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         memcpy(search_entry.orig, addr, ETH_ALEN);
 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                 memcpy(ethhdr->h_source, mac, ETH_ALEN);
 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                 memcpy(hw_src, mac, ETH_ALEN);
 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                 memcpy(hw_src, mac, ETH_ALEN);
 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                 memcpy(hw_src, mac, ETH_ALEN);
 337                 memcpy(ethhdr->h_dest, mac, ETH_ALEN);
 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         memcpy(entry->orig, orig, ETH_ALEN);
 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         memcpy(search_claim.addr, mac, ETH_ALEN);
 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                 memcpy(claim->addr, mac, ETH_ALEN);
 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         memcpy(search_claim.addr, mac, ETH_ALEN);
 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         /* check if it is a claim packet in general */
 804         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 805                    sizeof(bla_dst->magic)) != 0)
 806                 return 0;
 807
 808         /* if announcement packet, use the source,
 809          * otherwise assume it is in the hw_src
 810          */
 811         switch (bla_dst->type) {
 812         case BATADV_CLAIM_TYPE_CLAIM:
 813                 backbone_addr = hw_src;
 814                 break;
 815         case BATADV_CLAIM_TYPE_REQUEST:
 816         case BATADV_CLAIM_TYPE_ANNOUNCE:
 817         case BATADV_CLAIM_TYPE_UNCLAIM:
 818                 backbone_addr = ethhdr->h_source;
 819                 break;
 820         default:
 821                 return 0;
 822         }
 823
 824         /* don't accept claim frames from ourselves */
 825         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 826                 return 0;
 827
 828         /* if its already the same group, it is fine. */
 829         if (bla_dst->group == bla_dst_own->group)
 830                 return 2;
 831
 832         /* lets see if this originator is in our mesh */
 833         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 834
 835         /* dont accept claims from gateways which are not in
 836          * the same mesh or group.
 837          */
 838         if (!orig_node)
 839                 return 1;
 840
 841         /* if our mesh friends mac is bigger, use it for ourselves. */
 842         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 843                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 844                            "taking other backbones claim group: %#.4x\n",
 845                            ntohs(bla_dst->group));
 846                 bla_dst_own->group = bla_dst->group;
 847         }
 848
 849         batadv_orig_node_free_ref(orig_node);
 850
 851         return 2;
 852 }
 853
 854
 855 /**
 856  * batadv_bla_process_claim
 857  * @bat_priv: the bat priv with all the soft interface information
 858  * @skb: the frame to be checked
 859  *
 860  * Check if this is a claim frame, and process it accordingly.
 861  *
 862  * returns 1 if it was a claim frame, otherwise return 0 to
 863  * tell the callee that it can use the frame on its own.
 864  */
 865 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 866                                     struct batadv_hard_iface *primary_if,
 867                                     struct sk_buff *skb)
 868 {
 869         struct batadv_bla_claim_dst *bla_dst;
 870         uint8_t *hw_src, *hw_dst;
 871         struct vlan_ethhdr *vhdr;
 872         struct ethhdr *ethhdr;
 873         struct arphdr *arphdr;
 874         unsigned short vid;
 875         __be16 proto;
 876         int headlen;
 877         int ret;
 878
 879         vid = batadv_get_vid(skb, 0);
 880         ethhdr = eth_hdr(skb);
 881
 882         proto = ethhdr->h_proto;
 883         headlen = ETH_HLEN;
 884         if (vid & BATADV_VLAN_HAS_TAG) {
 885                 vhdr = (struct vlan_ethhdr *)ethhdr;
 886                 proto = vhdr->h_vlan_encapsulated_proto;
 887                 headlen += VLAN_HLEN;
 888         }
 889
 890         if (proto != htons(ETH_P_ARP))
 891                 return 0; /* not a claim frame */
 892
 893         /* this must be a ARP frame. check if it is a claim. */
 894
 895         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 896                 return 0;
 897
 898         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 899         ethhdr = eth_hdr(skb);
 900         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 901
 902         /* Check whether the ARP frame carries a valid
 903          * IP information
 904          */
 905         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 906                 return 0;
 907         if (arphdr->ar_pro != htons(ETH_P_IP))
 908                 return 0;
 909         if (arphdr->ar_hln != ETH_ALEN)
 910                 return 0;
 911         if (arphdr->ar_pln != 4)
 912                 return 0;
 913
 914         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 915         hw_dst = hw_src + ETH_ALEN + 4;
 916         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 917
 918         /* check if it is a claim frame. */
 919         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 920                                        ethhdr);
 921         if (ret == 1)
 922                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 923                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 924                            ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src,
 925                            hw_dst);
 926
 927         if (ret < 2)
 928                 return ret;
 929
 930         /* become a backbone gw ourselves on this vlan if not happened yet */
 931         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 932
 933         /* check for the different types of claim frames ... */
 934         switch (bla_dst->type) {
 935         case BATADV_CLAIM_TYPE_CLAIM:
 936                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 937                                         ethhdr->h_source, vid))
 938                         return 1;
 939                 break;
 940         case BATADV_CLAIM_TYPE_UNCLAIM:
 941                 if (batadv_handle_unclaim(bat_priv, primary_if,
 942                                           ethhdr->h_source, hw_src, vid))
 943                         return 1;
 944                 break;
 945
 946         case BATADV_CLAIM_TYPE_ANNOUNCE:
 947                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
 948                                            vid))
 949                         return 1;
 950                 break;
 951         case BATADV_CLAIM_TYPE_REQUEST:
 952                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
 953                                           vid))
 954                         return 1;
 955                 break;
 956         }
 957
 958         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 959                    "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",
 960                    ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src, hw_dst);
 961         return 1;
 962 }
 963
 964 /* Check when we last heard from other nodes, and remove them in case of
 965  * a time out, or clean all backbone gws if now is set.
 966  */
 967 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
 968 {
 969         struct batadv_bla_backbone_gw *backbone_gw;
 970         struct hlist_node *node_tmp;
 971         struct hlist_head *head;
 972         struct batadv_hashtable *hash;
 973         spinlock_t *list_lock;  /* protects write access to the hash lists */
 974         int i;
 975
 976         hash = bat_priv->bla.backbone_hash;
 977         if (!hash)
 978                 return;
 979
 980         for (i = 0; i < hash->size; i++) {
 981                 head = &hash->table[i];
 982                 list_lock = &hash->list_locks[i];
 983
 984                 spin_lock_bh(list_lock);
 985                 hlist_for_each_entry_safe(backbone_gw, node_tmp,
 986                                           head, hash_entry) {
 987                         if (now)
 988                                 goto purge_now;
 989                         if (!batadv_has_timed_out(backbone_gw->lasttime,
 990                                                   BATADV_BLA_BACKBONE_TIMEOUT))
 991                                 continue;
 992
 993                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 994                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
 995                                    backbone_gw->orig);
 996
 997 purge_now:
 998                         /* don't wait for the pending request anymore */
 999                         if (atomic_read(&backbone_gw->request_sent))
1000                                 atomic_dec(&bat_priv->bla.num_requests);
1001
1002                         batadv_bla_del_backbone_claims(backbone_gw);
1003
1004                         hlist_del_rcu(&backbone_gw->hash_entry);
1005                         batadv_backbone_gw_free_ref(backbone_gw);
1006                 }
1007                 spin_unlock_bh(list_lock);
1008         }
1009 }
1010
1011 /**
1012  * batadv_bla_purge_claims
1013  * @bat_priv: the bat priv with all the soft interface information
1014  * @primary_if: the selected primary interface, may be NULL if now is set
1015  * @now: whether the whole hash shall be wiped now
1016  *
1017  * Check when we heard last time from our own claims, and remove them in case of
1018  * a time out, or clean all claims if now is set
1019  */
1020 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
1021                                     struct batadv_hard_iface *primary_if,
1022                                     int now)
1023 {
1024         struct batadv_bla_claim *claim;
1025         struct hlist_head *head;
1026         struct batadv_hashtable *hash;
1027         int i;
1028
1029         hash = bat_priv->bla.claim_hash;
1030         if (!hash)
1031                 return;
1032
1033         for (i = 0; i < hash->size; i++) {
1034                 head = &hash->table[i];
1035
1036                 rcu_read_lock();
1037                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1038                         if (now)
1039                                 goto purge_now;
1040                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1041                                                 primary_if->net_dev->dev_addr))
1042                                 continue;
1043                         if (!batadv_has_timed_out(claim->lasttime,
1044                                                   BATADV_BLA_CLAIM_TIMEOUT))
1045                                 continue;
1046
1047                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1048                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1049                                    claim->addr, claim->vid);
1050
1051 purge_now:
1052                         batadv_handle_unclaim(bat_priv, primary_if,
1053                                               claim->backbone_gw->orig,
1054                                               claim->addr, claim->vid);
1055                 }
1056                 rcu_read_unlock();
1057         }
1058 }
1059
1060 /**
1061  * batadv_bla_update_orig_address
1062  * @bat_priv: the bat priv with all the soft interface information
1063  * @primary_if: the new selected primary_if
1064  * @oldif: the old primary interface, may be NULL
1065  *
1066  * Update the backbone gateways when the own orig address changes.
1067  */
1068 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1069                                     struct batadv_hard_iface *primary_if,
1070                                     struct batadv_hard_iface *oldif)
1071 {
1072         struct batadv_bla_backbone_gw *backbone_gw;
1073         struct hlist_head *head;
1074         struct batadv_hashtable *hash;
1075         __be16 group;
1076         int i;
1077
1078         /* reset bridge loop avoidance group id */
1079         group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1080         bat_priv->bla.claim_dest.group = group;
1081
1082         /* purge everything when bridge loop avoidance is turned off */
1083         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1084                 oldif = NULL;
1085
1086         if (!oldif) {
1087                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1088                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1089                 return;
1090         }
1091
1092         hash = bat_priv->bla.backbone_hash;
1093         if (!hash)
1094                 return;
1095
1096         for (i = 0; i < hash->size; i++) {
1097                 head = &hash->table[i];
1098
1099                 rcu_read_lock();
1100                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1101                         /* own orig still holds the old value. */
1102                         if (!batadv_compare_eth(backbone_gw->orig,
1103                                                 oldif->net_dev->dev_addr))
1104                                 continue;
1105
1106                         memcpy(backbone_gw->orig,
1107                                primary_if->net_dev->dev_addr, ETH_ALEN);
1108                         /* send an announce frame so others will ask for our
1109                          * claims and update their tables.
1110                          */
1111                         batadv_bla_send_announce(bat_priv, backbone_gw);
1112                 }
1113                 rcu_read_unlock();
1114         }
1115 }
1116
1117 /* periodic work to do:
1118  *  * purge structures when they are too old
1119  *  * send announcements
1120  */
1121 static void batadv_bla_periodic_work(struct work_struct *work)
1122 {
1123         struct delayed_work *delayed_work;
1124         struct batadv_priv *bat_priv;
1125         struct batadv_priv_bla *priv_bla;
1126         struct hlist_head *head;
1127         struct batadv_bla_backbone_gw *backbone_gw;
1128         struct batadv_hashtable *hash;
1129         struct batadv_hard_iface *primary_if;
1130         int i;
1131
1132         delayed_work = container_of(work, struct delayed_work, work);
1133         priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1134         bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1135         primary_if = batadv_primary_if_get_selected(bat_priv);
1136         if (!primary_if)
1137                 goto out;
1138
1139         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1140         batadv_bla_purge_backbone_gw(bat_priv, 0);
1141
1142         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1143                 goto out;
1144
1145         hash = bat_priv->bla.backbone_hash;
1146         if (!hash)
1147                 goto out;
1148
1149         for (i = 0; i < hash->size; i++) {
1150                 head = &hash->table[i];
1151
1152                 rcu_read_lock();
1153                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1154                         if (!batadv_compare_eth(backbone_gw->orig,
1155                                                 primary_if->net_dev->dev_addr))
1156                                 continue;
1157
1158                         backbone_gw->lasttime = jiffies;
1159
1160                         batadv_bla_send_announce(bat_priv, backbone_gw);
1161
1162                         /* request_sent is only set after creation to avoid
1163                          * problems when we are not yet known as backbone gw
1164                          * in the backbone.
1165                          *
1166                          * We can reset this now after we waited some periods
1167                          * to give bridge forward delays and bla group forming
1168                          * some grace time.
1169                          */
1170
1171                         if (atomic_read(&backbone_gw->request_sent) == 0)
1172                                 continue;
1173
1174                         if (!atomic_dec_and_test(&backbone_gw->wait_periods))
1175                                 continue;
1176
1177                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
1178                         atomic_set(&backbone_gw->request_sent, 0);
1179                 }
1180                 rcu_read_unlock();
1181         }
1182 out:
1183         if (primary_if)
1184                 batadv_hardif_free_ref(primary_if);
1185
1186         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1187                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1188 }
1189
1190 /* The hash for claim and backbone hash receive the same key because they
1191  * are getting initialized by hash_new with the same key. Reinitializing
1192  * them with to different keys to allow nested locking without generating
1193  * lockdep warnings
1194  */
1195 static struct lock_class_key batadv_claim_hash_lock_class_key;
1196 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1197
1198 /* initialize all bla structures */
1199 int batadv_bla_init(struct batadv_priv *bat_priv)
1200 {
1201         int i;
1202         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1203         struct batadv_hard_iface *primary_if;
1204         uint16_t crc;
1205         unsigned long entrytime;
1206
1207         spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1208
1209         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1210
1211         /* setting claim destination address */
1212         memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1213         bat_priv->bla.claim_dest.type = 0;
1214         primary_if = batadv_primary_if_get_selected(bat_priv);
1215         if (primary_if) {
1216                 crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1217                 bat_priv->bla.claim_dest.group = htons(crc);
1218                 batadv_hardif_free_ref(primary_if);
1219         } else {
1220                 bat_priv->bla.claim_dest.group = 0; /* will be set later */
1221         }
1222
1223         /* initialize the duplicate list */
1224         entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1225         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1226                 bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1227         bat_priv->bla.bcast_duplist_curr = 0;
1228
1229         if (bat_priv->bla.claim_hash)
1230                 return 0;
1231
1232         bat_priv->bla.claim_hash = batadv_hash_new(128);
1233         bat_priv->bla.backbone_hash = batadv_hash_new(32);
1234
1235         if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
1236                 return -ENOMEM;
1237
1238         batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1239                                    &batadv_claim_hash_lock_class_key);
1240         batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1241                                    &batadv_backbone_hash_lock_class_key);
1242
1243         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1244
1245         INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1246
1247         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1248                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1249         return 0;
1250 }
1251
1252 /**
1253  * batadv_bla_check_bcast_duplist
1254  * @bat_priv: the bat priv with all the soft interface information
1255  * @skb: contains the bcast_packet to be checked
1256  *
1257  * check if it is on our broadcast list. Another gateway might
1258  * have sent the same packet because it is connected to the same backbone,
1259  * so we have to remove this duplicate.
1260  *
1261  * This is performed by checking the CRC, which will tell us
1262  * with a good chance that it is the same packet. If it is furthermore
1263  * sent by another host, drop it. We allow equal packets from
1264  * the same host however as this might be intended.
1265  */
1266 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1267                                    struct sk_buff *skb)
1268 {
1269         int i, curr, ret = 0;
1270         __be32 crc;
1271         struct batadv_bcast_packet *bcast_packet;
1272         struct batadv_bcast_duplist_entry *entry;
1273
1274         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1275
1276         /* calculate the crc ... */
1277         crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
1278
1279         spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1280
1281         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1282                 curr = (bat_priv->bla.bcast_duplist_curr + i);
1283                 curr %= BATADV_DUPLIST_SIZE;
1284                 entry = &bat_priv->bla.bcast_duplist[curr];
1285
1286                 /* we can stop searching if the entry is too old ;
1287                  * later entries will be even older
1288                  */
1289                 if (batadv_has_timed_out(entry->entrytime,
1290                                          BATADV_DUPLIST_TIMEOUT))
1291                         break;
1292
1293                 if (entry->crc != crc)
1294                         continue;
1295
1296                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1297                         continue;
1298
1299                 /* this entry seems to match: same crc, not too old,
1300                  * and from another gw. therefore return 1 to forbid it.
1301                  */
1302                 ret = 1;
1303                 goto out;
1304         }
1305         /* not found, add a new entry (overwrite the oldest entry)
1306          * and allow it, its the first occurence.
1307          */
1308         curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1309         curr %= BATADV_DUPLIST_SIZE;
1310         entry = &bat_priv->bla.bcast_duplist[curr];
1311         entry->crc = crc;
1312         entry->entrytime = jiffies;
1313         memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
1314         bat_priv->bla.bcast_duplist_curr = curr;
1315
1316 out:
1317         spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1318
1319         return ret;
1320 }
1321
1322
1323
1324 /**
1325  * batadv_bla_is_backbone_gw_orig
1326  * @bat_priv: the bat priv with all the soft interface information
1327  * @orig: originator mac address
1328  * @vid: VLAN identifier
1329  *
1330  * Check if the originator is a gateway for the VLAN identified by vid.
1331  *
1332  * Returns true if orig is a backbone for this vid, false otherwise.
1333  */
1334 bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig,
1335                                     unsigned short vid)
1336 {
1337         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1338         struct hlist_head *head;
1339         struct batadv_bla_backbone_gw *backbone_gw;
1340         int i;
1341
1342         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1343                 return false;
1344
1345         if (!hash)
1346                 return false;
1347
1348         for (i = 0; i < hash->size; i++) {
1349                 head = &hash->table[i];
1350
1351                 rcu_read_lock();
1352                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1353                         if (batadv_compare_eth(backbone_gw->orig, orig) &&
1354                             backbone_gw->vid == vid) {
1355                                 rcu_read_unlock();
1356                                 return true;
1357                         }
1358                 }
1359                 rcu_read_unlock();
1360         }
1361
1362         return false;
1363 }
1364
1365
1366 /**
1367  * batadv_bla_is_backbone_gw
1368  * @skb: the frame to be checked
1369  * @orig_node: the orig_node of the frame
1370  * @hdr_size: maximum length of the frame
1371  *
1372  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1373  * if the orig_node is also a gateway on the soft interface, otherwise it
1374  * returns 0.
1375  */
1376 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1377                               struct batadv_orig_node *orig_node, int hdr_size)
1378 {
1379         struct batadv_bla_backbone_gw *backbone_gw;
1380         unsigned short vid;
1381
1382         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1383                 return 0;
1384
1385         /* first, find out the vid. */
1386         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1387                 return 0;
1388
1389         vid = batadv_get_vid(skb, hdr_size);
1390
1391         /* see if this originator is a backbone gw for this VLAN */
1392         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1393                                                 orig_node->orig, vid);
1394         if (!backbone_gw)
1395                 return 0;
1396
1397         batadv_backbone_gw_free_ref(backbone_gw);
1398         return 1;
1399 }
1400
1401 /* free all bla structures (for softinterface free or module unload) */
1402 void batadv_bla_free(struct batadv_priv *bat_priv)
1403 {
1404         struct batadv_hard_iface *primary_if;
1405
1406         cancel_delayed_work_sync(&bat_priv->bla.work);
1407         primary_if = batadv_primary_if_get_selected(bat_priv);
1408
1409         if (bat_priv->bla.claim_hash) {
1410                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1411                 batadv_hash_destroy(bat_priv->bla.claim_hash);
1412                 bat_priv->bla.claim_hash = NULL;
1413         }
1414         if (bat_priv->bla.backbone_hash) {
1415                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1416                 batadv_hash_destroy(bat_priv->bla.backbone_hash);
1417                 bat_priv->bla.backbone_hash = NULL;
1418         }
1419         if (primary_if)
1420                 batadv_hardif_free_ref(primary_if);
1421 }
1422
1423 /**
1424  * batadv_bla_rx
1425  * @bat_priv: the bat priv with all the soft interface information
1426  * @skb: the frame to be checked
1427  * @vid: the VLAN ID of the frame
1428  * @is_bcast: the packet came in a broadcast packet type.
1429  *
1430  * bla_rx avoidance checks if:
1431  *  * we have to race for a claim
1432  *  * if the frame is allowed on the LAN
1433  *
1434  * in these cases, the skb is further handled by this function and
1435  * returns 1, otherwise it returns 0 and the caller shall further
1436  * process the skb.
1437  */
1438 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1439                   unsigned short vid, bool is_bcast)
1440 {
1441         struct ethhdr *ethhdr;
1442         struct batadv_bla_claim search_claim, *claim = NULL;
1443         struct batadv_hard_iface *primary_if;
1444         int ret;
1445
1446         ethhdr = eth_hdr(skb);
1447
1448         primary_if = batadv_primary_if_get_selected(bat_priv);
1449         if (!primary_if)
1450                 goto handled;
1451
1452         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1453                 goto allow;
1454
1455
1456         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1457                 /* don't allow broadcasts while requests are in flight */
1458                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1459                         goto handled;
1460
1461         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1462         search_claim.vid = vid;
1463         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1464
1465         if (!claim) {
1466                 /* possible optimization: race for a claim */
1467                 /* No claim exists yet, claim it for us!
1468                  */
1469                 batadv_handle_claim(bat_priv, primary_if,
1470                                     primary_if->net_dev->dev_addr,
1471                                     ethhdr->h_source, vid);
1472                 goto allow;
1473         }
1474
1475         /* if it is our own claim ... */
1476         if (batadv_compare_eth(claim->backbone_gw->orig,
1477                                primary_if->net_dev->dev_addr)) {
1478                 /* ... allow it in any case */
1479                 claim->lasttime = jiffies;
1480                 goto allow;
1481         }
1482
1483         /* if it is a broadcast ... */
1484         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1485                 /* ... drop it. the responsible gateway is in charge.
1486                  *
1487                  * We need to check is_bcast because with the gateway
1488                  * feature, broadcasts (like DHCP requests) may be sent
1489                  * using a unicast packet type.
1490                  */
1491                 goto handled;
1492         } else {
1493                 /* seems the client considers us as its best gateway.
1494                  * send a claim and update the claim table
1495                  * immediately.
1496                  */
1497                 batadv_handle_claim(bat_priv, primary_if,
1498                                     primary_if->net_dev->dev_addr,
1499                                     ethhdr->h_source, vid);
1500                 goto allow;
1501         }
1502 allow:
1503         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1504         ret = 0;
1505         goto out;
1506
1507 handled:
1508         kfree_skb(skb);
1509         ret = 1;
1510
1511 out:
1512         if (primary_if)
1513                 batadv_hardif_free_ref(primary_if);
1514         if (claim)
1515                 batadv_claim_free_ref(claim);
1516         return ret;
1517 }
1518
1519 /**
1520  * batadv_bla_tx
1521  * @bat_priv: the bat priv with all the soft interface information
1522  * @skb: the frame to be checked
1523  * @vid: the VLAN ID of the frame
1524  *
1525  * bla_tx checks if:
1526  *  * a claim was received which has to be processed
1527  *  * the frame is allowed on the mesh
1528  *
1529  * in these cases, the skb is further handled by this function and
1530  * returns 1, otherwise it returns 0 and the caller shall further
1531  * process the skb.
1532  *
1533  * This call might reallocate skb data.
1534  */
1535 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1536                   unsigned short vid)
1537 {
1538         struct ethhdr *ethhdr;
1539         struct batadv_bla_claim search_claim, *claim = NULL;
1540         struct batadv_hard_iface *primary_if;
1541         int ret = 0;
1542
1543         primary_if = batadv_primary_if_get_selected(bat_priv);
1544         if (!primary_if)
1545                 goto out;
1546
1547         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1548                 goto allow;
1549
1550         /* in VLAN case, the mac header might not be set. */
1551         skb_reset_mac_header(skb);
1552
1553         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1554                 goto handled;
1555
1556         ethhdr = eth_hdr(skb);
1557
1558         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1559                 /* don't allow broadcasts while requests are in flight */
1560                 if (is_multicast_ether_addr(ethhdr->h_dest))
1561                         goto handled;
1562
1563         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1564         search_claim.vid = vid;
1565
1566         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1567
1568         /* if no claim exists, allow it. */
1569         if (!claim)
1570                 goto allow;
1571
1572         /* check if we are responsible. */
1573         if (batadv_compare_eth(claim->backbone_gw->orig,
1574                                primary_if->net_dev->dev_addr)) {
1575                 /* if yes, the client has roamed and we have
1576                  * to unclaim it.
1577                  */
1578                 batadv_handle_unclaim(bat_priv, primary_if,
1579                                       primary_if->net_dev->dev_addr,
1580                                       ethhdr->h_source, vid);
1581                 goto allow;
1582         }
1583
1584         /* check if it is a multicast/broadcast frame */
1585         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1586                 /* drop it. the responsible gateway has forwarded it into
1587                  * the backbone network.
1588                  */
1589                 goto handled;
1590         } else {
1591                 /* we must allow it. at least if we are
1592                  * responsible for the DESTINATION.
1593                  */
1594                 goto allow;
1595         }
1596 allow:
1597         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1598         ret = 0;
1599         goto out;
1600 handled:
1601         ret = 1;
1602 out:
1603         if (primary_if)
1604                 batadv_hardif_free_ref(primary_if);
1605         if (claim)
1606                 batadv_claim_free_ref(claim);
1607         return ret;
1608 }
1609
1610 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1611 {
1612         struct net_device *net_dev = (struct net_device *)seq->private;
1613         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1614         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
1615         struct batadv_bla_claim *claim;
1616         struct batadv_hard_iface *primary_if;
1617         struct hlist_head *head;
1618         uint32_t i;
1619         bool is_own;
1620         uint8_t *primary_addr;
1621
1622         primary_if = batadv_seq_print_text_primary_if_get(seq);
1623         if (!primary_if)
1624                 goto out;
1625
1626         primary_addr = primary_if->net_dev->dev_addr;
1627         seq_printf(seq,
1628                    "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
1629                    net_dev->name, primary_addr,
1630                    ntohs(bat_priv->bla.claim_dest.group));
1631         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-6s)\n",
1632                    "Client", "VID", "Originator", "CRC");
1633         for (i = 0; i < hash->size; i++) {
1634                 head = &hash->table[i];
1635
1636                 rcu_read_lock();
1637                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1638                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1639                                                     primary_addr);
1640                         seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n",
1641                                    claim->addr, BATADV_PRINT_VID(claim->vid),
1642                                    claim->backbone_gw->orig,
1643                                    (is_own ? 'x' : ' '),
1644                                    claim->backbone_gw->crc);
1645                 }
1646                 rcu_read_unlock();
1647         }
1648 out:
1649         if (primary_if)
1650                 batadv_hardif_free_ref(primary_if);
1651         return 0;
1652 }
1653
1654 int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
1655 {
1656         struct net_device *net_dev = (struct net_device *)seq->private;
1657         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1658         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1659         struct batadv_bla_backbone_gw *backbone_gw;
1660         struct batadv_hard_iface *primary_if;
1661         struct hlist_head *head;
1662         int secs, msecs;
1663         uint32_t i;
1664         bool is_own;
1665         uint8_t *primary_addr;
1666
1667         primary_if = batadv_seq_print_text_primary_if_get(seq);
1668         if (!primary_if)
1669                 goto out;
1670
1671         primary_addr = primary_if->net_dev->dev_addr;
1672         seq_printf(seq,
1673                    "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
1674                    net_dev->name, primary_addr,
1675                    ntohs(bat_priv->bla.claim_dest.group));
1676         seq_printf(seq, "   %-17s    %-5s %-9s (%-6s)\n",
1677                    "Originator", "VID", "last seen", "CRC");
1678         for (i = 0; i < hash->size; i++) {
1679                 head = &hash->table[i];
1680
1681                 rcu_read_lock();
1682                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1683                         msecs = jiffies_to_msecs(jiffies -
1684                                                  backbone_gw->lasttime);
1685                         secs = msecs / 1000;
1686                         msecs = msecs % 1000;
1687
1688                         is_own = batadv_compare_eth(backbone_gw->orig,
1689                                                     primary_addr);
1690                         if (is_own)
1691                                 continue;
1692
1693                         seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n",
1694                                    backbone_gw->orig,
1695                                    BATADV_PRINT_VID(backbone_gw->vid), secs,
1696                                    msecs, backbone_gw->crc);
1697                 }
1698                 rcu_read_unlock();
1699         }
1700 out:
1701         if (primary_if)
1702                 batadv_hardif_free_ref(primary_if);
1703         return 0;
1704 }