net/batman-adv/bridge_loop_avoidance.c

   1 /* Copyright (C) 2011-2014 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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "main.h"
  19 #include "hash.h"
  20 #include "hard-interface.h"
  21 #include "originator.h"
  22 #include "bridge_loop_avoidance.h"
  23 #include "translation-table.h"
  24 #include "send.h"
  25
  26 #include <linux/etherdevice.h>
  27 #include <linux/crc16.h>
  28 #include <linux/if_arp.h>
  29 #include <net/arp.h>
  30 #include <linux/if_vlan.h>
  31
  32 static const uint8_t batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
  33
  34 static void batadv_bla_periodic_work(struct work_struct *work);
  35 static void
  36 batadv_bla_send_announce(struct batadv_priv *bat_priv,
  37                          struct batadv_bla_backbone_gw *backbone_gw);
  38
  39 /* return the index of the claim */
  40 static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
  41 {
  42         struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  43         uint32_t hash = 0;
  44
  45         hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  46         hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
  47
  48         hash += (hash << 3);
  49         hash ^= (hash >> 11);
  50         hash += (hash << 15);
  51
  52         return hash % size;
  53 }
  54
  55 /* return the index of the backbone gateway */
  56 static inline uint32_t batadv_choose_backbone_gw(const void *data,
  57                                                  uint32_t size)
  58 {
  59         const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  60         uint32_t hash = 0;
  61
  62         hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  63         hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
  64
  65         hash += (hash << 3);
  66         hash ^= (hash >> 11);
  67         hash += (hash << 15);
  68
  69         return hash % size;
  70 }
  71
  72
  73 /* compares address and vid of two backbone gws */
  74 static int batadv_compare_backbone_gw(const struct hlist_node *node,
  75                                       const void *data2)
  76 {
  77         const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
  78                                          hash_entry);
  79         const struct batadv_bla_backbone_gw *gw1 = data1, *gw2 = data2;
  80
  81         if (!batadv_compare_eth(gw1->orig, gw2->orig))
  82                 return 0;
  83
  84         if (gw1->vid != gw2->vid)
  85                 return 0;
  86
  87         return 1;
  88 }
  89
  90 /* compares address and vid of two claims */
  91 static int batadv_compare_claim(const struct hlist_node *node,
  92                                 const void *data2)
  93 {
  94         const void *data1 = container_of(node, struct batadv_bla_claim,
  95                                          hash_entry);
  96         const struct batadv_bla_claim *cl1 = data1, *cl2 = data2;
  97
  98         if (!batadv_compare_eth(cl1->addr, cl2->addr))
  99                 return 0;
 100
 101         if (cl1->vid != cl2->vid)
 102                 return 0;
 103
 104         return 1;
 105 }
 106
 107 /* free a backbone gw */
 108 static void
 109 batadv_backbone_gw_free_ref(struct batadv_bla_backbone_gw *backbone_gw)
 110 {
 111         if (atomic_dec_and_test(&backbone_gw->refcount))
 112                 kfree_rcu(backbone_gw, rcu);
 113 }
 114
 115 /* finally deinitialize the claim */
 116 static void batadv_claim_free_rcu(struct rcu_head *rcu)
 117 {
 118         struct batadv_bla_claim *claim;
 119
 120         claim = container_of(rcu, struct batadv_bla_claim, rcu);
 121
 122         batadv_backbone_gw_free_ref(claim->backbone_gw);
 123         kfree(claim);
 124 }
 125
 126 /* free a claim, call claim_free_rcu if its the last reference */
 127 static void batadv_claim_free_ref(struct batadv_bla_claim *claim)
 128 {
 129         if (atomic_dec_and_test(&claim->refcount))
 130                 call_rcu(&claim->rcu, batadv_claim_free_rcu);
 131 }
 132
 133 /**
 134  * batadv_claim_hash_find
 135  * @bat_priv: the bat priv with all the soft interface information
 136  * @data: search data (may be local/static data)
 137  *
 138  * looks for a claim in the hash, and returns it if found
 139  * or NULL otherwise.
 140  */
 141 static struct batadv_bla_claim
 142 *batadv_claim_hash_find(struct batadv_priv *bat_priv,
 143                         struct batadv_bla_claim *data)
 144 {
 145         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
 146         struct hlist_head *head;
 147         struct batadv_bla_claim *claim;
 148         struct batadv_bla_claim *claim_tmp = NULL;
 149         int index;
 150
 151         if (!hash)
 152                 return NULL;
 153
 154         index = batadv_choose_claim(data, hash->size);
 155         head = &hash->table[index];
 156
 157         rcu_read_lock();
 158         hlist_for_each_entry_rcu(claim, head, hash_entry) {
 159                 if (!batadv_compare_claim(&claim->hash_entry, data))
 160                         continue;
 161
 162                 if (!atomic_inc_not_zero(&claim->refcount))
 163                         continue;
 164
 165                 claim_tmp = claim;
 166                 break;
 167         }
 168         rcu_read_unlock();
 169
 170         return claim_tmp;
 171 }
 172
 173 /**
 174  * batadv_backbone_hash_find - looks for a claim in the hash
 175  * @bat_priv: the bat priv with all the soft interface information
 176  * @addr: the address of the originator
 177  * @vid: the VLAN ID
 178  *
 179  * Returns claim if found or NULL otherwise.
 180  */
 181 static struct batadv_bla_backbone_gw *
 182 batadv_backbone_hash_find(struct batadv_priv *bat_priv,
 183                           uint8_t *addr, unsigned short vid)
 184 {
 185         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
 186         struct hlist_head *head;
 187         struct batadv_bla_backbone_gw search_entry, *backbone_gw;
 188         struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
 189         int index;
 190
 191         if (!hash)
 192                 return NULL;
 193
 194         ether_addr_copy(search_entry.orig, addr);
 195         search_entry.vid = vid;
 196
 197         index = batadv_choose_backbone_gw(&search_entry, hash->size);
 198         head = &hash->table[index];
 199
 200         rcu_read_lock();
 201         hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
 202                 if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
 203                                                 &search_entry))
 204                         continue;
 205
 206                 if (!atomic_inc_not_zero(&backbone_gw->refcount))
 207                         continue;
 208
 209                 backbone_gw_tmp = backbone_gw;
 210                 break;
 211         }
 212         rcu_read_unlock();
 213
 214         return backbone_gw_tmp;
 215 }
 216
 217 /* delete all claims for a backbone */
 218 static void
 219 batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
 220 {
 221         struct batadv_hashtable *hash;
 222         struct hlist_node *node_tmp;
 223         struct hlist_head *head;
 224         struct batadv_bla_claim *claim;
 225         int i;
 226         spinlock_t *list_lock;  /* protects write access to the hash lists */
 227
 228         hash = backbone_gw->bat_priv->bla.claim_hash;
 229         if (!hash)
 230                 return;
 231
 232         for (i = 0; i < hash->size; i++) {
 233                 head = &hash->table[i];
 234                 list_lock = &hash->list_locks[i];
 235
 236                 spin_lock_bh(list_lock);
 237                 hlist_for_each_entry_safe(claim, node_tmp,
 238                                           head, hash_entry) {
 239                         if (claim->backbone_gw != backbone_gw)
 240                                 continue;
 241
 242                         batadv_claim_free_ref(claim);
 243                         hlist_del_rcu(&claim->hash_entry);
 244                 }
 245                 spin_unlock_bh(list_lock);
 246         }
 247
 248         /* all claims gone, intialize CRC */
 249         backbone_gw->crc = BATADV_BLA_CRC_INIT;
 250 }
 251
 252 /**
 253  * batadv_bla_send_claim - sends a claim frame according to the provided info
 254  * @bat_priv: the bat priv with all the soft interface information
 255  * @orig: the mac address to be announced within the claim
 256  * @vid: the VLAN ID
 257  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 258  */
 259 static void batadv_bla_send_claim(struct batadv_priv *bat_priv, uint8_t *mac,
 260                                   unsigned short vid, int claimtype)
 261 {
 262         struct sk_buff *skb;
 263         struct ethhdr *ethhdr;
 264         struct batadv_hard_iface *primary_if;
 265         struct net_device *soft_iface;
 266         uint8_t *hw_src;
 267         struct batadv_bla_claim_dst local_claim_dest;
 268         __be32 zeroip = 0;
 269
 270         primary_if = batadv_primary_if_get_selected(bat_priv);
 271         if (!primary_if)
 272                 return;
 273
 274         memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
 275                sizeof(local_claim_dest));
 276         local_claim_dest.type = claimtype;
 277
 278         soft_iface = primary_if->soft_iface;
 279
 280         skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
 281                          /* IP DST: 0.0.0.0 */
 282                          zeroip,
 283                          primary_if->soft_iface,
 284                          /* IP SRC: 0.0.0.0 */
 285                          zeroip,
 286                          /* Ethernet DST: Broadcast */
 287                          NULL,
 288                          /* Ethernet SRC/HW SRC:  originator mac */
 289                          primary_if->net_dev->dev_addr,
 290                          /* HW DST: FF:43:05:XX:YY:YY
 291                           * with XX   = claim type
 292                           * and YY:YY = group id
 293                           */
 294                          (uint8_t *)&local_claim_dest);
 295
 296         if (!skb)
 297                 goto out;
 298
 299         ethhdr = (struct ethhdr *)skb->data;
 300         hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
 301
 302         /* now we pretend that the client would have sent this ... */
 303         switch (claimtype) {
 304         case BATADV_CLAIM_TYPE_CLAIM:
 305                 /* normal claim frame
 306                  * set Ethernet SRC to the clients mac
 307                  */
 308                 ether_addr_copy(ethhdr->h_source, mac);
 309                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 310                            "bla_send_claim(): CLAIM %pM on vid %d\n", mac,
 311                            BATADV_PRINT_VID(vid));
 312                 break;
 313         case BATADV_CLAIM_TYPE_UNCLAIM:
 314                 /* unclaim frame
 315                  * set HW SRC to the clients mac
 316                  */
 317                 ether_addr_copy(hw_src, mac);
 318                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 319                            "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
 320                            BATADV_PRINT_VID(vid));
 321                 break;
 322         case BATADV_CLAIM_TYPE_ANNOUNCE:
 323                 /* announcement frame
 324                  * set HW SRC to the special mac containg the crc
 325                  */
 326                 ether_addr_copy(hw_src, mac);
 327                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 328                            "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
 329                            ethhdr->h_source, BATADV_PRINT_VID(vid));
 330                 break;
 331         case BATADV_CLAIM_TYPE_REQUEST:
 332                 /* request frame
 333                  * set HW SRC and header destination to the receiving backbone
 334                  * gws mac
 335                  */
 336                 ether_addr_copy(hw_src, mac);
 337                 ether_addr_copy(ethhdr->h_dest, mac);
 338                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 339                            "bla_send_claim(): REQUEST of %pM to %pM on vid %d\n",
 340                            ethhdr->h_source, ethhdr->h_dest,
 341                            BATADV_PRINT_VID(vid));
 342                 break;
 343         }
 344
 345         if (vid & BATADV_VLAN_HAS_TAG)
 346                 skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
 347                                       vid & VLAN_VID_MASK);
 348
 349         skb_reset_mac_header(skb);
 350         skb->protocol = eth_type_trans(skb, soft_iface);
 351         batadv_inc_counter(bat_priv, BATADV_CNT_RX);
 352         batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
 353                            skb->len + ETH_HLEN);
 354         soft_iface->last_rx = jiffies;
 355
 356         netif_rx(skb);
 357 out:
 358         if (primary_if)
 359                 batadv_hardif_free_ref(primary_if);
 360 }
 361
 362 /**
 363  * batadv_bla_get_backbone_gw
 364  * @bat_priv: the bat priv with all the soft interface information
 365  * @orig: the mac address of the originator
 366  * @vid: the VLAN ID
 367  *
 368  * searches for the backbone gw or creates a new one if it could not
 369  * be found.
 370  */
 371 static struct batadv_bla_backbone_gw *
 372 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 373                            unsigned short vid, bool own_backbone)
 374 {
 375         struct batadv_bla_backbone_gw *entry;
 376         struct batadv_orig_node *orig_node;
 377         int hash_added;
 378
 379         entry = batadv_backbone_hash_find(bat_priv, orig, vid);
 380
 381         if (entry)
 382                 return entry;
 383
 384         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 385                    "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 386                    orig, BATADV_PRINT_VID(vid));
 387
 388         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 389         if (!entry)
 390                 return NULL;
 391
 392         entry->vid = vid;
 393         entry->lasttime = jiffies;
 394         entry->crc = BATADV_BLA_CRC_INIT;
 395         entry->bat_priv = bat_priv;
 396         atomic_set(&entry->request_sent, 0);
 397         atomic_set(&entry->wait_periods, 0);
 398         ether_addr_copy(entry->orig, orig);
 399
 400         /* one for the hash, one for returning */
 401         atomic_set(&entry->refcount, 2);
 402
 403         hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
 404                                      batadv_compare_backbone_gw,
 405                                      batadv_choose_backbone_gw, entry,
 406                                      &entry->hash_entry);
 407
 408         if (unlikely(hash_added != 0)) {
 409                 /* hash failed, free the structure */
 410                 kfree(entry);
 411                 return NULL;
 412         }
 413
 414         /* this is a gateway now, remove any TT entry on this VLAN */
 415         orig_node = batadv_orig_hash_find(bat_priv, orig);
 416         if (orig_node) {
 417                 batadv_tt_global_del_orig(bat_priv, orig_node, vid,
 418                                           "became a backbone gateway");
 419                 batadv_orig_node_free_ref(orig_node);
 420         }
 421
 422         if (own_backbone) {
 423                 batadv_bla_send_announce(bat_priv, entry);
 424
 425                 /* this will be decreased in the worker thread */
 426                 atomic_inc(&entry->request_sent);
 427                 atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
 428                 atomic_inc(&bat_priv->bla.num_requests);
 429         }
 430
 431         return entry;
 432 }
 433
 434 /* update or add the own backbone gw to make sure we announce
 435  * where we receive other backbone gws
 436  */
 437 static void
 438 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 439                                   struct batadv_hard_iface *primary_if,
 440                                   unsigned short vid)
 441 {
 442         struct batadv_bla_backbone_gw *backbone_gw;
 443
 444         backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 445                                                  primary_if->net_dev->dev_addr,
 446                                                  vid, true);
 447         if (unlikely(!backbone_gw))
 448                 return;
 449
 450         backbone_gw->lasttime = jiffies;
 451         batadv_backbone_gw_free_ref(backbone_gw);
 452 }
 453
 454 /**
 455  * batadv_bla_answer_request - answer a bla request by sending own claims
 456  * @bat_priv: the bat priv with all the soft interface information
 457  * @vid: the vid where the request came on
 458  *
 459  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 460  * to allow the requester another check if the CRC is correct now.
 461  */
 462 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
 463                                       struct batadv_hard_iface *primary_if,
 464                                       unsigned short vid)
 465 {
 466         struct hlist_head *head;
 467         struct batadv_hashtable *hash;
 468         struct batadv_bla_claim *claim;
 469         struct batadv_bla_backbone_gw *backbone_gw;
 470         int i;
 471
 472         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 473                    "bla_answer_request(): received a claim request, send all of our own claims again\n");
 474
 475         backbone_gw = batadv_backbone_hash_find(bat_priv,
 476                                                 primary_if->net_dev->dev_addr,
 477                                                 vid);
 478         if (!backbone_gw)
 479                 return;
 480
 481         hash = bat_priv->bla.claim_hash;
 482         for (i = 0; i < hash->size; i++) {
 483                 head = &hash->table[i];
 484
 485                 rcu_read_lock();
 486                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
 487                         /* only own claims are interesting */
 488                         if (claim->backbone_gw != backbone_gw)
 489                                 continue;
 490
 491                         batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
 492                                               BATADV_CLAIM_TYPE_CLAIM);
 493                 }
 494                 rcu_read_unlock();
 495         }
 496
 497         /* finally, send an announcement frame */
 498         batadv_bla_send_announce(bat_priv, backbone_gw);
 499         batadv_backbone_gw_free_ref(backbone_gw);
 500 }
 501
 502 /**
 503  * batadv_bla_send_request - send a request to repeat claims
 504  * @backbone_gw: the backbone gateway from whom we are out of sync
 505  *
 506  * When the crc is wrong, ask the backbone gateway for a full table update.
 507  * After the request, it will repeat all of his own claims and finally
 508  * send an announcement claim with which we can check again.
 509  */
 510 static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw)
 511 {
 512         /* first, remove all old entries */
 513         batadv_bla_del_backbone_claims(backbone_gw);
 514
 515         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 516                    "Sending REQUEST to %pM\n", backbone_gw->orig);
 517
 518         /* send request */
 519         batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 520                               backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
 521
 522         /* no local broadcasts should be sent or received, for now. */
 523         if (!atomic_read(&backbone_gw->request_sent)) {
 524                 atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
 525                 atomic_set(&backbone_gw->request_sent, 1);
 526         }
 527 }
 528
 529 /**
 530  * batadv_bla_send_announce
 531  * @bat_priv: the bat priv with all the soft interface information
 532  * @backbone_gw: our backbone gateway which should be announced
 533  *
 534  * This function sends an announcement. It is called from multiple
 535  * places.
 536  */
 537 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 538                                      struct batadv_bla_backbone_gw *backbone_gw)
 539 {
 540         uint8_t mac[ETH_ALEN];
 541         __be16 crc;
 542
 543         memcpy(mac, batadv_announce_mac, 4);
 544         crc = htons(backbone_gw->crc);
 545         memcpy(&mac[4], &crc, 2);
 546
 547         batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
 548                               BATADV_CLAIM_TYPE_ANNOUNCE);
 549 }
 550
 551 /**
 552  * batadv_bla_add_claim - Adds a claim in the claim hash
 553  * @bat_priv: the bat priv with all the soft interface information
 554  * @mac: the mac address of the claim
 555  * @vid: the VLAN ID of the frame
 556  * @backbone_gw: the backbone gateway which claims it
 557  */
 558 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
 559                                  const uint8_t *mac, const unsigned short vid,
 560                                  struct batadv_bla_backbone_gw *backbone_gw)
 561 {
 562         struct batadv_bla_claim *claim;
 563         struct batadv_bla_claim search_claim;
 564         int hash_added;
 565
 566         ether_addr_copy(search_claim.addr, mac);
 567         search_claim.vid = vid;
 568         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 569
 570         /* create a new claim entry if it does not exist yet. */
 571         if (!claim) {
 572                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 573                 if (!claim)
 574                         return;
 575
 576                 ether_addr_copy(claim->addr, mac);
 577                 claim->vid = vid;
 578                 claim->lasttime = jiffies;
 579                 claim->backbone_gw = backbone_gw;
 580
 581                 atomic_set(&claim->refcount, 2);
 582                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 583                            "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 584                            mac, BATADV_PRINT_VID(vid));
 585                 hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
 586                                              batadv_compare_claim,
 587                                              batadv_choose_claim, claim,
 588                                              &claim->hash_entry);
 589
 590                 if (unlikely(hash_added != 0)) {
 591                         /* only local changes happened. */
 592                         kfree(claim);
 593                         return;
 594                 }
 595         } else {
 596                 claim->lasttime = jiffies;
 597                 if (claim->backbone_gw == backbone_gw)
 598                         /* no need to register a new backbone */
 599                         goto claim_free_ref;
 600
 601                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 602                            "bla_add_claim(): changing ownership for %pM, vid %d\n",
 603                            mac, BATADV_PRINT_VID(vid));
 604
 605                 claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 606                 batadv_backbone_gw_free_ref(claim->backbone_gw);
 607         }
 608         /* set (new) backbone gw */
 609         atomic_inc(&backbone_gw->refcount);
 610         claim->backbone_gw = backbone_gw;
 611
 612         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 613         backbone_gw->lasttime = jiffies;
 614
 615 claim_free_ref:
 616         batadv_claim_free_ref(claim);
 617 }
 618
 619 /* Delete a claim from the claim hash which has the
 620  * given mac address and vid.
 621  */
 622 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
 623                                  const uint8_t *mac, const unsigned short vid)
 624 {
 625         struct batadv_bla_claim search_claim, *claim;
 626
 627         ether_addr_copy(search_claim.addr, mac);
 628         search_claim.vid = vid;
 629         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 630         if (!claim)
 631                 return;
 632
 633         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
 634                    mac, BATADV_PRINT_VID(vid));
 635
 636         batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
 637                            batadv_choose_claim, claim);
 638         batadv_claim_free_ref(claim); /* reference from the hash is gone */
 639
 640         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 641
 642         /* don't need the reference from hash_find() anymore */
 643         batadv_claim_free_ref(claim);
 644 }
 645
 646 /* check for ANNOUNCE frame, return 1 if handled */
 647 static int batadv_handle_announce(struct batadv_priv *bat_priv,
 648                                   uint8_t *an_addr, uint8_t *backbone_addr,
 649                                   unsigned short vid)
 650 {
 651         struct batadv_bla_backbone_gw *backbone_gw;
 652         uint16_t crc;
 653
 654         if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 655                 return 0;
 656
 657         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 658                                                  false);
 659
 660         if (unlikely(!backbone_gw))
 661                 return 1;
 662
 663
 664         /* handle as ANNOUNCE frame */
 665         backbone_gw->lasttime = jiffies;
 666         crc = ntohs(*((__be16 *)(&an_addr[4])));
 667
 668         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 669                    "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
 670                    BATADV_PRINT_VID(vid), backbone_gw->orig, crc);
 671
 672         if (backbone_gw->crc != crc) {
 673                 batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 674                            "handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
 675                            backbone_gw->orig,
 676                            BATADV_PRINT_VID(backbone_gw->vid),
 677                            backbone_gw->crc, crc);
 678
 679                 batadv_bla_send_request(backbone_gw);
 680         } else {
 681                 /* if we have sent a request and the crc was OK,
 682                  * we can allow traffic again.
 683                  */
 684                 if (atomic_read(&backbone_gw->request_sent)) {
 685                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
 686                         atomic_set(&backbone_gw->request_sent, 0);
 687                 }
 688         }
 689
 690         batadv_backbone_gw_free_ref(backbone_gw);
 691         return 1;
 692 }
 693
 694 /* check for REQUEST frame, return 1 if handled */
 695 static int batadv_handle_request(struct batadv_priv *bat_priv,
 696                                  struct batadv_hard_iface *primary_if,
 697                                  uint8_t *backbone_addr,
 698                                  struct ethhdr *ethhdr, unsigned short vid)
 699 {
 700         /* check for REQUEST frame */
 701         if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
 702                 return 0;
 703
 704         /* sanity check, this should not happen on a normal switch,
 705          * we ignore it in this case.
 706          */
 707         if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 708                 return 1;
 709
 710         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 711                    "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 712                    BATADV_PRINT_VID(vid), ethhdr->h_source);
 713
 714         batadv_bla_answer_request(bat_priv, primary_if, vid);
 715         return 1;
 716 }
 717
 718 /* check for UNCLAIM frame, return 1 if handled */
 719 static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
 720                                  struct batadv_hard_iface *primary_if,
 721                                  uint8_t *backbone_addr,
 722                                  uint8_t *claim_addr, unsigned short vid)
 723 {
 724         struct batadv_bla_backbone_gw *backbone_gw;
 725
 726         /* unclaim in any case if it is our own */
 727         if (primary_if && batadv_compare_eth(backbone_addr,
 728                                              primary_if->net_dev->dev_addr))
 729                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 730                                       BATADV_CLAIM_TYPE_UNCLAIM);
 731
 732         backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
 733
 734         if (!backbone_gw)
 735                 return 1;
 736
 737         /* this must be an UNCLAIM frame */
 738         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 739                    "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 740                    claim_addr, BATADV_PRINT_VID(vid), backbone_gw->orig);
 741
 742         batadv_bla_del_claim(bat_priv, claim_addr, vid);
 743         batadv_backbone_gw_free_ref(backbone_gw);
 744         return 1;
 745 }
 746
 747 /* check for CLAIM frame, return 1 if handled */
 748 static int batadv_handle_claim(struct batadv_priv *bat_priv,
 749                                struct batadv_hard_iface *primary_if,
 750                                uint8_t *backbone_addr, uint8_t *claim_addr,
 751                                unsigned short vid)
 752 {
 753         struct batadv_bla_backbone_gw *backbone_gw;
 754
 755         /* register the gateway if not yet available, and add the claim. */
 756
 757         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 758                                                  false);
 759
 760         if (unlikely(!backbone_gw))
 761                 return 1;
 762
 763         /* this must be a CLAIM frame */
 764         batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 765         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 766                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 767                                       BATADV_CLAIM_TYPE_CLAIM);
 768
 769         /* TODO: we could call something like tt_local_del() here. */
 770
 771         batadv_backbone_gw_free_ref(backbone_gw);
 772         return 1;
 773 }
 774
 775 /**
 776  * batadv_check_claim_group
 777  * @bat_priv: the bat priv with all the soft interface information
 778  * @hw_src: the Hardware source in the ARP Header
 779  * @hw_dst: the Hardware destination in the ARP Header
 780  * @ethhdr: pointer to the Ethernet header of the claim frame
 781  *
 782  * checks if it is a claim packet and if its on the same group.
 783  * This function also applies the group ID of the sender
 784  * if it is in the same mesh.
 785  *
 786  * returns:
 787  *      2  - if it is a claim packet and on the same group
 788  *      1  - if is a claim packet from another group
 789  *      0  - if it is not a claim packet
 790  */
 791 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 792                                     struct batadv_hard_iface *primary_if,
 793                                     uint8_t *hw_src, uint8_t *hw_dst,
 794                                     struct ethhdr *ethhdr)
 795 {
 796         uint8_t *backbone_addr;
 797         struct batadv_orig_node *orig_node;
 798         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 799
 800         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 801         bla_dst_own = &bat_priv->bla.claim_dest;
 802
 803         /* if announcement packet, use the source,
 804          * otherwise assume it is in the hw_src
 805          */
 806         switch (bla_dst->type) {
 807         case BATADV_CLAIM_TYPE_CLAIM:
 808                 backbone_addr = hw_src;
 809                 break;
 810         case BATADV_CLAIM_TYPE_REQUEST:
 811         case BATADV_CLAIM_TYPE_ANNOUNCE:
 812         case BATADV_CLAIM_TYPE_UNCLAIM:
 813                 backbone_addr = ethhdr->h_source;
 814                 break;
 815         default:
 816                 return 0;
 817         }
 818
 819         /* don't accept claim frames from ourselves */
 820         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 821                 return 0;
 822
 823         /* if its already the same group, it is fine. */
 824         if (bla_dst->group == bla_dst_own->group)
 825                 return 2;
 826
 827         /* lets see if this originator is in our mesh */
 828         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 829
 830         /* dont accept claims from gateways which are not in
 831          * the same mesh or group.
 832          */
 833         if (!orig_node)
 834                 return 1;
 835
 836         /* if our mesh friends mac is bigger, use it for ourselves. */
 837         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 838                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 839                            "taking other backbones claim group: %#.4x\n",
 840                            ntohs(bla_dst->group));
 841                 bla_dst_own->group = bla_dst->group;
 842         }
 843
 844         batadv_orig_node_free_ref(orig_node);
 845
 846         return 2;
 847 }
 848
 849
 850 /**
 851  * batadv_bla_process_claim
 852  * @bat_priv: the bat priv with all the soft interface information
 853  * @skb: the frame to be checked
 854  *
 855  * Check if this is a claim frame, and process it accordingly.
 856  *
 857  * returns 1 if it was a claim frame, otherwise return 0 to
 858  * tell the callee that it can use the frame on its own.
 859  */
 860 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 861                                     struct batadv_hard_iface *primary_if,
 862                                     struct sk_buff *skb)
 863 {
 864         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 865         uint8_t *hw_src, *hw_dst;
 866         struct vlan_hdr *vhdr, vhdr_buf;
 867         struct ethhdr *ethhdr;
 868         struct arphdr *arphdr;
 869         unsigned short vid;
 870         int vlan_depth = 0;
 871         __be16 proto;
 872         int headlen;
 873         int ret;
 874
 875         vid = batadv_get_vid(skb, 0);
 876         ethhdr = eth_hdr(skb);
 877
 878         proto = ethhdr->h_proto;
 879         headlen = ETH_HLEN;
 880         if (vid & BATADV_VLAN_HAS_TAG) {
 881                 /* Traverse the VLAN/Ethertypes.
 882                  *
 883                  * At this point it is known that the first protocol is a VLAN
 884                  * header, so start checking at the encapsulated protocol.
 885                  *
 886                  * The depth of the VLAN headers is recorded to drop BLA claim
 887                  * frames encapsulated into multiple VLAN headers (QinQ).
 888                  */
 889                 do {
 890                         vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
 891                                                   &vhdr_buf);
 892                         if (!vhdr)
 893                                 return 0;
 894
 895                         proto = vhdr->h_vlan_encapsulated_proto;
 896                         headlen += VLAN_HLEN;
 897                         vlan_depth++;
 898                 } while (proto == htons(ETH_P_8021Q));
 899         }
 900
 901         if (proto != htons(ETH_P_ARP))
 902                 return 0; /* not a claim frame */
 903
 904         /* this must be a ARP frame. check if it is a claim. */
 905
 906         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 907                 return 0;
 908
 909         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 910         ethhdr = eth_hdr(skb);
 911         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 912
 913         /* Check whether the ARP frame carries a valid
 914          * IP information
 915          */
 916         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 917                 return 0;
 918         if (arphdr->ar_pro != htons(ETH_P_IP))
 919                 return 0;
 920         if (arphdr->ar_hln != ETH_ALEN)
 921                 return 0;
 922         if (arphdr->ar_pln != 4)
 923                 return 0;
 924
 925         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 926         hw_dst = hw_src + ETH_ALEN + 4;
 927         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 928         bla_dst_own = &bat_priv->bla.claim_dest;
 929
 930         /* check if it is a claim frame in general */
 931         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 932                    sizeof(bla_dst->magic)) != 0)
 933                 return 0;
 934
 935         /* check if there is a claim frame encapsulated deeper in (QinQ) and
 936          * drop that, as this is not supported by BLA but should also not be
 937          * sent via the mesh.
 938          */
 939         if (vlan_depth > 1)
 940                 return 1;
 941
 942         /* check if it is a claim frame. */
 943         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 944                                        ethhdr);
 945         if (ret == 1)
 946                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 947                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 948                            ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src,
 949                            hw_dst);
 950
 951         if (ret < 2)
 952                 return ret;
 953
 954         /* become a backbone gw ourselves on this vlan if not happened yet */
 955         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 956
 957         /* check for the different types of claim frames ... */
 958         switch (bla_dst->type) {
 959         case BATADV_CLAIM_TYPE_CLAIM:
 960                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 961                                         ethhdr->h_source, vid))
 962                         return 1;
 963                 break;
 964         case BATADV_CLAIM_TYPE_UNCLAIM:
 965                 if (batadv_handle_unclaim(bat_priv, primary_if,
 966                                           ethhdr->h_source, hw_src, vid))
 967                         return 1;
 968                 break;
 969
 970         case BATADV_CLAIM_TYPE_ANNOUNCE:
 971                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
 972                                            vid))
 973                         return 1;
 974                 break;
 975         case BATADV_CLAIM_TYPE_REQUEST:
 976                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
 977                                           vid))
 978                         return 1;
 979                 break;
 980         }
 981
 982         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 983                    "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",
 984                    ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src, hw_dst);
 985         return 1;
 986 }
 987
 988 /* Check when we last heard from other nodes, and remove them in case of
 989  * a time out, or clean all backbone gws if now is set.
 990  */
 991 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
 992 {
 993         struct batadv_bla_backbone_gw *backbone_gw;
 994         struct hlist_node *node_tmp;
 995         struct hlist_head *head;
 996         struct batadv_hashtable *hash;
 997         spinlock_t *list_lock;  /* protects write access to the hash lists */
 998         int i;
 999
1000         hash = bat_priv->bla.backbone_hash;
1001         if (!hash)
1002                 return;
1003
1004         for (i = 0; i < hash->size; i++) {
1005                 head = &hash->table[i];
1006                 list_lock = &hash->list_locks[i];
1007
1008                 spin_lock_bh(list_lock);
1009                 hlist_for_each_entry_safe(backbone_gw, node_tmp,
1010                                           head, hash_entry) {
1011                         if (now)
1012                                 goto purge_now;
1013                         if (!batadv_has_timed_out(backbone_gw->lasttime,
1014                                                   BATADV_BLA_BACKBONE_TIMEOUT))
1015                                 continue;
1016
1017                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
1018                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
1019                                    backbone_gw->orig);
1020
1021 purge_now:
1022                         /* don't wait for the pending request anymore */
1023                         if (atomic_read(&backbone_gw->request_sent))
1024                                 atomic_dec(&bat_priv->bla.num_requests);
1025
1026                         batadv_bla_del_backbone_claims(backbone_gw);
1027
1028                         hlist_del_rcu(&backbone_gw->hash_entry);
1029                         batadv_backbone_gw_free_ref(backbone_gw);
1030                 }
1031                 spin_unlock_bh(list_lock);
1032         }
1033 }
1034
1035 /**
1036  * batadv_bla_purge_claims
1037  * @bat_priv: the bat priv with all the soft interface information
1038  * @primary_if: the selected primary interface, may be NULL if now is set
1039  * @now: whether the whole hash shall be wiped now
1040  *
1041  * Check when we heard last time from our own claims, and remove them in case of
1042  * a time out, or clean all claims if now is set
1043  */
1044 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
1045                                     struct batadv_hard_iface *primary_if,
1046                                     int now)
1047 {
1048         struct batadv_bla_claim *claim;
1049         struct hlist_head *head;
1050         struct batadv_hashtable *hash;
1051         int i;
1052
1053         hash = bat_priv->bla.claim_hash;
1054         if (!hash)
1055                 return;
1056
1057         for (i = 0; i < hash->size; i++) {
1058                 head = &hash->table[i];
1059
1060                 rcu_read_lock();
1061                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1062                         if (now)
1063                                 goto purge_now;
1064                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1065                                                 primary_if->net_dev->dev_addr))
1066                                 continue;
1067                         if (!batadv_has_timed_out(claim->lasttime,
1068                                                   BATADV_BLA_CLAIM_TIMEOUT))
1069                                 continue;
1070
1071                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1072                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1073                                    claim->addr, claim->vid);
1074
1075 purge_now:
1076                         batadv_handle_unclaim(bat_priv, primary_if,
1077                                               claim->backbone_gw->orig,
1078                                               claim->addr, claim->vid);
1079                 }
1080                 rcu_read_unlock();
1081         }
1082 }
1083
1084 /**
1085  * batadv_bla_update_orig_address
1086  * @bat_priv: the bat priv with all the soft interface information
1087  * @primary_if: the new selected primary_if
1088  * @oldif: the old primary interface, may be NULL
1089  *
1090  * Update the backbone gateways when the own orig address changes.
1091  */
1092 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1093                                     struct batadv_hard_iface *primary_if,
1094                                     struct batadv_hard_iface *oldif)
1095 {
1096         struct batadv_bla_backbone_gw *backbone_gw;
1097         struct hlist_head *head;
1098         struct batadv_hashtable *hash;
1099         __be16 group;
1100         int i;
1101
1102         /* reset bridge loop avoidance group id */
1103         group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1104         bat_priv->bla.claim_dest.group = group;
1105
1106         /* purge everything when bridge loop avoidance is turned off */
1107         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1108                 oldif = NULL;
1109
1110         if (!oldif) {
1111                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1112                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1113                 return;
1114         }
1115
1116         hash = bat_priv->bla.backbone_hash;
1117         if (!hash)
1118                 return;
1119
1120         for (i = 0; i < hash->size; i++) {
1121                 head = &hash->table[i];
1122
1123                 rcu_read_lock();
1124                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1125                         /* own orig still holds the old value. */
1126                         if (!batadv_compare_eth(backbone_gw->orig,
1127                                                 oldif->net_dev->dev_addr))
1128                                 continue;
1129
1130                         ether_addr_copy(backbone_gw->orig,
1131                                         primary_if->net_dev->dev_addr);
1132                         /* send an announce frame so others will ask for our
1133                          * claims and update their tables.
1134                          */
1135                         batadv_bla_send_announce(bat_priv, backbone_gw);
1136                 }
1137                 rcu_read_unlock();
1138         }
1139 }
1140
1141 /* periodic work to do:
1142  *  * purge structures when they are too old
1143  *  * send announcements
1144  */
1145 static void batadv_bla_periodic_work(struct work_struct *work)
1146 {
1147         struct delayed_work *delayed_work;
1148         struct batadv_priv *bat_priv;
1149         struct batadv_priv_bla *priv_bla;
1150         struct hlist_head *head;
1151         struct batadv_bla_backbone_gw *backbone_gw;
1152         struct batadv_hashtable *hash;
1153         struct batadv_hard_iface *primary_if;
1154         int i;
1155
1156         delayed_work = container_of(work, struct delayed_work, work);
1157         priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1158         bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1159         primary_if = batadv_primary_if_get_selected(bat_priv);
1160         if (!primary_if)
1161                 goto out;
1162
1163         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1164         batadv_bla_purge_backbone_gw(bat_priv, 0);
1165
1166         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1167                 goto out;
1168
1169         hash = bat_priv->bla.backbone_hash;
1170         if (!hash)
1171                 goto out;
1172
1173         for (i = 0; i < hash->size; i++) {
1174                 head = &hash->table[i];
1175
1176                 rcu_read_lock();
1177                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1178                         if (!batadv_compare_eth(backbone_gw->orig,
1179                                                 primary_if->net_dev->dev_addr))
1180                                 continue;
1181
1182                         backbone_gw->lasttime = jiffies;
1183
1184                         batadv_bla_send_announce(bat_priv, backbone_gw);
1185
1186                         /* request_sent is only set after creation to avoid
1187                          * problems when we are not yet known as backbone gw
1188                          * in the backbone.
1189                          *
1190                          * We can reset this now after we waited some periods
1191                          * to give bridge forward delays and bla group forming
1192                          * some grace time.
1193                          */
1194
1195                         if (atomic_read(&backbone_gw->request_sent) == 0)
1196                                 continue;
1197
1198                         if (!atomic_dec_and_test(&backbone_gw->wait_periods))
1199                                 continue;
1200
1201                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
1202                         atomic_set(&backbone_gw->request_sent, 0);
1203                 }
1204                 rcu_read_unlock();
1205         }
1206 out:
1207         if (primary_if)
1208                 batadv_hardif_free_ref(primary_if);
1209
1210         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1211                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1212 }
1213
1214 /* The hash for claim and backbone hash receive the same key because they
1215  * are getting initialized by hash_new with the same key. Reinitializing
1216  * them with to different keys to allow nested locking without generating
1217  * lockdep warnings
1218  */
1219 static struct lock_class_key batadv_claim_hash_lock_class_key;
1220 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1221
1222 /* initialize all bla structures */
1223 int batadv_bla_init(struct batadv_priv *bat_priv)
1224 {
1225         int i;
1226         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1227         struct batadv_hard_iface *primary_if;
1228         uint16_t crc;
1229         unsigned long entrytime;
1230
1231         spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1232
1233         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1234
1235         /* setting claim destination address */
1236         memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1237         bat_priv->bla.claim_dest.type = 0;
1238         primary_if = batadv_primary_if_get_selected(bat_priv);
1239         if (primary_if) {
1240                 crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1241                 bat_priv->bla.claim_dest.group = htons(crc);
1242                 batadv_hardif_free_ref(primary_if);
1243         } else {
1244                 bat_priv->bla.claim_dest.group = 0; /* will be set later */
1245         }
1246
1247         /* initialize the duplicate list */
1248         entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1249         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1250                 bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1251         bat_priv->bla.bcast_duplist_curr = 0;
1252
1253         if (bat_priv->bla.claim_hash)
1254                 return 0;
1255
1256         bat_priv->bla.claim_hash = batadv_hash_new(128);
1257         bat_priv->bla.backbone_hash = batadv_hash_new(32);
1258
1259         if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
1260                 return -ENOMEM;
1261
1262         batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1263                                    &batadv_claim_hash_lock_class_key);
1264         batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1265                                    &batadv_backbone_hash_lock_class_key);
1266
1267         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1268
1269         INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1270
1271         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1272                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1273         return 0;
1274 }
1275
1276 /**
1277  * batadv_bla_check_bcast_duplist
1278  * @bat_priv: the bat priv with all the soft interface information
1279  * @skb: contains the bcast_packet to be checked
1280  *
1281  * check if it is on our broadcast list. Another gateway might
1282  * have sent the same packet because it is connected to the same backbone,
1283  * so we have to remove this duplicate.
1284  *
1285  * This is performed by checking the CRC, which will tell us
1286  * with a good chance that it is the same packet. If it is furthermore
1287  * sent by another host, drop it. We allow equal packets from
1288  * the same host however as this might be intended.
1289  */
1290 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1291                                    struct sk_buff *skb)
1292 {
1293         int i, curr, ret = 0;
1294         __be32 crc;
1295         struct batadv_bcast_packet *bcast_packet;
1296         struct batadv_bcast_duplist_entry *entry;
1297
1298         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1299
1300         /* calculate the crc ... */
1301         crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
1302
1303         spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1304
1305         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1306                 curr = (bat_priv->bla.bcast_duplist_curr + i);
1307                 curr %= BATADV_DUPLIST_SIZE;
1308                 entry = &bat_priv->bla.bcast_duplist[curr];
1309
1310                 /* we can stop searching if the entry is too old ;
1311                  * later entries will be even older
1312                  */
1313                 if (batadv_has_timed_out(entry->entrytime,
1314                                          BATADV_DUPLIST_TIMEOUT))
1315                         break;
1316
1317                 if (entry->crc != crc)
1318                         continue;
1319
1320                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1321                         continue;
1322
1323                 /* this entry seems to match: same crc, not too old,
1324                  * and from another gw. therefore return 1 to forbid it.
1325                  */
1326                 ret = 1;
1327                 goto out;
1328         }
1329         /* not found, add a new entry (overwrite the oldest entry)
1330          * and allow it, its the first occurence.
1331          */
1332         curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1333         curr %= BATADV_DUPLIST_SIZE;
1334         entry = &bat_priv->bla.bcast_duplist[curr];
1335         entry->crc = crc;
1336         entry->entrytime = jiffies;
1337         ether_addr_copy(entry->orig, bcast_packet->orig);
1338         bat_priv->bla.bcast_duplist_curr = curr;
1339
1340 out:
1341         spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1342
1343         return ret;
1344 }
1345
1346
1347
1348 /**
1349  * batadv_bla_is_backbone_gw_orig
1350  * @bat_priv: the bat priv with all the soft interface information
1351  * @orig: originator mac address
1352  * @vid: VLAN identifier
1353  *
1354  * Check if the originator is a gateway for the VLAN identified by vid.
1355  *
1356  * Returns true if orig is a backbone for this vid, false otherwise.
1357  */
1358 bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig,
1359                                     unsigned short vid)
1360 {
1361         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1362         struct hlist_head *head;
1363         struct batadv_bla_backbone_gw *backbone_gw;
1364         int i;
1365
1366         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1367                 return false;
1368
1369         if (!hash)
1370                 return false;
1371
1372         for (i = 0; i < hash->size; i++) {
1373                 head = &hash->table[i];
1374
1375                 rcu_read_lock();
1376                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1377                         if (batadv_compare_eth(backbone_gw->orig, orig) &&
1378                             backbone_gw->vid == vid) {
1379                                 rcu_read_unlock();
1380                                 return true;
1381                         }
1382                 }
1383                 rcu_read_unlock();
1384         }
1385
1386         return false;
1387 }
1388
1389
1390 /**
1391  * batadv_bla_is_backbone_gw
1392  * @skb: the frame to be checked
1393  * @orig_node: the orig_node of the frame
1394  * @hdr_size: maximum length of the frame
1395  *
1396  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1397  * if the orig_node is also a gateway on the soft interface, otherwise it
1398  * returns 0.
1399  */
1400 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1401                               struct batadv_orig_node *orig_node, int hdr_size)
1402 {
1403         struct batadv_bla_backbone_gw *backbone_gw;
1404         unsigned short vid;
1405
1406         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1407                 return 0;
1408
1409         /* first, find out the vid. */
1410         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1411                 return 0;
1412
1413         vid = batadv_get_vid(skb, hdr_size);
1414
1415         /* see if this originator is a backbone gw for this VLAN */
1416         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1417                                                 orig_node->orig, vid);
1418         if (!backbone_gw)
1419                 return 0;
1420
1421         batadv_backbone_gw_free_ref(backbone_gw);
1422         return 1;
1423 }
1424
1425 /* free all bla structures (for softinterface free or module unload) */
1426 void batadv_bla_free(struct batadv_priv *bat_priv)
1427 {
1428         struct batadv_hard_iface *primary_if;
1429
1430         cancel_delayed_work_sync(&bat_priv->bla.work);
1431         primary_if = batadv_primary_if_get_selected(bat_priv);
1432
1433         if (bat_priv->bla.claim_hash) {
1434                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1435                 batadv_hash_destroy(bat_priv->bla.claim_hash);
1436                 bat_priv->bla.claim_hash = NULL;
1437         }
1438         if (bat_priv->bla.backbone_hash) {
1439                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1440                 batadv_hash_destroy(bat_priv->bla.backbone_hash);
1441                 bat_priv->bla.backbone_hash = NULL;
1442         }
1443         if (primary_if)
1444                 batadv_hardif_free_ref(primary_if);
1445 }
1446
1447 /**
1448  * batadv_bla_rx
1449  * @bat_priv: the bat priv with all the soft interface information
1450  * @skb: the frame to be checked
1451  * @vid: the VLAN ID of the frame
1452  * @is_bcast: the packet came in a broadcast packet type.
1453  *
1454  * bla_rx avoidance checks if:
1455  *  * we have to race for a claim
1456  *  * if the frame is allowed on the LAN
1457  *
1458  * in these cases, the skb is further handled by this function and
1459  * returns 1, otherwise it returns 0 and the caller shall further
1460  * process the skb.
1461  */
1462 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1463                   unsigned short vid, bool is_bcast)
1464 {
1465         struct ethhdr *ethhdr;
1466         struct batadv_bla_claim search_claim, *claim = NULL;
1467         struct batadv_hard_iface *primary_if;
1468         int ret;
1469
1470         ethhdr = eth_hdr(skb);
1471
1472         primary_if = batadv_primary_if_get_selected(bat_priv);
1473         if (!primary_if)
1474                 goto handled;
1475
1476         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1477                 goto allow;
1478
1479
1480         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1481                 /* don't allow broadcasts while requests are in flight */
1482                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1483                         goto handled;
1484
1485         ether_addr_copy(search_claim.addr, ethhdr->h_source);
1486         search_claim.vid = vid;
1487         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1488
1489         if (!claim) {
1490                 /* possible optimization: race for a claim */
1491                 /* No claim exists yet, claim it for us!
1492                  */
1493                 batadv_handle_claim(bat_priv, primary_if,
1494                                     primary_if->net_dev->dev_addr,
1495                                     ethhdr->h_source, vid);
1496                 goto allow;
1497         }
1498
1499         /* if it is our own claim ... */
1500         if (batadv_compare_eth(claim->backbone_gw->orig,
1501                                primary_if->net_dev->dev_addr)) {
1502                 /* ... allow it in any case */
1503                 claim->lasttime = jiffies;
1504                 goto allow;
1505         }
1506
1507         /* if it is a broadcast ... */
1508         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1509                 /* ... drop it. the responsible gateway is in charge.
1510                  *
1511                  * We need to check is_bcast because with the gateway
1512                  * feature, broadcasts (like DHCP requests) may be sent
1513                  * using a unicast packet type.
1514                  */
1515                 goto handled;
1516         } else {
1517                 /* seems the client considers us as its best gateway.
1518                  * send a claim and update the claim table
1519                  * immediately.
1520                  */
1521                 batadv_handle_claim(bat_priv, primary_if,
1522                                     primary_if->net_dev->dev_addr,
1523                                     ethhdr->h_source, vid);
1524                 goto allow;
1525         }
1526 allow:
1527         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1528         ret = 0;
1529         goto out;
1530
1531 handled:
1532         kfree_skb(skb);
1533         ret = 1;
1534
1535 out:
1536         if (primary_if)
1537                 batadv_hardif_free_ref(primary_if);
1538         if (claim)
1539                 batadv_claim_free_ref(claim);
1540         return ret;
1541 }
1542
1543 /**
1544  * batadv_bla_tx
1545  * @bat_priv: the bat priv with all the soft interface information
1546  * @skb: the frame to be checked
1547  * @vid: the VLAN ID of the frame
1548  *
1549  * bla_tx checks if:
1550  *  * a claim was received which has to be processed
1551  *  * the frame is allowed on the mesh
1552  *
1553  * in these cases, the skb is further handled by this function and
1554  * returns 1, otherwise it returns 0 and the caller shall further
1555  * process the skb.
1556  *
1557  * This call might reallocate skb data.
1558  */
1559 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1560                   unsigned short vid)
1561 {
1562         struct ethhdr *ethhdr;
1563         struct batadv_bla_claim search_claim, *claim = NULL;
1564         struct batadv_hard_iface *primary_if;
1565         int ret = 0;
1566
1567         primary_if = batadv_primary_if_get_selected(bat_priv);
1568         if (!primary_if)
1569                 goto out;
1570
1571         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1572                 goto allow;
1573
1574         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1575                 goto handled;
1576
1577         ethhdr = eth_hdr(skb);
1578
1579         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1580                 /* don't allow broadcasts while requests are in flight */
1581                 if (is_multicast_ether_addr(ethhdr->h_dest))
1582                         goto handled;
1583
1584         ether_addr_copy(search_claim.addr, ethhdr->h_source);
1585         search_claim.vid = vid;
1586
1587         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1588
1589         /* if no claim exists, allow it. */
1590         if (!claim)
1591                 goto allow;
1592
1593         /* check if we are responsible. */
1594         if (batadv_compare_eth(claim->backbone_gw->orig,
1595                                primary_if->net_dev->dev_addr)) {
1596                 /* if yes, the client has roamed and we have
1597                  * to unclaim it.
1598                  */
1599                 batadv_handle_unclaim(bat_priv, primary_if,
1600                                       primary_if->net_dev->dev_addr,
1601                                       ethhdr->h_source, vid);
1602                 goto allow;
1603         }
1604
1605         /* check if it is a multicast/broadcast frame */
1606         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1607                 /* drop it. the responsible gateway has forwarded it into
1608                  * the backbone network.
1609                  */
1610                 goto handled;
1611         } else {
1612                 /* we must allow it. at least if we are
1613                  * responsible for the DESTINATION.
1614                  */
1615                 goto allow;
1616         }
1617 allow:
1618         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1619         ret = 0;
1620         goto out;
1621 handled:
1622         ret = 1;
1623 out:
1624         if (primary_if)
1625                 batadv_hardif_free_ref(primary_if);
1626         if (claim)
1627                 batadv_claim_free_ref(claim);
1628         return ret;
1629 }
1630
1631 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1632 {
1633         struct net_device *net_dev = (struct net_device *)seq->private;
1634         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1635         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
1636         struct batadv_bla_claim *claim;
1637         struct batadv_hard_iface *primary_if;
1638         struct hlist_head *head;
1639         uint32_t i;
1640         bool is_own;
1641         uint8_t *primary_addr;
1642
1643         primary_if = batadv_seq_print_text_primary_if_get(seq);
1644         if (!primary_if)
1645                 goto out;
1646
1647         primary_addr = primary_if->net_dev->dev_addr;
1648         seq_printf(seq,
1649                    "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
1650                    net_dev->name, primary_addr,
1651                    ntohs(bat_priv->bla.claim_dest.group));
1652         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-6s)\n",
1653                    "Client", "VID", "Originator", "CRC");
1654         for (i = 0; i < hash->size; i++) {
1655                 head = &hash->table[i];
1656
1657                 rcu_read_lock();
1658                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1659                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1660                                                     primary_addr);
1661                         seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n",
1662                                    claim->addr, BATADV_PRINT_VID(claim->vid),
1663                                    claim->backbone_gw->orig,
1664                                    (is_own ? 'x' : ' '),
1665                                    claim->backbone_gw->crc);
1666                 }
1667                 rcu_read_unlock();
1668         }
1669 out:
1670         if (primary_if)
1671                 batadv_hardif_free_ref(primary_if);
1672         return 0;
1673 }
1674
1675 int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
1676 {
1677         struct net_device *net_dev = (struct net_device *)seq->private;
1678         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1679         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1680         struct batadv_bla_backbone_gw *backbone_gw;
1681         struct batadv_hard_iface *primary_if;
1682         struct hlist_head *head;
1683         int secs, msecs;
1684         uint32_t i;
1685         bool is_own;
1686         uint8_t *primary_addr;
1687
1688         primary_if = batadv_seq_print_text_primary_if_get(seq);
1689         if (!primary_if)
1690                 goto out;
1691
1692         primary_addr = primary_if->net_dev->dev_addr;
1693         seq_printf(seq,
1694                    "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
1695                    net_dev->name, primary_addr,
1696                    ntohs(bat_priv->bla.claim_dest.group));
1697         seq_printf(seq, "   %-17s    %-5s %-9s (%-6s)\n",
1698                    "Originator", "VID", "last seen", "CRC");
1699         for (i = 0; i < hash->size; i++) {
1700                 head = &hash->table[i];
1701
1702                 rcu_read_lock();
1703                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1704                         msecs = jiffies_to_msecs(jiffies -
1705                                                  backbone_gw->lasttime);
1706                         secs = msecs / 1000;
1707                         msecs = msecs % 1000;
1708
1709                         is_own = batadv_compare_eth(backbone_gw->orig,
1710                                                     primary_addr);
1711                         if (is_own)
1712                                 continue;
1713
1714                         seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n",
1715                                    backbone_gw->orig,
1716                                    BATADV_PRINT_VID(backbone_gw->vid), secs,
1717                                    msecs, backbone_gw->crc);
1718                 }
1719                 rcu_read_unlock();
1720         }
1721 out:
1722         if (primary_if)
1723                 batadv_hardif_free_ref(primary_if);
1724         return 0;
1725 }