net/batman-adv/bridge_loop_avoidance.c

   1 /* Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
   2  *
   3  * Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "hash.h"
  22 #include "hard-interface.h"
  23 #include "originator.h"
  24 #include "bridge_loop_avoidance.h"
  25 #include "translation-table.h"
  26 #include "send.h"
  27
  28 #include <linux/etherdevice.h>
  29 #include <linux/crc16.h>
  30 #include <linux/if_arp.h>
  31 #include <net/arp.h>
  32 #include <linux/if_vlan.h>
  33
  34 static const uint8_t batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
  35
  36 static void batadv_bla_periodic_work(struct work_struct *work);
  37 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
  38                                      struct batadv_backbone_gw *backbone_gw);
  39
  40 /* return the index of the claim */
  41 static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
  42 {
  43         struct batadv_claim *claim = (struct batadv_claim *)data;
  44         uint32_t hash = 0;
  45
  46         hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  47         hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
  48
  49         hash += (hash << 3);
  50         hash ^= (hash >> 11);
  51         hash += (hash << 15);
  52
  53         return hash % size;
  54 }
  55
  56 /* return the index of the backbone gateway */
  57 static inline uint32_t batadv_choose_backbone_gw(const void *data,
  58                                                  uint32_t size)
  59 {
  60         struct batadv_claim *claim = (struct batadv_claim *)data;
  61         uint32_t hash = 0;
  62
  63         hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  64         hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
  65
  66         hash += (hash << 3);
  67         hash ^= (hash >> 11);
  68         hash += (hash << 15);
  69
  70         return hash % size;
  71 }
  72
  73
  74 /* compares address and vid of two backbone gws */
  75 static int batadv_compare_backbone_gw(const struct hlist_node *node,
  76                                       const void *data2)
  77 {
  78         const void *data1 = container_of(node, struct batadv_backbone_gw,
  79                                          hash_entry);
  80         const struct batadv_backbone_gw *gw1 = data1, *gw2 = data2;
  81
  82         if (!batadv_compare_eth(gw1->orig, gw2->orig))
  83                 return 0;
  84
  85         if (gw1->vid != gw2->vid)
  86                 return 0;
  87
  88         return 1;
  89 }
  90
  91 /* compares address and vid of two claims */
  92 static int batadv_compare_claim(const struct hlist_node *node,
  93                                 const void *data2)
  94 {
  95         const void *data1 = container_of(node, struct batadv_claim,
  96                                          hash_entry);
  97         const struct batadv_claim *cl1 = data1, *cl2 = data2;
  98
  99         if (!batadv_compare_eth(cl1->addr, cl2->addr))
 100                 return 0;
 101
 102         if (cl1->vid != cl2->vid)
 103                 return 0;
 104
 105         return 1;
 106 }
 107
 108 /* free a backbone gw */
 109 static void batadv_backbone_gw_free_ref(struct batadv_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_claim *claim;
 119
 120         claim = container_of(rcu, struct batadv_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_claim *claim)
 128 {
 129         if (atomic_dec_and_test(&claim->refcount))
 130                 call_rcu(&claim->rcu, batadv_claim_free_rcu);
 131 }
 132
 133 /* @bat_priv: the bat priv with all the soft interface information
 134  * @data: search data (may be local/static data)
 135  *
 136  * looks for a claim in the hash, and returns it if found
 137  * or NULL otherwise.
 138  */
 139 static struct batadv_claim *batadv_claim_hash_find(struct batadv_priv *bat_priv,
 140                                                    struct batadv_claim *data)
 141 {
 142         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
 143         struct hlist_head *head;
 144         struct hlist_node *node;
 145         struct batadv_claim *claim;
 146         struct batadv_claim *claim_tmp = NULL;
 147         int index;
 148
 149         if (!hash)
 150                 return NULL;
 151
 152         index = batadv_choose_claim(data, hash->size);
 153         head = &hash->table[index];
 154
 155         rcu_read_lock();
 156         hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 157                 if (!batadv_compare_claim(&claim->hash_entry, data))
 158                         continue;
 159
 160                 if (!atomic_inc_not_zero(&claim->refcount))
 161                         continue;
 162
 163                 claim_tmp = claim;
 164                 break;
 165         }
 166         rcu_read_unlock();
 167
 168         return claim_tmp;
 169 }
 170
 171 /**
 172  * batadv_backbone_hash_find - looks for a claim in the hash
 173  * @bat_priv: the bat priv with all the soft interface information
 174  * @addr: the address of the originator
 175  * @vid: the VLAN ID
 176  *
 177  * Returns claim if found or NULL otherwise.
 178  */
 179 static struct batadv_backbone_gw *
 180 batadv_backbone_hash_find(struct batadv_priv *bat_priv,
 181                           uint8_t *addr, short vid)
 182 {
 183         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
 184         struct hlist_head *head;
 185         struct hlist_node *node;
 186         struct batadv_backbone_gw search_entry, *backbone_gw;
 187         struct batadv_backbone_gw *backbone_gw_tmp = NULL;
 188         int index;
 189
 190         if (!hash)
 191                 return NULL;
 192
 193         memcpy(search_entry.orig, addr, ETH_ALEN);
 194         search_entry.vid = vid;
 195
 196         index = batadv_choose_backbone_gw(&search_entry, hash->size);
 197         head = &hash->table[index];
 198
 199         rcu_read_lock();
 200         hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
 201                 if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
 202                                                 &search_entry))
 203                         continue;
 204
 205                 if (!atomic_inc_not_zero(&backbone_gw->refcount))
 206                         continue;
 207
 208                 backbone_gw_tmp = backbone_gw;
 209                 break;
 210         }
 211         rcu_read_unlock();
 212
 213         return backbone_gw_tmp;
 214 }
 215
 216 /* delete all claims for a backbone */
 217 static void
 218 batadv_bla_del_backbone_claims(struct batadv_backbone_gw *backbone_gw)
 219 {
 220         struct batadv_hashtable *hash;
 221         struct hlist_node *node, *node_tmp;
 222         struct hlist_head *head;
 223         struct batadv_claim *claim;
 224         int i;
 225         spinlock_t *list_lock;  /* protects write access to the hash lists */
 226
 227         hash = backbone_gw->bat_priv->bla.claim_hash;
 228         if (!hash)
 229                 return;
 230
 231         for (i = 0; i < hash->size; i++) {
 232                 head = &hash->table[i];
 233                 list_lock = &hash->list_locks[i];
 234
 235                 spin_lock_bh(list_lock);
 236                 hlist_for_each_entry_safe(claim, node, node_tmp,
 237                                           head, hash_entry) {
 238                         if (claim->backbone_gw != backbone_gw)
 239                                 continue;
 240
 241                         batadv_claim_free_ref(claim);
 242                         hlist_del_rcu(node);
 243                 }
 244                 spin_unlock_bh(list_lock);
 245         }
 246
 247         /* all claims gone, intialize CRC */
 248         backbone_gw->crc = BATADV_BLA_CRC_INIT;
 249 }
 250
 251 /**
 252  * batadv_bla_send_claim - sends a claim frame according to the provided info
 253  * @bat_priv: the bat priv with all the soft interface information
 254  * @orig: the mac address to be announced within the claim
 255  * @vid: the VLAN ID
 256  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 257  */
 258 static void batadv_bla_send_claim(struct batadv_priv *bat_priv, uint8_t *mac,
 259                                   short vid, int claimtype)
 260 {
 261         struct sk_buff *skb;
 262         struct ethhdr *ethhdr;
 263         struct batadv_hard_iface *primary_if;
 264         struct net_device *soft_iface;
 265         uint8_t *hw_src;
 266         struct batadv_bla_claim_dst local_claim_dest;
 267         __be32 zeroip = 0;
 268
 269         primary_if = batadv_primary_if_get_selected(bat_priv);
 270         if (!primary_if)
 271                 return;
 272
 273         memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
 274                sizeof(local_claim_dest));
 275         local_claim_dest.type = claimtype;
 276
 277         soft_iface = primary_if->soft_iface;
 278
 279         skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
 280                          /* IP DST: 0.0.0.0 */
 281                          zeroip,
 282                          primary_if->soft_iface,
 283                          /* IP SRC: 0.0.0.0 */
 284                          zeroip,
 285                          /* Ethernet DST: Broadcast */
 286                          NULL,
 287                          /* Ethernet SRC/HW SRC:  originator mac */
 288                          primary_if->net_dev->dev_addr,
 289                          /* HW DST: FF:43:05:XX:YY:YY
 290                           * with XX   = claim type
 291                           * and YY:YY = group id
 292                           */
 293                          (uint8_t *)&local_claim_dest);
 294
 295         if (!skb)
 296                 goto out;
 297
 298         ethhdr = (struct ethhdr *)skb->data;
 299         hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
 300
 301         /* now we pretend that the client would have sent this ... */
 302         switch (claimtype) {
 303         case BATADV_CLAIM_TYPE_CLAIM:
 304                 /* normal claim frame
 305                  * set Ethernet SRC to the clients mac
 306                  */
 307                 memcpy(ethhdr->h_source, mac, ETH_ALEN);
 308                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 309                            "bla_send_claim(): CLAIM %pM on vid %d\n", mac, vid);
 310                 break;
 311         case BATADV_CLAIM_TYPE_UNCLAIM:
 312                 /* unclaim frame
 313                  * set HW SRC to the clients mac
 314                  */
 315                 memcpy(hw_src, mac, ETH_ALEN);
 316                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 317                            "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
 318                            vid);
 319                 break;
 320         case BATADV_CLAIM_TYPE_ANNOUNCE:
 321                 /* announcement frame
 322                  * set HW SRC to the special mac containg the crc
 323                  */
 324                 memcpy(hw_src, mac, ETH_ALEN);
 325                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 326                            "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
 327                            ethhdr->h_source, vid);
 328                 break;
 329         case BATADV_CLAIM_TYPE_REQUEST:
 330                 /* request frame
 331                  * set HW SRC and header destination to the receiving backbone
 332                  * gws mac
 333                  */
 334                 memcpy(hw_src, mac, ETH_ALEN);
 335                 memcpy(ethhdr->h_dest, mac, ETH_ALEN);
 336                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 337                            "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
 338                            ethhdr->h_source, ethhdr->h_dest, vid);
 339                 break;
 340         }
 341
 342         if (vid != -1)
 343                 skb = vlan_insert_tag(skb, vid);
 344
 345         skb_reset_mac_header(skb);
 346         skb->protocol = eth_type_trans(skb, soft_iface);
 347         batadv_inc_counter(bat_priv, BATADV_CNT_RX);
 348         batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
 349                            skb->len + ETH_HLEN);
 350         soft_iface->last_rx = jiffies;
 351
 352         netif_rx(skb);
 353 out:
 354         if (primary_if)
 355                 batadv_hardif_free_ref(primary_if);
 356 }
 357
 358 /**
 359  * batadv_bla_get_backbone_gw
 360  * @bat_priv: the bat priv with all the soft interface information
 361  * @orig: the mac address of the originator
 362  * @vid: the VLAN ID
 363  *
 364  * searches for the backbone gw or creates a new one if it could not
 365  * be found.
 366  */
 367 static struct batadv_backbone_gw *
 368 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 369                            short vid, bool own_backbone)
 370 {
 371         struct batadv_backbone_gw *entry;
 372         struct batadv_orig_node *orig_node;
 373         int hash_added;
 374
 375         entry = batadv_backbone_hash_find(bat_priv, orig, vid);
 376
 377         if (entry)
 378                 return entry;
 379
 380         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 381                    "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 382                    orig, vid);
 383
 384         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 385         if (!entry)
 386                 return NULL;
 387
 388         entry->vid = vid;
 389         entry->lasttime = jiffies;
 390         entry->crc = BATADV_BLA_CRC_INIT;
 391         entry->bat_priv = bat_priv;
 392         atomic_set(&entry->request_sent, 0);
 393         atomic_set(&entry->wait_periods, 0);
 394         memcpy(entry->orig, orig, ETH_ALEN);
 395
 396         /* one for the hash, one for returning */
 397         atomic_set(&entry->refcount, 2);
 398
 399         hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
 400                                      batadv_compare_backbone_gw,
 401                                      batadv_choose_backbone_gw, entry,
 402                                      &entry->hash_entry);
 403
 404         if (unlikely(hash_added != 0)) {
 405                 /* hash failed, free the structure */
 406                 kfree(entry);
 407                 return NULL;
 408         }
 409
 410         /* this is a gateway now, remove any tt entries */
 411         orig_node = batadv_orig_hash_find(bat_priv, orig);
 412         if (orig_node) {
 413                 batadv_tt_global_del_orig(bat_priv, orig_node,
 414                                           "became a backbone gateway");
 415                 batadv_orig_node_free_ref(orig_node);
 416         }
 417
 418         if (own_backbone) {
 419                 batadv_bla_send_announce(bat_priv, entry);
 420
 421                 /* this will be decreased in the worker thread */
 422                 atomic_inc(&entry->request_sent);
 423                 atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
 424                 atomic_inc(&bat_priv->bla.num_requests);
 425         }
 426
 427         return entry;
 428 }
 429
 430 /* update or add the own backbone gw to make sure we announce
 431  * where we receive other backbone gws
 432  */
 433 static void
 434 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 435                                   struct batadv_hard_iface *primary_if,
 436                                   short vid)
 437 {
 438         struct batadv_backbone_gw *backbone_gw;
 439
 440         backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 441                                                  primary_if->net_dev->dev_addr,
 442                                                  vid, true);
 443         if (unlikely(!backbone_gw))
 444                 return;
 445
 446         backbone_gw->lasttime = jiffies;
 447         batadv_backbone_gw_free_ref(backbone_gw);
 448 }
 449
 450 /* @bat_priv: the bat priv with all the soft interface information
 451  * @vid: the vid where the request came on
 452  *
 453  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 454  * to allow the requester another check if the CRC is correct now.
 455  */
 456 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
 457                                       struct batadv_hard_iface *primary_if,
 458                                       short vid)
 459 {
 460         struct hlist_node *node;
 461         struct hlist_head *head;
 462         struct batadv_hashtable *hash;
 463         struct batadv_claim *claim;
 464         struct batadv_backbone_gw *backbone_gw;
 465         int i;
 466
 467         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 468                    "bla_answer_request(): received a claim request, send all of our own claims again\n");
 469
 470         backbone_gw = batadv_backbone_hash_find(bat_priv,
 471                                                 primary_if->net_dev->dev_addr,
 472                                                 vid);
 473         if (!backbone_gw)
 474                 return;
 475
 476         hash = bat_priv->bla.claim_hash;
 477         for (i = 0; i < hash->size; i++) {
 478                 head = &hash->table[i];
 479
 480                 rcu_read_lock();
 481                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
 482                         /* only own claims are interesting */
 483                         if (claim->backbone_gw != backbone_gw)
 484                                 continue;
 485
 486                         batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
 487                                               BATADV_CLAIM_TYPE_CLAIM);
 488                 }
 489                 rcu_read_unlock();
 490         }
 491
 492         /* finally, send an announcement frame */
 493         batadv_bla_send_announce(bat_priv, backbone_gw);
 494         batadv_backbone_gw_free_ref(backbone_gw);
 495 }
 496
 497 /* @backbone_gw: the backbone gateway from whom we are out of sync
 498  *
 499  * When the crc is wrong, ask the backbone gateway for a full table update.
 500  * After the request, it will repeat all of his own claims and finally
 501  * send an announcement claim with which we can check again.
 502  */
 503 static void batadv_bla_send_request(struct batadv_backbone_gw *backbone_gw)
 504 {
 505         /* first, remove all old entries */
 506         batadv_bla_del_backbone_claims(backbone_gw);
 507
 508         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 509                    "Sending REQUEST to %pM\n", backbone_gw->orig);
 510
 511         /* send request */
 512         batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 513                               backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
 514
 515         /* no local broadcasts should be sent or received, for now. */
 516         if (!atomic_read(&backbone_gw->request_sent)) {
 517                 atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
 518                 atomic_set(&backbone_gw->request_sent, 1);
 519         }
 520 }
 521
 522 /* @bat_priv: the bat priv with all the soft interface information
 523  * @backbone_gw: our backbone gateway which should be announced
 524  *
 525  * This function sends an announcement. It is called from multiple
 526  * places.
 527  */
 528 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 529                                      struct batadv_backbone_gw *backbone_gw)
 530 {
 531         uint8_t mac[ETH_ALEN];
 532         __be16 crc;
 533
 534         memcpy(mac, batadv_announce_mac, 4);
 535         crc = htons(backbone_gw->crc);
 536         memcpy(&mac[4], &crc, 2);
 537
 538         batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
 539                               BATADV_CLAIM_TYPE_ANNOUNCE);
 540 }
 541
 542 /**
 543  * batadv_bla_add_claim - Adds a claim in the claim hash
 544  * @bat_priv: the bat priv with all the soft interface information
 545  * @mac: the mac address of the claim
 546  * @vid: the VLAN ID of the frame
 547  * @backbone_gw: the backbone gateway which claims it
 548  */
 549 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
 550                                  const uint8_t *mac, const short vid,
 551                                  struct batadv_backbone_gw *backbone_gw)
 552 {
 553         struct batadv_claim *claim;
 554         struct batadv_claim search_claim;
 555         int hash_added;
 556
 557         memcpy(search_claim.addr, mac, ETH_ALEN);
 558         search_claim.vid = vid;
 559         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 560
 561         /* create a new claim entry if it does not exist yet. */
 562         if (!claim) {
 563                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 564                 if (!claim)
 565                         return;
 566
 567                 memcpy(claim->addr, mac, ETH_ALEN);
 568                 claim->vid = vid;
 569                 claim->lasttime = jiffies;
 570                 claim->backbone_gw = backbone_gw;
 571
 572                 atomic_set(&claim->refcount, 2);
 573                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 574                            "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 575                            mac, vid);
 576                 hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
 577                                              batadv_compare_claim,
 578                                              batadv_choose_claim, claim,
 579                                              &claim->hash_entry);
 580
 581                 if (unlikely(hash_added != 0)) {
 582                         /* only local changes happened. */
 583                         kfree(claim);
 584                         return;
 585                 }
 586         } else {
 587                 claim->lasttime = jiffies;
 588                 if (claim->backbone_gw == backbone_gw)
 589                         /* no need to register a new backbone */
 590                         goto claim_free_ref;
 591
 592                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 593                            "bla_add_claim(): changing ownership for %pM, vid %d\n",
 594                            mac, vid);
 595
 596                 claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 597                 batadv_backbone_gw_free_ref(claim->backbone_gw);
 598         }
 599         /* set (new) backbone gw */
 600         atomic_inc(&backbone_gw->refcount);
 601         claim->backbone_gw = backbone_gw;
 602
 603         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 604         backbone_gw->lasttime = jiffies;
 605
 606 claim_free_ref:
 607         batadv_claim_free_ref(claim);
 608 }
 609
 610 /* Delete a claim from the claim hash which has the
 611  * given mac address and vid.
 612  */
 613 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
 614                                  const uint8_t *mac, const short vid)
 615 {
 616         struct batadv_claim search_claim, *claim;
 617
 618         memcpy(search_claim.addr, mac, ETH_ALEN);
 619         search_claim.vid = vid;
 620         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 621         if (!claim)
 622                 return;
 623
 624         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
 625                    mac, vid);
 626
 627         batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
 628                            batadv_choose_claim, claim);
 629         batadv_claim_free_ref(claim); /* reference from the hash is gone */
 630
 631         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 632
 633         /* don't need the reference from hash_find() anymore */
 634         batadv_claim_free_ref(claim);
 635 }
 636
 637 /* check for ANNOUNCE frame, return 1 if handled */
 638 static int batadv_handle_announce(struct batadv_priv *bat_priv,
 639                                   uint8_t *an_addr, uint8_t *backbone_addr,
 640                                   short vid)
 641 {
 642         struct batadv_backbone_gw *backbone_gw;
 643         uint16_t crc;
 644
 645         if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 646                 return 0;
 647
 648         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 649                                                  false);
 650
 651         if (unlikely(!backbone_gw))
 652                 return 1;
 653
 654
 655         /* handle as ANNOUNCE frame */
 656         backbone_gw->lasttime = jiffies;
 657         crc = ntohs(*((__be16 *)(&an_addr[4])));
 658
 659         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 660                    "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
 661                    vid, backbone_gw->orig, crc);
 662
 663         if (backbone_gw->crc != crc) {
 664                 batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 665                            "handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
 666                            backbone_gw->orig, backbone_gw->vid,
 667                            backbone_gw->crc, crc);
 668
 669                 batadv_bla_send_request(backbone_gw);
 670         } else {
 671                 /* if we have sent a request and the crc was OK,
 672                  * we can allow traffic again.
 673                  */
 674                 if (atomic_read(&backbone_gw->request_sent)) {
 675                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
 676                         atomic_set(&backbone_gw->request_sent, 0);
 677                 }
 678         }
 679
 680         batadv_backbone_gw_free_ref(backbone_gw);
 681         return 1;
 682 }
 683
 684 /* check for REQUEST frame, return 1 if handled */
 685 static int batadv_handle_request(struct batadv_priv *bat_priv,
 686                                  struct batadv_hard_iface *primary_if,
 687                                  uint8_t *backbone_addr,
 688                                  struct ethhdr *ethhdr, short vid)
 689 {
 690         /* check for REQUEST frame */
 691         if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
 692                 return 0;
 693
 694         /* sanity check, this should not happen on a normal switch,
 695          * we ignore it in this case.
 696          */
 697         if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 698                 return 1;
 699
 700         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 701                    "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 702                    vid, ethhdr->h_source);
 703
 704         batadv_bla_answer_request(bat_priv, primary_if, vid);
 705         return 1;
 706 }
 707
 708 /* check for UNCLAIM frame, return 1 if handled */
 709 static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
 710                                  struct batadv_hard_iface *primary_if,
 711                                  uint8_t *backbone_addr,
 712                                  uint8_t *claim_addr, short vid)
 713 {
 714         struct batadv_backbone_gw *backbone_gw;
 715
 716         /* unclaim in any case if it is our own */
 717         if (primary_if && batadv_compare_eth(backbone_addr,
 718                                              primary_if->net_dev->dev_addr))
 719                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 720                                       BATADV_CLAIM_TYPE_UNCLAIM);
 721
 722         backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
 723
 724         if (!backbone_gw)
 725                 return 1;
 726
 727         /* this must be an UNCLAIM frame */
 728         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 729                    "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 730                    claim_addr, vid, backbone_gw->orig);
 731
 732         batadv_bla_del_claim(bat_priv, claim_addr, vid);
 733         batadv_backbone_gw_free_ref(backbone_gw);
 734         return 1;
 735 }
 736
 737 /* check for CLAIM frame, return 1 if handled */
 738 static int batadv_handle_claim(struct batadv_priv *bat_priv,
 739                                struct batadv_hard_iface *primary_if,
 740                                uint8_t *backbone_addr, uint8_t *claim_addr,
 741                                short vid)
 742 {
 743         struct batadv_backbone_gw *backbone_gw;
 744
 745         /* register the gateway if not yet available, and add the claim. */
 746
 747         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 748                                                  false);
 749
 750         if (unlikely(!backbone_gw))
 751                 return 1;
 752
 753         /* this must be a CLAIM frame */
 754         batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 755         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 756                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 757                                       BATADV_CLAIM_TYPE_CLAIM);
 758
 759         /* TODO: we could call something like tt_local_del() here. */
 760
 761         batadv_backbone_gw_free_ref(backbone_gw);
 762         return 1;
 763 }
 764
 765 /**
 766  * batadv_check_claim_group
 767  * @bat_priv: the bat priv with all the soft interface information
 768  * @hw_src: the Hardware source in the ARP Header
 769  * @hw_dst: the Hardware destination in the ARP Header
 770  * @ethhdr: pointer to the Ethernet header of the claim frame
 771  *
 772  * checks if it is a claim packet and if its on the same group.
 773  * This function also applies the group ID of the sender
 774  * if it is in the same mesh.
 775  *
 776  * returns:
 777  *      2  - if it is a claim packet and on the same group
 778  *      1  - if is a claim packet from another group
 779  *      0  - if it is not a claim packet
 780  */
 781 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 782                                     struct batadv_hard_iface *primary_if,
 783                                     uint8_t *hw_src, uint8_t *hw_dst,
 784                                     struct ethhdr *ethhdr)
 785 {
 786         uint8_t *backbone_addr;
 787         struct batadv_orig_node *orig_node;
 788         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 789
 790         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 791         bla_dst_own = &bat_priv->bla.claim_dest;
 792
 793         /* check if it is a claim packet in general */
 794         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 795                    sizeof(bla_dst->magic)) != 0)
 796                 return 0;
 797
 798         /* if announcement packet, use the source,
 799          * otherwise assume it is in the hw_src
 800          */
 801         switch (bla_dst->type) {
 802         case BATADV_CLAIM_TYPE_CLAIM:
 803                 backbone_addr = hw_src;
 804                 break;
 805         case BATADV_CLAIM_TYPE_REQUEST:
 806         case BATADV_CLAIM_TYPE_ANNOUNCE:
 807         case BATADV_CLAIM_TYPE_UNCLAIM:
 808                 backbone_addr = ethhdr->h_source;
 809                 break;
 810         default:
 811                 return 0;
 812         }
 813
 814         /* don't accept claim frames from ourselves */
 815         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 816                 return 0;
 817
 818         /* if its already the same group, it is fine. */
 819         if (bla_dst->group == bla_dst_own->group)
 820                 return 2;
 821
 822         /* lets see if this originator is in our mesh */
 823         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 824
 825         /* dont accept claims from gateways which are not in
 826          * the same mesh or group.
 827          */
 828         if (!orig_node)
 829                 return 1;
 830
 831         /* if our mesh friends mac is bigger, use it for ourselves. */
 832         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 833                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 834                            "taking other backbones claim group: %#.4x\n",
 835                            ntohs(bla_dst->group));
 836                 bla_dst_own->group = bla_dst->group;
 837         }
 838
 839         batadv_orig_node_free_ref(orig_node);
 840
 841         return 2;
 842 }
 843
 844
 845 /* @bat_priv: the bat priv with all the soft interface information
 846  * @skb: the frame to be checked
 847  *
 848  * Check if this is a claim frame, and process it accordingly.
 849  *
 850  * returns 1 if it was a claim frame, otherwise return 0 to
 851  * tell the callee that it can use the frame on its own.
 852  */
 853 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 854                                     struct batadv_hard_iface *primary_if,
 855                                     struct sk_buff *skb)
 856 {
 857         struct ethhdr *ethhdr;
 858         struct vlan_ethhdr *vhdr;
 859         struct arphdr *arphdr;
 860         uint8_t *hw_src, *hw_dst;
 861         struct batadv_bla_claim_dst *bla_dst;
 862         uint16_t proto;
 863         int headlen;
 864         short vid = -1;
 865         int ret;
 866
 867         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 868
 869         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 870                 vhdr = (struct vlan_ethhdr *)ethhdr;
 871                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
 872                 proto = ntohs(vhdr->h_vlan_encapsulated_proto);
 873                 headlen = sizeof(*vhdr);
 874         } else {
 875                 proto = ntohs(ethhdr->h_proto);
 876                 headlen = ETH_HLEN;
 877         }
 878
 879         if (proto != ETH_P_ARP)
 880                 return 0; /* not a claim frame */
 881
 882         /* this must be a ARP frame. check if it is a claim. */
 883
 884         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 885                 return 0;
 886
 887         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 888         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 889         arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);
 890
 891         /* Check whether the ARP frame carries a valid
 892          * IP information
 893          */
 894         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 895                 return 0;
 896         if (arphdr->ar_pro != htons(ETH_P_IP))
 897                 return 0;
 898         if (arphdr->ar_hln != ETH_ALEN)
 899                 return 0;
 900         if (arphdr->ar_pln != 4)
 901                 return 0;
 902
 903         hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 904         hw_dst = hw_src + ETH_ALEN + 4;
 905         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 906
 907         /* check if it is a claim frame. */
 908         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 909                                        ethhdr);
 910         if (ret == 1)
 911                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 912                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 913                            ethhdr->h_source, vid, hw_src, hw_dst);
 914
 915         if (ret < 2)
 916                 return ret;
 917
 918         /* become a backbone gw ourselves on this vlan if not happened yet */
 919         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 920
 921         /* check for the different types of claim frames ... */
 922         switch (bla_dst->type) {
 923         case BATADV_CLAIM_TYPE_CLAIM:
 924                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 925                                         ethhdr->h_source, vid))
 926                         return 1;
 927                 break;
 928         case BATADV_CLAIM_TYPE_UNCLAIM:
 929                 if (batadv_handle_unclaim(bat_priv, primary_if,
 930                                           ethhdr->h_source, hw_src, vid))
 931                         return 1;
 932                 break;
 933
 934         case BATADV_CLAIM_TYPE_ANNOUNCE:
 935                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
 936                                            vid))
 937                         return 1;
 938                 break;
 939         case BATADV_CLAIM_TYPE_REQUEST:
 940                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
 941                                           vid))
 942                         return 1;
 943                 break;
 944         }
 945
 946         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 947                    "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",
 948                    ethhdr->h_source, vid, hw_src, hw_dst);
 949         return 1;
 950 }
 951
 952 /* Check when we last heard from other nodes, and remove them in case of
 953  * a time out, or clean all backbone gws if now is set.
 954  */
 955 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
 956 {
 957         struct batadv_backbone_gw *backbone_gw;
 958         struct hlist_node *node, *node_tmp;
 959         struct hlist_head *head;
 960         struct batadv_hashtable *hash;
 961         spinlock_t *list_lock;  /* protects write access to the hash lists */
 962         int i;
 963
 964         hash = bat_priv->bla.backbone_hash;
 965         if (!hash)
 966                 return;
 967
 968         for (i = 0; i < hash->size; i++) {
 969                 head = &hash->table[i];
 970                 list_lock = &hash->list_locks[i];
 971
 972                 spin_lock_bh(list_lock);
 973                 hlist_for_each_entry_safe(backbone_gw, node, node_tmp,
 974                                           head, hash_entry) {
 975                         if (now)
 976                                 goto purge_now;
 977                         if (!batadv_has_timed_out(backbone_gw->lasttime,
 978                                                   BATADV_BLA_BACKBONE_TIMEOUT))
 979                                 continue;
 980
 981                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 982                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
 983                                    backbone_gw->orig);
 984
 985 purge_now:
 986                         /* don't wait for the pending request anymore */
 987                         if (atomic_read(&backbone_gw->request_sent))
 988                                 atomic_dec(&bat_priv->bla.num_requests);
 989
 990                         batadv_bla_del_backbone_claims(backbone_gw);
 991
 992                         hlist_del_rcu(node);
 993                         batadv_backbone_gw_free_ref(backbone_gw);
 994                 }
 995                 spin_unlock_bh(list_lock);
 996         }
 997 }
 998
 999 /**
1000  * batadv_bla_purge_claims
1001  * @bat_priv: the bat priv with all the soft interface information
1002  * @primary_if: the selected primary interface, may be NULL if now is set
1003  * @now: whether the whole hash shall be wiped now
1004  *
1005  * Check when we heard last time from our own claims, and remove them in case of
1006  * a time out, or clean all claims if now is set
1007  */
1008 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
1009                                     struct batadv_hard_iface *primary_if,
1010                                     int now)
1011 {
1012         struct batadv_claim *claim;
1013         struct hlist_node *node;
1014         struct hlist_head *head;
1015         struct batadv_hashtable *hash;
1016         int i;
1017
1018         hash = bat_priv->bla.claim_hash;
1019         if (!hash)
1020                 return;
1021
1022         for (i = 0; i < hash->size; i++) {
1023                 head = &hash->table[i];
1024
1025                 rcu_read_lock();
1026                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1027                         if (now)
1028                                 goto purge_now;
1029                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1030                                                 primary_if->net_dev->dev_addr))
1031                                 continue;
1032                         if (!batadv_has_timed_out(claim->lasttime,
1033                                                   BATADV_BLA_CLAIM_TIMEOUT))
1034                                 continue;
1035
1036                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1037                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1038                                    claim->addr, claim->vid);
1039
1040 purge_now:
1041                         batadv_handle_unclaim(bat_priv, primary_if,
1042                                               claim->backbone_gw->orig,
1043                                               claim->addr, claim->vid);
1044                 }
1045                 rcu_read_unlock();
1046         }
1047 }
1048
1049 /**
1050  * batadv_bla_update_orig_address
1051  * @bat_priv: the bat priv with all the soft interface information
1052  * @primary_if: the new selected primary_if
1053  * @oldif: the old primary interface, may be NULL
1054  *
1055  * Update the backbone gateways when the own orig address changes.
1056  */
1057 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1058                                     struct batadv_hard_iface *primary_if,
1059                                     struct batadv_hard_iface *oldif)
1060 {
1061         struct batadv_backbone_gw *backbone_gw;
1062         struct hlist_node *node;
1063         struct hlist_head *head;
1064         struct batadv_hashtable *hash;
1065         __be16 group;
1066         int i;
1067
1068         /* reset bridge loop avoidance group id */
1069         group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1070         bat_priv->bla.claim_dest.group = group;
1071
1072         if (!oldif) {
1073                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1074                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1075                 return;
1076         }
1077
1078         hash = bat_priv->bla.backbone_hash;
1079         if (!hash)
1080                 return;
1081
1082         for (i = 0; i < hash->size; i++) {
1083                 head = &hash->table[i];
1084
1085                 rcu_read_lock();
1086                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1087                         /* own orig still holds the old value. */
1088                         if (!batadv_compare_eth(backbone_gw->orig,
1089                                                 oldif->net_dev->dev_addr))
1090                                 continue;
1091
1092                         memcpy(backbone_gw->orig,
1093                                primary_if->net_dev->dev_addr, ETH_ALEN);
1094                         /* send an announce frame so others will ask for our
1095                          * claims and update their tables.
1096                          */
1097                         batadv_bla_send_announce(bat_priv, backbone_gw);
1098                 }
1099                 rcu_read_unlock();
1100         }
1101 }
1102
1103
1104
1105 /* (re)start the timer */
1106 static void batadv_bla_start_timer(struct batadv_priv *bat_priv)
1107 {
1108         INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1109         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1110                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1111 }
1112
1113 /* periodic work to do:
1114  *  * purge structures when they are too old
1115  *  * send announcements
1116  */
1117 static void batadv_bla_periodic_work(struct work_struct *work)
1118 {
1119         struct delayed_work *delayed_work;
1120         struct batadv_priv *bat_priv;
1121         struct batadv_priv_bla *priv_bla;
1122         struct hlist_node *node;
1123         struct hlist_head *head;
1124         struct batadv_backbone_gw *backbone_gw;
1125         struct batadv_hashtable *hash;
1126         struct batadv_hard_iface *primary_if;
1127         int i;
1128
1129         delayed_work = container_of(work, struct delayed_work, work);
1130         priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1131         bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1132         primary_if = batadv_primary_if_get_selected(bat_priv);
1133         if (!primary_if)
1134                 goto out;
1135
1136         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1137         batadv_bla_purge_backbone_gw(bat_priv, 0);
1138
1139         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1140                 goto out;
1141
1142         hash = bat_priv->bla.backbone_hash;
1143         if (!hash)
1144                 goto out;
1145
1146         for (i = 0; i < hash->size; i++) {
1147                 head = &hash->table[i];
1148
1149                 rcu_read_lock();
1150                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1151                         if (!batadv_compare_eth(backbone_gw->orig,
1152                                                 primary_if->net_dev->dev_addr))
1153                                 continue;
1154
1155                         backbone_gw->lasttime = jiffies;
1156
1157                         batadv_bla_send_announce(bat_priv, backbone_gw);
1158
1159                         /* request_sent is only set after creation to avoid
1160                          * problems when we are not yet known as backbone gw
1161                          * in the backbone.
1162                          *
1163                          * We can reset this now after we waited some periods
1164                          * to give bridge forward delays and bla group forming
1165                          * some grace time.
1166                          */
1167
1168                         if (atomic_read(&backbone_gw->request_sent) == 0)
1169                                 continue;
1170
1171                         if (!atomic_dec_and_test(&backbone_gw->wait_periods))
1172                                 continue;
1173
1174                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
1175                         atomic_set(&backbone_gw->request_sent, 0);
1176                 }
1177                 rcu_read_unlock();
1178         }
1179 out:
1180         if (primary_if)
1181                 batadv_hardif_free_ref(primary_if);
1182
1183         batadv_bla_start_timer(bat_priv);
1184 }
1185
1186 /* The hash for claim and backbone hash receive the same key because they
1187  * are getting initialized by hash_new with the same key. Reinitializing
1188  * them with to different keys to allow nested locking without generating
1189  * lockdep warnings
1190  */
1191 static struct lock_class_key batadv_claim_hash_lock_class_key;
1192 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1193
1194 /* initialize all bla structures */
1195 int batadv_bla_init(struct batadv_priv *bat_priv)
1196 {
1197         int i;
1198         uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1199         struct batadv_hard_iface *primary_if;
1200         uint16_t crc;
1201         unsigned long entrytime;
1202
1203         spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1204
1205         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1206
1207         /* setting claim destination address */
1208         memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1209         bat_priv->bla.claim_dest.type = 0;
1210         primary_if = batadv_primary_if_get_selected(bat_priv);
1211         if (primary_if) {
1212                 crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1213                 bat_priv->bla.claim_dest.group = htons(crc);
1214                 batadv_hardif_free_ref(primary_if);
1215         } else {
1216                 bat_priv->bla.claim_dest.group = 0; /* will be set later */
1217         }
1218
1219         /* initialize the duplicate list */
1220         entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1221         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1222                 bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1223         bat_priv->bla.bcast_duplist_curr = 0;
1224
1225         if (bat_priv->bla.claim_hash)
1226                 return 0;
1227
1228         bat_priv->bla.claim_hash = batadv_hash_new(128);
1229         bat_priv->bla.backbone_hash = batadv_hash_new(32);
1230
1231         if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
1232                 return -ENOMEM;
1233
1234         batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1235                                    &batadv_claim_hash_lock_class_key);
1236         batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1237                                    &batadv_backbone_hash_lock_class_key);
1238
1239         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1240
1241         batadv_bla_start_timer(bat_priv);
1242         return 0;
1243 }
1244
1245 /**
1246  * batadv_bla_check_bcast_duplist
1247  * @bat_priv: the bat priv with all the soft interface information
1248  * @skb: contains the bcast_packet to be checked
1249  *
1250  * check if it is on our broadcast list. Another gateway might
1251  * have sent the same packet because it is connected to the same backbone,
1252  * so we have to remove this duplicate.
1253  *
1254  * This is performed by checking the CRC, which will tell us
1255  * with a good chance that it is the same packet. If it is furthermore
1256  * sent by another host, drop it. We allow equal packets from
1257  * the same host however as this might be intended.
1258  */
1259 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1260                                    struct sk_buff *skb)
1261 {
1262         int i, curr, ret = 0;
1263         __be32 crc;
1264         struct batadv_bcast_packet *bcast_packet;
1265         struct batadv_bcast_duplist_entry *entry;
1266
1267         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1268
1269         /* calculate the crc ... */
1270         crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
1271
1272         spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1273
1274         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1275                 curr = (bat_priv->bla.bcast_duplist_curr + i);
1276                 curr %= BATADV_DUPLIST_SIZE;
1277                 entry = &bat_priv->bla.bcast_duplist[curr];
1278
1279                 /* we can stop searching if the entry is too old ;
1280                  * later entries will be even older
1281                  */
1282                 if (batadv_has_timed_out(entry->entrytime,
1283                                          BATADV_DUPLIST_TIMEOUT))
1284                         break;
1285
1286                 if (entry->crc != crc)
1287                         continue;
1288
1289                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1290                         continue;
1291
1292                 /* this entry seems to match: same crc, not too old,
1293                  * and from another gw. therefore return 1 to forbid it.
1294                  */
1295                 ret = 1;
1296                 goto out;
1297         }
1298         /* not found, add a new entry (overwrite the oldest entry)
1299          * and allow it, its the first occurence.
1300          */
1301         curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1302         curr %= BATADV_DUPLIST_SIZE;
1303         entry = &bat_priv->bla.bcast_duplist[curr];
1304         entry->crc = crc;
1305         entry->entrytime = jiffies;
1306         memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
1307         bat_priv->bla.bcast_duplist_curr = curr;
1308
1309 out:
1310         spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1311
1312         return ret;
1313 }
1314
1315
1316
1317 /* @bat_priv: the bat priv with all the soft interface information
1318  * @orig: originator mac address
1319  *
1320  * check if the originator is a gateway for any VLAN ID.
1321  *
1322  * returns 1 if it is found, 0 otherwise
1323  */
1324 int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig)
1325 {
1326         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1327         struct hlist_head *head;
1328         struct hlist_node *node;
1329         struct batadv_backbone_gw *backbone_gw;
1330         int i;
1331
1332         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1333                 return 0;
1334
1335         if (!hash)
1336                 return 0;
1337
1338         for (i = 0; i < hash->size; i++) {
1339                 head = &hash->table[i];
1340
1341                 rcu_read_lock();
1342                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1343                         if (batadv_compare_eth(backbone_gw->orig, orig)) {
1344                                 rcu_read_unlock();
1345                                 return 1;
1346                         }
1347                 }
1348                 rcu_read_unlock();
1349         }
1350
1351         return 0;
1352 }
1353
1354
1355 /**
1356  * batadv_bla_is_backbone_gw
1357  * @skb: the frame to be checked
1358  * @orig_node: the orig_node of the frame
1359  * @hdr_size: maximum length of the frame
1360  *
1361  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1362  * if the orig_node is also a gateway on the soft interface, otherwise it
1363  * returns 0.
1364  */
1365 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1366                               struct batadv_orig_node *orig_node, int hdr_size)
1367 {
1368         struct ethhdr *ethhdr;
1369         struct vlan_ethhdr *vhdr;
1370         struct batadv_backbone_gw *backbone_gw;
1371         short vid = -1;
1372
1373         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1374                 return 0;
1375
1376         /* first, find out the vid. */
1377         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1378                 return 0;
1379
1380         ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);
1381
1382         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
1383                 if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
1384                         return 0;
1385
1386                 vhdr = (struct vlan_ethhdr *)(skb->data + hdr_size);
1387                 vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
1388         }
1389
1390         /* see if this originator is a backbone gw for this VLAN */
1391         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1392                                                 orig_node->orig, vid);
1393         if (!backbone_gw)
1394                 return 0;
1395
1396         batadv_backbone_gw_free_ref(backbone_gw);
1397         return 1;
1398 }
1399
1400 /* free all bla structures (for softinterface free or module unload) */
1401 void batadv_bla_free(struct batadv_priv *bat_priv)
1402 {
1403         struct batadv_hard_iface *primary_if;
1404
1405         cancel_delayed_work_sync(&bat_priv->bla.work);
1406         primary_if = batadv_primary_if_get_selected(bat_priv);
1407
1408         if (bat_priv->bla.claim_hash) {
1409                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1410                 batadv_hash_destroy(bat_priv->bla.claim_hash);
1411                 bat_priv->bla.claim_hash = NULL;
1412         }
1413         if (bat_priv->bla.backbone_hash) {
1414                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1415                 batadv_hash_destroy(bat_priv->bla.backbone_hash);
1416                 bat_priv->bla.backbone_hash = NULL;
1417         }
1418         if (primary_if)
1419                 batadv_hardif_free_ref(primary_if);
1420 }
1421
1422 /**
1423  * batadv_bla_rx
1424  * @bat_priv: the bat priv with all the soft interface information
1425  * @skb: the frame to be checked
1426  * @vid: the VLAN ID of the frame
1427  * @is_bcast: the packet came in a broadcast packet type.
1428  *
1429  * bla_rx avoidance checks if:
1430  *  * we have to race for a claim
1431  *  * if the frame is allowed on the LAN
1432  *
1433  * in these cases, the skb is further handled by this function and
1434  * returns 1, otherwise it returns 0 and the caller shall further
1435  * process the skb.
1436  */
1437 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid,
1438                   bool is_bcast)
1439 {
1440         struct ethhdr *ethhdr;
1441         struct batadv_claim search_claim, *claim = NULL;
1442         struct batadv_hard_iface *primary_if;
1443         int ret;
1444
1445         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1446
1447         primary_if = batadv_primary_if_get_selected(bat_priv);
1448         if (!primary_if)
1449                 goto handled;
1450
1451         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1452                 goto allow;
1453
1454
1455         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1456                 /* don't allow broadcasts while requests are in flight */
1457                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1458                         goto handled;
1459
1460         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1461         search_claim.vid = vid;
1462         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1463
1464         if (!claim) {
1465                 /* possible optimization: race for a claim */
1466                 /* No claim exists yet, claim it for us!
1467                  */
1468                 batadv_handle_claim(bat_priv, primary_if,
1469                                     primary_if->net_dev->dev_addr,
1470                                     ethhdr->h_source, vid);
1471                 goto allow;
1472         }
1473
1474         /* if it is our own claim ... */
1475         if (batadv_compare_eth(claim->backbone_gw->orig,
1476                                primary_if->net_dev->dev_addr)) {
1477                 /* ... allow it in any case */
1478                 claim->lasttime = jiffies;
1479                 goto allow;
1480         }
1481
1482         /* if it is a broadcast ... */
1483         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1484                 /* ... drop it. the responsible gateway is in charge.
1485                  *
1486                  * We need to check is_bcast because with the gateway
1487                  * feature, broadcasts (like DHCP requests) may be sent
1488                  * using a unicast packet type.
1489                  */
1490                 goto handled;
1491         } else {
1492                 /* seems the client considers us as its best gateway.
1493                  * send a claim and update the claim table
1494                  * immediately.
1495                  */
1496                 batadv_handle_claim(bat_priv, primary_if,
1497                                     primary_if->net_dev->dev_addr,
1498                                     ethhdr->h_source, vid);
1499                 goto allow;
1500         }
1501 allow:
1502         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1503         ret = 0;
1504         goto out;
1505
1506 handled:
1507         kfree_skb(skb);
1508         ret = 1;
1509
1510 out:
1511         if (primary_if)
1512                 batadv_hardif_free_ref(primary_if);
1513         if (claim)
1514                 batadv_claim_free_ref(claim);
1515         return ret;
1516 }
1517
1518 /**
1519  * batadv_bla_tx
1520  * @bat_priv: the bat priv with all the soft interface information
1521  * @skb: the frame to be checked
1522  * @vid: the VLAN ID of the frame
1523  *
1524  * bla_tx checks if:
1525  *  * a claim was received which has to be processed
1526  *  * the frame is allowed on the mesh
1527  *
1528  * in these cases, the skb is further handled by this function and
1529  * returns 1, otherwise it returns 0 and the caller shall further
1530  * process the skb.
1531  */
1532 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid)
1533 {
1534         struct ethhdr *ethhdr;
1535         struct batadv_claim search_claim, *claim = NULL;
1536         struct batadv_hard_iface *primary_if;
1537         int ret = 0;
1538
1539         primary_if = batadv_primary_if_get_selected(bat_priv);
1540         if (!primary_if)
1541                 goto out;
1542
1543         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1544                 goto allow;
1545
1546         /* in VLAN case, the mac header might not be set. */
1547         skb_reset_mac_header(skb);
1548
1549         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1550                 goto handled;
1551
1552         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1553
1554         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1555                 /* don't allow broadcasts while requests are in flight */
1556                 if (is_multicast_ether_addr(ethhdr->h_dest))
1557                         goto handled;
1558
1559         memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
1560         search_claim.vid = vid;
1561
1562         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1563
1564         /* if no claim exists, allow it. */
1565         if (!claim)
1566                 goto allow;
1567
1568         /* check if we are responsible. */
1569         if (batadv_compare_eth(claim->backbone_gw->orig,
1570                                primary_if->net_dev->dev_addr)) {
1571                 /* if yes, the client has roamed and we have
1572                  * to unclaim it.
1573                  */
1574                 batadv_handle_unclaim(bat_priv, primary_if,
1575                                       primary_if->net_dev->dev_addr,
1576                                       ethhdr->h_source, vid);
1577                 goto allow;
1578         }
1579
1580         /* check if it is a multicast/broadcast frame */
1581         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1582                 /* drop it. the responsible gateway has forwarded it into
1583                  * the backbone network.
1584                  */
1585                 goto handled;
1586         } else {
1587                 /* we must allow it. at least if we are
1588                  * responsible for the DESTINATION.
1589                  */
1590                 goto allow;
1591         }
1592 allow:
1593         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1594         ret = 0;
1595         goto out;
1596 handled:
1597         ret = 1;
1598 out:
1599         if (primary_if)
1600                 batadv_hardif_free_ref(primary_if);
1601         if (claim)
1602                 batadv_claim_free_ref(claim);
1603         return ret;
1604 }
1605
1606 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1607 {
1608         struct net_device *net_dev = (struct net_device *)seq->private;
1609         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1610         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
1611         struct batadv_claim *claim;
1612         struct batadv_hard_iface *primary_if;
1613         struct hlist_node *node;
1614         struct hlist_head *head;
1615         uint32_t i;
1616         bool is_own;
1617         uint8_t *primary_addr;
1618
1619         primary_if = batadv_seq_print_text_primary_if_get(seq);
1620         if (!primary_if)
1621                 goto out;
1622
1623         primary_addr = primary_if->net_dev->dev_addr;
1624         seq_printf(seq,
1625                    "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
1626                    net_dev->name, primary_addr,
1627                    ntohs(bat_priv->bla.claim_dest.group));
1628         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-6s)\n",
1629                    "Client", "VID", "Originator", "CRC");
1630         for (i = 0; i < hash->size; i++) {
1631                 head = &hash->table[i];
1632
1633                 rcu_read_lock();
1634                 hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
1635                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1636                                                     primary_addr);
1637                         seq_printf(seq, " * %pM on % 5d by %pM [%c] (%#.4x)\n",
1638                                    claim->addr, claim->vid,
1639                                    claim->backbone_gw->orig,
1640                                    (is_own ? 'x' : ' '),
1641                                    claim->backbone_gw->crc);
1642                 }
1643                 rcu_read_unlock();
1644         }
1645 out:
1646         if (primary_if)
1647                 batadv_hardif_free_ref(primary_if);
1648         return 0;
1649 }
1650
1651 int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
1652 {
1653         struct net_device *net_dev = (struct net_device *)seq->private;
1654         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1655         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1656         struct batadv_backbone_gw *backbone_gw;
1657         struct batadv_hard_iface *primary_if;
1658         struct hlist_node *node;
1659         struct hlist_head *head;
1660         int secs, msecs;
1661         uint32_t i;
1662         bool is_own;
1663         uint8_t *primary_addr;
1664
1665         primary_if = batadv_seq_print_text_primary_if_get(seq);
1666         if (!primary_if)
1667                 goto out;
1668
1669         primary_addr = primary_if->net_dev->dev_addr;
1670         seq_printf(seq,
1671                    "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
1672                    net_dev->name, primary_addr,
1673                    ntohs(bat_priv->bla.claim_dest.group));
1674         seq_printf(seq, "   %-17s    %-5s %-9s (%-6s)\n",
1675                    "Originator", "VID", "last seen", "CRC");
1676         for (i = 0; i < hash->size; i++) {
1677                 head = &hash->table[i];
1678
1679                 rcu_read_lock();
1680                 hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
1681                         msecs = jiffies_to_msecs(jiffies -
1682                                                  backbone_gw->lasttime);
1683                         secs = msecs / 1000;
1684                         msecs = msecs % 1000;
1685
1686                         is_own = batadv_compare_eth(backbone_gw->orig,
1687                                                     primary_addr);
1688                         if (is_own)
1689                                 continue;
1690
1691                         seq_printf(seq,
1692                                    " * %pM on % 5d % 4i.%03is (%#.4x)\n",
1693                                    backbone_gw->orig, backbone_gw->vid,
1694                                    secs, msecs, backbone_gw->crc);
1695                 }
1696                 rcu_read_unlock();
1697         }
1698 out:
1699         if (primary_if)
1700                 batadv_hardif_free_ref(primary_if);
1701         return 0;
1702 }