_announce(bat_priv, backbone_gw);
1083                 }
1084                 rcu_read_unlock();
1085         }
1086 }
1087
1088
1089
1090 /* (re)start the timer */
1091 static void batadv_bla_start_timer(struct batadv_priv *bat_priv)
1092 {
1093         INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1094         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1095                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1096 }
1097
1098 /* periodic work to do:
1099  *  * purge structures when they are too old
1100  *  * send announcements
1101  */
1102 static void batadv_bla_periodic_work(struct work_struct *work)
1103 {
1104         struct delayed_work *delayed_work;
1105         struct batadv_priv *bat_priv;
1106         struct batadv_priv_bla *priv_bla;
1107         struct hlist_node *node;
1108         struct hlist_head *head;
1109         struct batadv_backbone_gw *backbone_gw;
1110         struct batadv_hashtable *hash;
1111         struct batadv_hard_iface *primary_if;
1112         int i;
1113
1114         delayed_work = container_of(work, struct delayed_work, work);
1115         priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1116         bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1117         primary_if = batadv_primary_if_get_selected(bat_priv);
1118         if (!primary_if)
1119                 goto out;
1120
1121         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1122         batadv_bla_purge_backbone_gw(bat_priv, 0);
1123
1124         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1125                 goto out;
1126
1127         hash = bat_priv->bla.backbone_hash;
1128         if (!hash)
1129                 goto out;
1130
1131         for (i = 0; i < hash->size; i++) {
1132                 head = &hash->table[i];
1133
1134                 rcu_read_lock();
1135                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1136                         if (!batadv_compare_eth(backbone_gw->orig,
1137                                                 primary_if->net_dev->dev_addr))
1138                                 continue;
1139
1140                         backbone_gw->lasttime = jiffies;
1141
1142                         batadv_bla_send_announce(bat_priv, backbone_gw);
1143                 }
1144                 rcu_read_unlock();
1145         }
1146 out:
1147         if (primary_if)
1148                 batadv_hardif_free_ref(primary_if);
1149
1150         batadv_bla_start_timer(bat_priv);
1151 }
1152
1153 /* The hash for claim and backbone hash receive the same key because they
1154  * are getting initialized by hash_new with the same key. Reinitializing
1155  * them with to different keys to allow nested locking without generating
1156  * lockdep warnings
1157  */
1158 static struct lock_class_key batadv_claim_hash_lock_class_key;
1159 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1160
1161 /* initialize all bla structures */
1162 int batadv_bla_init(struct batadv_priv *bat_priv)
1163 {
1164         int i;
1165         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1166         struct batadv_hard_iface *primary_if;
1167         uint16_t crc;
1168         unsigned long entrytime;
1169
1170         spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1171
1172         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1173
1174         /* setting claim destination address */
1175         memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1176         bat_priv->bla.claim_dest.type = 0;
1177         primary_if = batadv_primary_if_get_selected(bat_priv);
1178         if (primary_if) {
1179                 crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1180                 bat_priv->bla.claim_dest.group = htons(crc);
1181                 batadv_hardif_free_ref(primary_if);
1182         } else {
1183                 bat_priv->bla.claim_dest.group = 0; /* will be set later */
1184         }
1185
1186         /* initialize the duplicate list */
1187         entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1188         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1189                 bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1190         bat_priv->bla.bcast_duplist_curr = 0;
1191
1192         if (bat_priv->bla.claim_hash)
1193                 return 0;
1194
1195         bat_priv->bla.claim_hash = batadv_hash_new(128);
1196         bat_priv->bla.backbone_hash = batadv_hash_new(32);
1197
1198         if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
1199                 return -ENOMEM;
1200
1201         batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1202                                    &batadv_claim_hash_lock_class_key);
1203         batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1204                                    &batadv_backbone_hash_lock_class_key);
1205
1206         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1207
1208         batadv_bla_start_timer(bat_priv);
1209         return 0;
1210 }
1211
1212 /**
1213  * batadv_bla_check_bcast_duplist
1214  * @bat_priv: the bat priv with all the soft interface information
1215  * @bcast_packet: encapsulated broadcast frame plus batman header
1216  * @bcast_packet_len: length of encapsulated broadcast frame plus batman header
1217  *
1218  * check if it is on our broadcast list. Another gateway might
1219  * have sent the same packet because it is connected to the same backbone,
1220  * so we have to remove this duplicate.
1221  *
1222  * This is performed by checking the CRC, which will tell us
1223  * with a good chance that it is the same packet. If it is furthermore
1224  * sent by another host, drop it. We allow equal packets from
1225  * the same host however as this might be intended.
1226  */
1227 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1228                                    struct batadv_bcast_packet *bcast_packet,
1229                                    int bcast_packet_len)
1230 {
1231         int i, length, curr, ret = 0;
1232         uint8_t *content;
1233         uint16_t crc;
1234         struct batadv_bcast_duplist_entry *entry;
1235
1236         length = bcast_packet_len - sizeof(*bcast_packet);
1237         content = (uint8_t *)bcast_packet;
1238         content += sizeof(*bcast_packet);
1239
1240         /* calculate the crc ... */
1241         crc = crc16(0, content, length);
1242
1243         spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1244
1245         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1246                 curr = (bat_priv->bla.bcast_duplist_curr + i);
1247                 curr %= BATADV_DUPLIST_SIZE;
1248                 entry = &bat_priv->bla.bcast_duplist[curr];
1249
1250                 /* we can stop searching if the entry is too old ;
1251                  * later entries will be even older
1252                  */
1253                 if (batadv_has_timed_out(entry->entrytime,
1254                                          BATADV_DUPLIST_TIMEOUT))
1255                         break;
1256
1257                 if (entry->crc != crc)
1258                         continue;
1259
1260                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1261                         continue;
1262
1263                 /* this entry seems to match: same crc, not too old,
1264                  * and from another gw. therefore return 1 to forbid it.
1265                  */
1266                 ret = 1;
1267                 goto out;
1268         }
1269         /* not found, add a new entry (overwrite the oldest entry)
1270          * and allow it, its the first occurence.
1271          */
1272         curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1273         curr %= BATADV_DUPLIST_SIZE;
1274         entry = &bat_priv->bla.bcast_duplist[curr];
1275         entry->crc = crc;
1276         entry->entrytime = jiffies;
1277         memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
1278         bat_priv->bla.bcast_duplist_curr = curr;
1279
1280 out:
1281         spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1282
1283         return ret;
1284 }
1285
1286
1287
1288 /* @bat_priv: the bat priv with all the soft interface information
1289  * @orig: originator mac address
1290  *
1291  * check if the originator is a gateway for any VLAN ID.
1292  *
1293  * returns 1 if it is found, 0 otherwise
1294  */
1295 int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig)
1296 {
1297         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1298         struct hlist_head *head;
1299         struct hlist_node *node;
1300         struct batadv_backbone_gw *backbone_gw;
1301         int i;
1302
1303         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1304                 return 0;
1305
1306         if (!hash)
1307                 return 0;
1308
1309         for (i = 0; i < hash->size; i++) {
1310                 head = &hash->table[i];
1311
1312                 rcu_read_lock();
1313                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1314                         if (batadv_compare_eth(backbone_gw->orig, orig)) {
1315                                 rcu_read_unlock();
1316                                 return 1;
1317                         }
1318                 }
1319                 rcu_read_unlock();
1320         }
1321
1322         return 0;
1323 }
1324
1325
1326 /**
1327  * batadv_bla_is_backbone_gw
1328  * @skb: the frame to be checked
1329  * @orig_node: the orig_node of the frame
1330  * @hdr_size: maximum length of the frame
1331  *
1332  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1333  * if the orig_node is also a gateway on the soft interface, otherwise it
1334  * returns 0.
1335  */
1336 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1337                               struct batadv_orig_node *orig_node, int hdr_size)
1338 {
1339         struct ethhdr *ethhdr;
1340         struct vlan_ethhdr *vhdr;
1341         struct batadv_backbone_gw *backbone_gw;
1342         short vid = -1;
1343
1344         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1345                 return 0;
1346
1347         /* first, find out the vid. */
1348         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1349                 return 0;
1350
1351         ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);
1352
1353         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
1354                 if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
1355                         return 0;
1356
1357                 vhdr = (struct vlan_ethhdr *)(skb->data + hdr_size);
1358                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
1359         }
1360
1361         /* see if this originator is a backbone gw for this VLAN */
1362         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1363                                                 orig_node->orig, vid);
1364         if (!backbone_gw)
1365                 return 0;
1366
1367         batadv_backbone_gw_free_ref(backbone_gw);
1368         return 1;
1369 }
1370
1371 /* free all bla structures (for softinterface free or module unload) */
1372 void batadv_bla_free(struct batadv_priv *bat_priv)
1373 {
1374         struct batadv_hard_iface *primary_if;
1375
1376         cancel_delayed_work_sync(&bat_priv->bla.work);
1377         primary_if = batadv_primary_if_get_selected(bat_priv);
1378
1379         if (bat_priv->bla.claim_hash) {
1380                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1381                 batadv_hash_destroy(bat_priv->bla.claim_hash);
1382                 bat_priv->bla.claim_hash = NULL;
1383         }
1384         if (bat_priv->bla.backbone_hash) {
1385                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1386                 batadv_hash_destroy(bat_priv->bla.backbone_hash);
1387                 bat_priv->bla.backbone_hash = NULL;
1388         }
1389         if (primary_if)
1390                 batadv_hardif_free_ref(primary_if);
1391 }
1392
1393 /**
1394  * batadv_bla_rx
1395  * @bat_priv: the bat priv with all the soft interface information
1396  * @skb: the frame to be checked
1397  * @vid: the VLAN ID of the frame
1398  * @is_bcast: the packet came in a broadcast packet type.
1399  *
1400  * bla_rx avoidance checks if:
1401  *  * we have to race for a claim
1402  *  * if the frame is allowed on the LAN
1403  *
1404  * in these cases, the skb is further handled by this function and
1405  * returns 1, otherwise it returns 0 and the caller shall further
1406  * process the skb.
1407  */
1408 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid,
1409                   bool is_bcast)
1410 {
1411         struct ethhdr *ethhdr;
1412         struct batadv_claim search_claim, *claim = NULL;
1413         struct batadv_hard_iface *primary_if;
1414         int ret;
1415
1416         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1417
1418         primary_if = batadv_primary_if_get_selected(bat_priv);
1419         if (!primary_if)
1420                 goto handled;
1421
1422         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1423                 goto allow;
1424
1425
1426         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1427                 /* don't allow broadcasts while requests are in flight */
1428                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1429                         goto handled;
1430
1431         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1432         search_claim.vid = vid;
1433         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1434
1435         if (!claim) {
1436                 /* possible optimization: race for a claim */
1437                 /* No claim exists yet, claim it for us!
1438                  */
1439                 batadv_handle_claim(bat_priv, primary_if,
1440                                     primary_if->net_dev->dev_addr,
1441                                     ethhdr->h_source, vid);
1442                 goto allow;
1443         }
1444
1445         /* if it is our own claim ... */
1446         if (batadv_compare_eth(claim->backbone_gw->orig,
1447                                primary_if->net_dev->dev_addr)) {
1448                 /* ... allow it in any case */
1449                 claim->lasttime = jiffies;
1450                 goto allow;
1451         }
1452
1453         /* if it is a broadcast ... */
1454         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1455                 /* ... drop it. the responsible gateway is in charge.
1456                  *
1457                  * We need to check is_bcast because with the gateway
1458                  * feature, broadcasts (like DHCP requests) may be sent
1459                  * using a unicast packet type.
1460                  */
1461                 goto handled;
1462         } else {
1463                 /* seems the client considers us as its best gateway.
1464                  * send a claim and update the claim table
1465                  * immediately.
1466                  */
1467                 batadv_handle_claim(bat_priv, primary_if,
1468                                     primary_if->net_dev->dev_addr,
1469                                     ethhdr->h_source, vid);
1470                 goto allow;
1471         }
1472 allow:
1473         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1474         ret = 0;
1475         goto out;
1476
1477 handled:
1478         kfree_skb(skb);
1479         ret = 1;
1480
1481 out:
1482         if (primary_if)
1483                 batadv_hardif_free_ref(primary_if);
1484         if (claim)
1485                 batadv_claim_free_ref(claim);
1486         return ret;
1487 }
1488
1489 /**
1490  * batadv_bla_tx
1491  * @bat_priv: the bat priv with all the soft interface information
1492  * @skb: the frame to be checked
1493  * @vid: the VLAN ID of the frame
1494  *
1495  * bla_tx checks if:
1496  *  * a claim was received which has to be processed
1497  *  * the frame is allowed on the mesh
1498  *
1499  * in these cases, the skb is further handled by this function and
1500  * returns 1, otherwise it returns 0 and the caller shall further
1501  * process the skb.
1502  */
1503 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid)
1504 {
1505         struct ethhdr *ethhdr;
1506         struct batadv_claim search_claim, *claim = NULL;
1507         struct batadv_hard_iface *primary_if;
1508         int ret = 0;
1509
1510         primary_if = batadv_primary_if_get_selected(bat_priv);
1511         if (!primary_if)
1512                 goto out;
1513
1514         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1515                 goto allow;
1516
1517         /* in VLAN case, the mac header might not be set. */
1518         skb_reset_mac_header(skb);
1519
1520         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1521                 goto handled;
1522
1523         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1524
1525         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1526                 /* don't allow broadcasts while requests are in flight */
1527                 if (is_multicast_ether_addr(ethhdr->h_dest))
1528                         goto handled;
1529
1530         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1531         search_claim.vid = vid;
1532
1533         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1534
1535         /* if no claim exists, allow it. */
1536         if (!claim)
1537                 goto allow;
1538
1539         /* check if we are responsible. */
1540         if (batadv_compare_eth(claim->backbone_gw->orig,
1541                                primary_if->net_dev->dev_addr)) {
1542                 /* if yes, the client has roamed and we have
1543                  * to unclaim it.
1544                  */
1545                 batadv_handle_unclaim(bat_priv, primary_if,
1546                                       primary_if->net_dev->dev_addr,
1547                                       ethhdr->h_source, vid);
1548                 goto allow;
1549         }
1550
1551         /* check if it is a multicast/broadcast frame */
1552         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1553                 /* drop it. the responsible gateway has forwarded it into
1554                  * the backbone network.
1555                  */
1556                 goto handled;
1557         } else {
1558                 /* we must allow it. at least if we are
1559                  * responsible for the DESTINATION.
1560                  */
1561                 goto allow;
1562         }
1563 allow:
1564         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1565         ret = 0;
1566         goto out;
1567 handled:
1568         ret = 1;
1569 out:
1570         if (primary_if)
1571                 batadv_hardif_free_ref(primary_if);
1572         if (claim)
1573                 batadv_claim_free_ref(claim);
1574         return ret;
1575 }
1576
1577 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1578 {
1579         struct net_device *net_dev = (struct net_device *)seq->private;
1580         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1581         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
1582         struct batadv_claim *claim;
1583         struct batadv_hard_iface *primary_if;
1584         struct hlist_node *node;
1585         struct hlist_head *head;
1586         uint32_t i;
1587         bool is_own;
1588         int ret = 0;
1589         uint8_t *primary_addr;
1590
1591         primary_if = batadv_primary_if_get_selected(bat_priv);
1592         if (!primary_if) {
1593                 ret = seq_printf(seq,
1594                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
1595                                  net_dev->name);
1596                 goto out;
1597         }
1598
1599         if (primary_if->if_status != BATADV_IF_ACTIVE) {
1600                 ret = seq_printf(seq,
1601                                  "BATMAN mesh %s disabled - primary interface not active\n",
1602                                  net_dev->name);
1603                 goto out;
1604         }
1605
1606         primary_addr = primary_if->net_dev->dev_addr;
1607         seq_printf(seq,
1608                    "Claims announced for the mesh %s (orig %pM, group id %04x)\n",
1609                    net_dev->name, primary_addr,
1610                    ntohs(bat_priv->bla.claim_dest.group));
1611         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-4s)\n",
1612                    "Client", "VID", "Originator", "CRC");
1613         for (i = 0; i < hash->size; i++) {
1614                 head = &hash->table[i];
1615
1616                 rcu_read_lock();
1617                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1618                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1619                                                     primary_addr);
1620                         seq_printf(seq, " * %pM on % 5d by %pM [%c] (%04x)\n",
1621                                    claim->addr, claim->vid,
1622                                    claim->backbone_gw->orig,
1623                                    (is_own ? 'x' : ' '),
1624                                    claim->backbone_gw->crc);
1625                 }
1626                 rcu_read_unlock();
1627         }
1628 out:
1629         if (primary_if)
1630                 batadv_hardif_free_ref(primary_if);
1631         return ret;
1632 }
1633
1634 int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
1635 {
1636         struct net_device *net_dev = (struct net_device *)seq->private;
1637         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1638         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1639         struct batadv_backbone_gw *backbone_gw;
1640         struct batadv_hard_iface *primary_if;
1641         struct hlist_node *node;
1642         struct hlist_head *head;
1643         int secs, msecs;
1644         uint32_t i;
1645         bool is_own;
1646         int ret = 0;
1647         uint8_t *primary_addr;
1648
1649         primary_if = batadv_primary_if_get_selected(bat_priv);
1650         if (!primary_if) {
1651                 ret = seq_printf(seq,
1652                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
1653                                  net_dev->name);
1654                 goto out;
1655         }
1656
1657         if (primary_if->if_status != BATADV_IF_ACTIVE) {
1658                 ret = seq_printf(seq,
1659                                  "BATMAN mesh %s disabled - primary interface not active\n",
1660                                  net_dev->name);
1661                 goto out;
1662         }
1663
1664         primary_addr = primary_if->net_dev->dev_addr;
1665         seq_printf(seq,
1666                    "Backbones announced for the mesh %s (orig %pM, group id %04x)\n",
1667                    net_dev->name, primary_addr,
1668                    ntohs(bat_priv->bla.claim_dest.group));
1669         seq_printf(seq, "   %-17s    %-5s %-9s (%-4s)\n",
1670                    "Originator", "VID", "last seen", "CRC");
1671         for (i = 0; i < hash->size; i++) {
1672                 head = &hash->table[i];
1673
1674                 rcu_read_lock();
1675                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1676                         msecs = jiffies_to_msecs(jiffies -
1677                                                  backbone_gw->lasttime);
1678                         secs = msecs / 1000;
1679                         msecs = msecs % 1000;
1680
1681                         is_own = batadv_compare_eth(backbone_gw->orig,
1682                                                     primary_addr);
1683                         if (is_own)
1684                                 continue;
1685
1686                         seq_printf(seq,
1687                                    " * %pM on % 5d % 4i.%03is (%04x)\n",
1688                                    backbone_gw->orig, backbone_gw->vid,
1689                                    secs, msecs, backbone_gw->crc);
1690                 }
1691                 rcu_read_unlock();
1692         }
1693 out:
1694         if (primary_if)
1695                 batadv_hardif_free_ref(primary_if);
1696         return ret;
1697 }