net/batman-adv/bridge_loop_avoidance.c

   1 /* Copyright (C) 2011-2015 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 "bridge_loop_avoidance.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/crc16.h>
  25 #include <linux/errno.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/fs.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/if_vlan.h>
  31 #include <linux/jhash.h>
  32 #include <linux/jiffies.h>
  33 #include <linux/kernel.h>
  34 #include <linux/list.h>
  35 #include <linux/lockdep.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/rculist.h>
  38 #include <linux/rcupdate.h>
  39 #include <linux/seq_file.h>
  40 #include <linux/skbuff.h>
  41 #include <linux/slab.h>
  42 #include <linux/spinlock.h>
  43 #include <linux/stddef.h>
  44 #include <linux/string.h>
  45 #include <linux/workqueue.h>
  46 #include <net/arp.h>
  47
  48 #include "hard-interface.h"
  49 #include "hash.h"
  50 #include "originator.h"
  51 #include "packet.h"
  52 #include "translation-table.h"
  53
  54 static const u8 batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
  55
  56 static void batadv_bla_periodic_work(struct work_struct *work);
  57 static void
  58 batadv_bla_send_announce(struct batadv_priv *bat_priv,
  59                          struct batadv_bla_backbone_gw *backbone_gw);
  60
  61 /* return the index of the claim */
  62 static inline u32 batadv_choose_claim(const void *data, u32 size)
  63 {
  64         struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  65         u32 hash = 0;
  66
  67         hash = jhash(&claim->addr, sizeof(claim->addr), hash);
  68         hash = jhash(&claim->vid, sizeof(claim->vid), hash);
  69
  70         return hash % size;
  71 }
  72
  73 /* return the index of the backbone gateway */
  74 static inline u32 batadv_choose_backbone_gw(const void *data, u32 size)
  75 {
  76         const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  77         u32 hash = 0;
  78
  79         hash = jhash(&claim->addr, sizeof(claim->addr), hash);
  80         hash = jhash(&claim->vid, sizeof(claim->vid), hash);
  81
  82         return hash % size;
  83 }
  84
  85 /* compares address and vid of two backbone gws */
  86 static int batadv_compare_backbone_gw(const struct hlist_node *node,
  87                                       const void *data2)
  88 {
  89         const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
  90                                          hash_entry);
  91         const struct batadv_bla_backbone_gw *gw1 = data1;
  92         const struct batadv_bla_backbone_gw *gw2 = data2;
  93
  94         if (!batadv_compare_eth(gw1->orig, gw2->orig))
  95                 return 0;
  96
  97         if (gw1->vid != gw2->vid)
  98                 return 0;
  99
 100         return 1;
 101 }
 102
 103 /* compares address and vid of two claims */
 104 static int batadv_compare_claim(const struct hlist_node *node,
 105                                 const void *data2)
 106 {
 107         const void *data1 = container_of(node, struct batadv_bla_claim,
 108                                          hash_entry);
 109         const struct batadv_bla_claim *cl1 = data1;
 110         const struct batadv_bla_claim *cl2 = data2;
 111
 112         if (!batadv_compare_eth(cl1->addr, cl2->addr))
 113                 return 0;
 114
 115         if (cl1->vid != cl2->vid)
 116                 return 0;
 117
 118         return 1;
 119 }
 120
 121 /* free a backbone gw */
 122 static void
 123 batadv_backbone_gw_free_ref(struct batadv_bla_backbone_gw *backbone_gw)
 124 {
 125         if (atomic_dec_and_test(&backbone_gw->refcount))
 126                 kfree_rcu(backbone_gw, rcu);
 127 }
 128
 129 /* finally deinitialize the claim */
 130 static void batadv_claim_free_rcu(struct rcu_head *rcu)
 131 {
 132         struct batadv_bla_claim *claim;
 133
 134         claim = container_of(rcu, struct batadv_bla_claim, rcu);
 135
 136         batadv_backbone_gw_free_ref(claim->backbone_gw);
 137         kfree(claim);
 138 }
 139
 140 /* free a claim, call claim_free_rcu if its the last reference */
 141 static void batadv_claim_free_ref(struct batadv_bla_claim *claim)
 142 {
 143         if (atomic_dec_and_test(&claim->refcount))
 144                 call_rcu(&claim->rcu, batadv_claim_free_rcu);
 145 }
 146
 147 /**
 148  * batadv_claim_hash_find
 149  * @bat_priv: the bat priv with all the soft interface information
 150  * @data: search data (may be local/static data)
 151  *
 152  * looks for a claim in the hash, and returns it if found
 153  * or NULL otherwise.
 154  */
 155 static struct batadv_bla_claim
 156 *batadv_claim_hash_find(struct batadv_priv *bat_priv,
 157                         struct batadv_bla_claim *data)
 158 {
 159         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
 160         struct hlist_head *head;
 161         struct batadv_bla_claim *claim;
 162         struct batadv_bla_claim *claim_tmp = NULL;
 163         int index;
 164
 165         if (!hash)
 166                 return NULL;
 167
 168         index = batadv_choose_claim(data, hash->size);
 169         head = &hash->table[index];
 170
 171         rcu_read_lock();
 172         hlist_for_each_entry_rcu(claim, head, hash_entry) {
 173                 if (!batadv_compare_claim(&claim->hash_entry, data))
 174                         continue;
 175
 176                 if (!atomic_inc_not_zero(&claim->refcount))
 177                         continue;
 178
 179                 claim_tmp = claim;
 180                 break;
 181         }
 182         rcu_read_unlock();
 183
 184         return claim_tmp;
 185 }
 186
 187 /**
 188  * batadv_backbone_hash_find - looks for a claim in the hash
 189  * @bat_priv: the bat priv with all the soft interface information
 190  * @addr: the address of the originator
 191  * @vid: the VLAN ID
 192  *
 193  * Returns claim if found or NULL otherwise.
 194  */
 195 static struct batadv_bla_backbone_gw *
 196 batadv_backbone_hash_find(struct batadv_priv *bat_priv, u8 *addr,
 197                           unsigned short vid)
 198 {
 199         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
 200         struct hlist_head *head;
 201         struct batadv_bla_backbone_gw search_entry, *backbone_gw;
 202         struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
 203         int index;
 204
 205         if (!hash)
 206                 return NULL;
 207
 208         ether_addr_copy(search_entry.orig, addr);
 209         search_entry.vid = vid;
 210
 211         index = batadv_choose_backbone_gw(&search_entry, hash->size);
 212         head = &hash->table[index];
 213
 214         rcu_read_lock();
 215         hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
 216                 if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
 217                                                 &search_entry))
 218                         continue;
 219
 220                 if (!atomic_inc_not_zero(&backbone_gw->refcount))
 221                         continue;
 222
 223                 backbone_gw_tmp = backbone_gw;
 224                 break;
 225         }
 226         rcu_read_unlock();
 227
 228         return backbone_gw_tmp;
 229 }
 230
 231 /* delete all claims for a backbone */
 232 static void
 233 batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
 234 {
 235         struct batadv_hashtable *hash;
 236         struct hlist_node *node_tmp;
 237         struct hlist_head *head;
 238         struct batadv_bla_claim *claim;
 239         int i;
 240         spinlock_t *list_lock;  /* protects write access to the hash lists */
 241
 242         hash = backbone_gw->bat_priv->bla.claim_hash;
 243         if (!hash)
 244                 return;
 245
 246         for (i = 0; i < hash->size; i++) {
 247                 head = &hash->table[i];
 248                 list_lock = &hash->list_locks[i];
 249
 250                 spin_lock_bh(list_lock);
 251                 hlist_for_each_entry_safe(claim, node_tmp,
 252                                           head, hash_entry) {
 253                         if (claim->backbone_gw != backbone_gw)
 254                                 continue;
 255
 256                         batadv_claim_free_ref(claim);
 257                         hlist_del_rcu(&claim->hash_entry);
 258                 }
 259                 spin_unlock_bh(list_lock);
 260         }
 261
 262         /* all claims gone, initialize CRC */
 263         spin_lock_bh(&backbone_gw->crc_lock);
 264         backbone_gw->crc = BATADV_BLA_CRC_INIT;
 265         spin_unlock_bh(&backbone_gw->crc_lock);
 266 }
 267
 268 /**
 269  * batadv_bla_send_claim - sends a claim frame according to the provided info
 270  * @bat_priv: the bat priv with all the soft interface information
 271  * @mac: the mac address to be announced within the claim
 272  * @vid: the VLAN ID
 273  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 274  */
 275 static void batadv_bla_send_claim(struct batadv_priv *bat_priv, u8 *mac,
 276                                   unsigned short vid, int claimtype)
 277 {
 278         struct sk_buff *skb;
 279         struct ethhdr *ethhdr;
 280         struct batadv_hard_iface *primary_if;
 281         struct net_device *soft_iface;
 282         u8 *hw_src;
 283         struct batadv_bla_claim_dst local_claim_dest;
 284         __be32 zeroip = 0;
 285
 286         primary_if = batadv_primary_if_get_selected(bat_priv);
 287         if (!primary_if)
 288                 return;
 289
 290         memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
 291                sizeof(local_claim_dest));
 292         local_claim_dest.type = claimtype;
 293
 294         soft_iface = primary_if->soft_iface;
 295
 296         skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
 297                          /* IP DST: 0.0.0.0 */
 298                          zeroip,
 299                          primary_if->soft_iface,
 300                          /* IP SRC: 0.0.0.0 */
 301                          zeroip,
 302                          /* Ethernet DST: Broadcast */
 303                          NULL,
 304                          /* Ethernet SRC/HW SRC:  originator mac */
 305                          primary_if->net_dev->dev_addr,
 306                          /* HW DST: FF:43:05:XX:YY:YY
 307                           * with XX   = claim type
 308                           * and YY:YY = group id
 309                           */
 310                          (u8 *)&local_claim_dest);
 311
 312         if (!skb)
 313                 goto out;
 314
 315         ethhdr = (struct ethhdr *)skb->data;
 316         hw_src = (u8 *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
 317
 318         /* now we pretend that the client would have sent this ... */
 319         switch (claimtype) {
 320         case BATADV_CLAIM_TYPE_CLAIM:
 321                 /* normal claim frame
 322                  * set Ethernet SRC to the clients mac
 323                  */
 324                 ether_addr_copy(ethhdr->h_source, mac);
 325                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 326                            "bla_send_claim(): CLAIM %pM on vid %d\n", mac,
 327                            BATADV_PRINT_VID(vid));
 328                 break;
 329         case BATADV_CLAIM_TYPE_UNCLAIM:
 330                 /* unclaim frame
 331                  * set HW SRC to the clients mac
 332                  */
 333                 ether_addr_copy(hw_src, mac);
 334                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 335                            "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
 336                            BATADV_PRINT_VID(vid));
 337                 break;
 338         case BATADV_CLAIM_TYPE_ANNOUNCE:
 339                 /* announcement frame
 340                  * set HW SRC to the special mac containg the crc
 341                  */
 342                 ether_addr_copy(hw_src, mac);
 343                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 344                            "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
 345                            ethhdr->h_source, BATADV_PRINT_VID(vid));
 346                 break;
 347         case BATADV_CLAIM_TYPE_REQUEST:
 348                 /* request frame
 349                  * set HW SRC and header destination to the receiving backbone
 350                  * gws mac
 351                  */
 352                 ether_addr_copy(hw_src, mac);
 353                 ether_addr_copy(ethhdr->h_dest, mac);
 354                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 355                            "bla_send_claim(): REQUEST of %pM to %pM on vid %d\n",
 356                            ethhdr->h_source, ethhdr->h_dest,
 357                            BATADV_PRINT_VID(vid));
 358                 break;
 359         }
 360
 361         if (vid & BATADV_VLAN_HAS_TAG)
 362                 skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
 363                                       vid & VLAN_VID_MASK);
 364
 365         skb_reset_mac_header(skb);
 366         skb->protocol = eth_type_trans(skb, soft_iface);
 367         batadv_inc_counter(bat_priv, BATADV_CNT_RX);
 368         batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
 369                            skb->len + ETH_HLEN);
 370         soft_iface->last_rx = jiffies;
 371
 372         netif_rx(skb);
 373 out:
 374         if (primary_if)
 375                 batadv_hardif_free_ref(primary_if);
 376 }
 377
 378 /**
 379  * batadv_bla_get_backbone_gw
 380  * @bat_priv: the bat priv with all the soft interface information
 381  * @orig: the mac address of the originator
 382  * @vid: the VLAN ID
 383  * @own_backbone: set if the requested backbone is local
 384  *
 385  * searches for the backbone gw or creates a new one if it could not
 386  * be found.
 387  */
 388 static struct batadv_bla_backbone_gw *
 389 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig,
 390                            unsigned short vid, bool own_backbone)
 391 {
 392         struct batadv_bla_backbone_gw *entry;
 393         struct batadv_orig_node *orig_node;
 394         int hash_added;
 395
 396         entry = batadv_backbone_hash_find(bat_priv, orig, vid);
 397
 398         if (entry)
 399                 return entry;
 400
 401         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 402                    "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
 403                    orig, BATADV_PRINT_VID(vid));
 404
 405         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 406         if (!entry)
 407                 return NULL;
 408
 409         entry->vid = vid;
 410         entry->lasttime = jiffies;
 411         entry->crc = BATADV_BLA_CRC_INIT;
 412         entry->bat_priv = bat_priv;
 413         spin_lock_init(&entry->crc_lock);
 414         atomic_set(&entry->request_sent, 0);
 415         atomic_set(&entry->wait_periods, 0);
 416         ether_addr_copy(entry->orig, orig);
 417
 418         /* one for the hash, one for returning */
 419         atomic_set(&entry->refcount, 2);
 420
 421         hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
 422                                      batadv_compare_backbone_gw,
 423                                      batadv_choose_backbone_gw, entry,
 424                                      &entry->hash_entry);
 425
 426         if (unlikely(hash_added != 0)) {
 427                 /* hash failed, free the structure */
 428                 kfree(entry);
 429                 return NULL;
 430         }
 431
 432         /* this is a gateway now, remove any TT entry on this VLAN */
 433         orig_node = batadv_orig_hash_find(bat_priv, orig);
 434         if (orig_node) {
 435                 batadv_tt_global_del_orig(bat_priv, orig_node, vid,
 436                                           "became a backbone gateway");
 437                 batadv_orig_node_free_ref(orig_node);
 438         }
 439
 440         if (own_backbone) {
 441                 batadv_bla_send_announce(bat_priv, entry);
 442
 443                 /* this will be decreased in the worker thread */
 444                 atomic_inc(&entry->request_sent);
 445                 atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
 446                 atomic_inc(&bat_priv->bla.num_requests);
 447         }
 448
 449         return entry;
 450 }
 451
 452 /* update or add the own backbone gw to make sure we announce
 453  * where we receive other backbone gws
 454  */
 455 static void
 456 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 457                                   struct batadv_hard_iface *primary_if,
 458                                   unsigned short vid)
 459 {
 460         struct batadv_bla_backbone_gw *backbone_gw;
 461
 462         backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 463                                                  primary_if->net_dev->dev_addr,
 464                                                  vid, true);
 465         if (unlikely(!backbone_gw))
 466                 return;
 467
 468         backbone_gw->lasttime = jiffies;
 469         batadv_backbone_gw_free_ref(backbone_gw);
 470 }
 471
 472 /**
 473  * batadv_bla_answer_request - answer a bla request by sending own claims
 474  * @bat_priv: the bat priv with all the soft interface information
 475  * @primary_if: interface where the request came on
 476  * @vid: the vid where the request came on
 477  *
 478  * Repeat all of our own claims, and finally send an ANNOUNCE frame
 479  * to allow the requester another check if the CRC is correct now.
 480  */
 481 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
 482                                       struct batadv_hard_iface *primary_if,
 483                                       unsigned short vid)
 484 {
 485         struct hlist_head *head;
 486         struct batadv_hashtable *hash;
 487         struct batadv_bla_claim *claim;
 488         struct batadv_bla_backbone_gw *backbone_gw;
 489         int i;
 490
 491         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 492                    "bla_answer_request(): received a claim request, send all of our own claims again\n");
 493
 494         backbone_gw = batadv_backbone_hash_find(bat_priv,
 495                                                 primary_if->net_dev->dev_addr,
 496                                                 vid);
 497         if (!backbone_gw)
 498                 return;
 499
 500         hash = bat_priv->bla.claim_hash;
 501         for (i = 0; i < hash->size; i++) {
 502                 head = &hash->table[i];
 503
 504                 rcu_read_lock();
 505                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
 506                         /* only own claims are interesting */
 507                         if (claim->backbone_gw != backbone_gw)
 508                                 continue;
 509
 510                         batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
 511                                               BATADV_CLAIM_TYPE_CLAIM);
 512                 }
 513                 rcu_read_unlock();
 514         }
 515
 516         /* finally, send an announcement frame */
 517         batadv_bla_send_announce(bat_priv, backbone_gw);
 518         batadv_backbone_gw_free_ref(backbone_gw);
 519 }
 520
 521 /**
 522  * batadv_bla_send_request - send a request to repeat claims
 523  * @backbone_gw: the backbone gateway from whom we are out of sync
 524  *
 525  * When the crc is wrong, ask the backbone gateway for a full table update.
 526  * After the request, it will repeat all of his own claims and finally
 527  * send an announcement claim with which we can check again.
 528  */
 529 static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw)
 530 {
 531         /* first, remove all old entries */
 532         batadv_bla_del_backbone_claims(backbone_gw);
 533
 534         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 535                    "Sending REQUEST to %pM\n", backbone_gw->orig);
 536
 537         /* send request */
 538         batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
 539                               backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
 540
 541         /* no local broadcasts should be sent or received, for now. */
 542         if (!atomic_read(&backbone_gw->request_sent)) {
 543                 atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
 544                 atomic_set(&backbone_gw->request_sent, 1);
 545         }
 546 }
 547
 548 /**
 549  * batadv_bla_send_announce
 550  * @bat_priv: the bat priv with all the soft interface information
 551  * @backbone_gw: our backbone gateway which should be announced
 552  *
 553  * This function sends an announcement. It is called from multiple
 554  * places.
 555  */
 556 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 557                                      struct batadv_bla_backbone_gw *backbone_gw)
 558 {
 559         u8 mac[ETH_ALEN];
 560         __be16 crc;
 561
 562         memcpy(mac, batadv_announce_mac, 4);
 563         spin_lock_bh(&backbone_gw->crc_lock);
 564         crc = htons(backbone_gw->crc);
 565         spin_unlock_bh(&backbone_gw->crc_lock);
 566         memcpy(&mac[4], &crc, 2);
 567
 568         batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
 569                               BATADV_CLAIM_TYPE_ANNOUNCE);
 570 }
 571
 572 /**
 573  * batadv_bla_add_claim - Adds a claim in the claim hash
 574  * @bat_priv: the bat priv with all the soft interface information
 575  * @mac: the mac address of the claim
 576  * @vid: the VLAN ID of the frame
 577  * @backbone_gw: the backbone gateway which claims it
 578  */
 579 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
 580                                  const u8 *mac, const unsigned short vid,
 581                                  struct batadv_bla_backbone_gw *backbone_gw)
 582 {
 583         struct batadv_bla_claim *claim;
 584         struct batadv_bla_claim search_claim;
 585         int hash_added;
 586
 587         ether_addr_copy(search_claim.addr, mac);
 588         search_claim.vid = vid;
 589         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 590
 591         /* create a new claim entry if it does not exist yet. */
 592         if (!claim) {
 593                 claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
 594                 if (!claim)
 595                         return;
 596
 597                 ether_addr_copy(claim->addr, mac);
 598                 claim->vid = vid;
 599                 claim->lasttime = jiffies;
 600                 claim->backbone_gw = backbone_gw;
 601
 602                 atomic_set(&claim->refcount, 2);
 603                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 604                            "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
 605                            mac, BATADV_PRINT_VID(vid));
 606                 hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
 607                                              batadv_compare_claim,
 608                                              batadv_choose_claim, claim,
 609                                              &claim->hash_entry);
 610
 611                 if (unlikely(hash_added != 0)) {
 612                         /* only local changes happened. */
 613                         kfree(claim);
 614                         return;
 615                 }
 616         } else {
 617                 claim->lasttime = jiffies;
 618                 if (claim->backbone_gw == backbone_gw)
 619                         /* no need to register a new backbone */
 620                         goto claim_free_ref;
 621
 622                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 623                            "bla_add_claim(): changing ownership for %pM, vid %d\n",
 624                            mac, BATADV_PRINT_VID(vid));
 625
 626                 spin_lock_bh(&claim->backbone_gw->crc_lock);
 627                 claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 628                 spin_unlock_bh(&claim->backbone_gw->crc_lock);
 629                 batadv_backbone_gw_free_ref(claim->backbone_gw);
 630         }
 631         /* set (new) backbone gw */
 632         atomic_inc(&backbone_gw->refcount);
 633         claim->backbone_gw = backbone_gw;
 634
 635         spin_lock_bh(&backbone_gw->crc_lock);
 636         backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 637         spin_unlock_bh(&backbone_gw->crc_lock);
 638         backbone_gw->lasttime = jiffies;
 639
 640 claim_free_ref:
 641         batadv_claim_free_ref(claim);
 642 }
 643
 644 /* Delete a claim from the claim hash which has the
 645  * given mac address and vid.
 646  */
 647 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
 648                                  const u8 *mac, const unsigned short vid)
 649 {
 650         struct batadv_bla_claim search_claim, *claim;
 651
 652         ether_addr_copy(search_claim.addr, mac);
 653         search_claim.vid = vid;
 654         claim = batadv_claim_hash_find(bat_priv, &search_claim);
 655         if (!claim)
 656                 return;
 657
 658         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
 659                    mac, BATADV_PRINT_VID(vid));
 660
 661         batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
 662                            batadv_choose_claim, claim);
 663         batadv_claim_free_ref(claim); /* reference from the hash is gone */
 664
 665         spin_lock_bh(&claim->backbone_gw->crc_lock);
 666         claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
 667         spin_unlock_bh(&claim->backbone_gw->crc_lock);
 668
 669         /* don't need the reference from hash_find() anymore */
 670         batadv_claim_free_ref(claim);
 671 }
 672
 673 /* check for ANNOUNCE frame, return 1 if handled */
 674 static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
 675                                   u8 *backbone_addr, unsigned short vid)
 676 {
 677         struct batadv_bla_backbone_gw *backbone_gw;
 678         u16 backbone_crc, crc;
 679
 680         if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 681                 return 0;
 682
 683         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 684                                                  false);
 685
 686         if (unlikely(!backbone_gw))
 687                 return 1;
 688
 689         /* handle as ANNOUNCE frame */
 690         backbone_gw->lasttime = jiffies;
 691         crc = ntohs(*((__be16 *)(&an_addr[4])));
 692
 693         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 694                    "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
 695                    BATADV_PRINT_VID(vid), backbone_gw->orig, crc);
 696
 697         spin_lock_bh(&backbone_gw->crc_lock);
 698         backbone_crc = backbone_gw->crc;
 699         spin_unlock_bh(&backbone_gw->crc_lock);
 700
 701         if (backbone_crc != crc) {
 702                 batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
 703                            "handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
 704                            backbone_gw->orig,
 705                            BATADV_PRINT_VID(backbone_gw->vid),
 706                            backbone_crc, crc);
 707
 708                 batadv_bla_send_request(backbone_gw);
 709         } else {
 710                 /* if we have sent a request and the crc was OK,
 711                  * we can allow traffic again.
 712                  */
 713                 if (atomic_read(&backbone_gw->request_sent)) {
 714                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
 715                         atomic_set(&backbone_gw->request_sent, 0);
 716                 }
 717         }
 718
 719         batadv_backbone_gw_free_ref(backbone_gw);
 720         return 1;
 721 }
 722
 723 /* check for REQUEST frame, return 1 if handled */
 724 static int batadv_handle_request(struct batadv_priv *bat_priv,
 725                                  struct batadv_hard_iface *primary_if,
 726                                  u8 *backbone_addr, struct ethhdr *ethhdr,
 727                                  unsigned short vid)
 728 {
 729         /* check for REQUEST frame */
 730         if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
 731                 return 0;
 732
 733         /* sanity check, this should not happen on a normal switch,
 734          * we ignore it in this case.
 735          */
 736         if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
 737                 return 1;
 738
 739         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 740                    "handle_request(): REQUEST vid %d (sent by %pM)...\n",
 741                    BATADV_PRINT_VID(vid), ethhdr->h_source);
 742
 743         batadv_bla_answer_request(bat_priv, primary_if, vid);
 744         return 1;
 745 }
 746
 747 /* check for UNCLAIM frame, return 1 if handled */
 748 static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
 749                                  struct batadv_hard_iface *primary_if,
 750                                  u8 *backbone_addr, u8 *claim_addr,
 751                                  unsigned short vid)
 752 {
 753         struct batadv_bla_backbone_gw *backbone_gw;
 754
 755         /* unclaim in any case if it is our own */
 756         if (primary_if && batadv_compare_eth(backbone_addr,
 757                                              primary_if->net_dev->dev_addr))
 758                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 759                                       BATADV_CLAIM_TYPE_UNCLAIM);
 760
 761         backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
 762
 763         if (!backbone_gw)
 764                 return 1;
 765
 766         /* this must be an UNCLAIM frame */
 767         batadv_dbg(BATADV_DBG_BLA, bat_priv,
 768                    "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
 769                    claim_addr, BATADV_PRINT_VID(vid), backbone_gw->orig);
 770
 771         batadv_bla_del_claim(bat_priv, claim_addr, vid);
 772         batadv_backbone_gw_free_ref(backbone_gw);
 773         return 1;
 774 }
 775
 776 /* check for CLAIM frame, return 1 if handled */
 777 static int batadv_handle_claim(struct batadv_priv *bat_priv,
 778                                struct batadv_hard_iface *primary_if,
 779                                u8 *backbone_addr, u8 *claim_addr,
 780                                unsigned short vid)
 781 {
 782         struct batadv_bla_backbone_gw *backbone_gw;
 783
 784         /* register the gateway if not yet available, and add the claim. */
 785
 786         backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
 787                                                  false);
 788
 789         if (unlikely(!backbone_gw))
 790                 return 1;
 791
 792         /* this must be a CLAIM frame */
 793         batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
 794         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 795                 batadv_bla_send_claim(bat_priv, claim_addr, vid,
 796                                       BATADV_CLAIM_TYPE_CLAIM);
 797
 798         /* TODO: we could call something like tt_local_del() here. */
 799
 800         batadv_backbone_gw_free_ref(backbone_gw);
 801         return 1;
 802 }
 803
 804 /**
 805  * batadv_check_claim_group
 806  * @bat_priv: the bat priv with all the soft interface information
 807  * @primary_if: the primary interface of this batman interface
 808  * @hw_src: the Hardware source in the ARP Header
 809  * @hw_dst: the Hardware destination in the ARP Header
 810  * @ethhdr: pointer to the Ethernet header of the claim frame
 811  *
 812  * checks if it is a claim packet and if its on the same group.
 813  * This function also applies the group ID of the sender
 814  * if it is in the same mesh.
 815  *
 816  * returns:
 817  *      2  - if it is a claim packet and on the same group
 818  *      1  - if is a claim packet from another group
 819  *      0  - if it is not a claim packet
 820  */
 821 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 822                                     struct batadv_hard_iface *primary_if,
 823                                     u8 *hw_src, u8 *hw_dst,
 824                                     struct ethhdr *ethhdr)
 825 {
 826         u8 *backbone_addr;
 827         struct batadv_orig_node *orig_node;
 828         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 829
 830         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 831         bla_dst_own = &bat_priv->bla.claim_dest;
 832
 833         /* if announcement packet, use the source,
 834          * otherwise assume it is in the hw_src
 835          */
 836         switch (bla_dst->type) {
 837         case BATADV_CLAIM_TYPE_CLAIM:
 838                 backbone_addr = hw_src;
 839                 break;
 840         case BATADV_CLAIM_TYPE_REQUEST:
 841         case BATADV_CLAIM_TYPE_ANNOUNCE:
 842         case BATADV_CLAIM_TYPE_UNCLAIM:
 843                 backbone_addr = ethhdr->h_source;
 844                 break;
 845         default:
 846                 return 0;
 847         }
 848
 849         /* don't accept claim frames from ourselves */
 850         if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
 851                 return 0;
 852
 853         /* if its already the same group, it is fine. */
 854         if (bla_dst->group == bla_dst_own->group)
 855                 return 2;
 856
 857         /* lets see if this originator is in our mesh */
 858         orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
 859
 860         /* dont accept claims from gateways which are not in
 861          * the same mesh or group.
 862          */
 863         if (!orig_node)
 864                 return 1;
 865
 866         /* if our mesh friends mac is bigger, use it for ourselves. */
 867         if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
 868                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 869                            "taking other backbones claim group: %#.4x\n",
 870                            ntohs(bla_dst->group));
 871                 bla_dst_own->group = bla_dst->group;
 872         }
 873
 874         batadv_orig_node_free_ref(orig_node);
 875
 876         return 2;
 877 }
 878
 879 /**
 880  * batadv_bla_process_claim
 881  * @bat_priv: the bat priv with all the soft interface information
 882  * @primary_if: the primary hard interface of this batman soft interface
 883  * @skb: the frame to be checked
 884  *
 885  * Check if this is a claim frame, and process it accordingly.
 886  *
 887  * returns 1 if it was a claim frame, otherwise return 0 to
 888  * tell the callee that it can use the frame on its own.
 889  */
 890 static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 891                                     struct batadv_hard_iface *primary_if,
 892                                     struct sk_buff *skb)
 893 {
 894         struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 895         u8 *hw_src, *hw_dst;
 896         struct vlan_hdr *vhdr, vhdr_buf;
 897         struct ethhdr *ethhdr;
 898         struct arphdr *arphdr;
 899         unsigned short vid;
 900         int vlan_depth = 0;
 901         __be16 proto;
 902         int headlen;
 903         int ret;
 904
 905         vid = batadv_get_vid(skb, 0);
 906         ethhdr = eth_hdr(skb);
 907
 908         proto = ethhdr->h_proto;
 909         headlen = ETH_HLEN;
 910         if (vid & BATADV_VLAN_HAS_TAG) {
 911                 /* Traverse the VLAN/Ethertypes.
 912                  *
 913                  * At this point it is known that the first protocol is a VLAN
 914                  * header, so start checking at the encapsulated protocol.
 915                  *
 916                  * The depth of the VLAN headers is recorded to drop BLA claim
 917                  * frames encapsulated into multiple VLAN headers (QinQ).
 918                  */
 919                 do {
 920                         vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
 921                                                   &vhdr_buf);
 922                         if (!vhdr)
 923                                 return 0;
 924
 925                         proto = vhdr->h_vlan_encapsulated_proto;
 926                         headlen += VLAN_HLEN;
 927                         vlan_depth++;
 928                 } while (proto == htons(ETH_P_8021Q));
 929         }
 930
 931         if (proto != htons(ETH_P_ARP))
 932                 return 0; /* not a claim frame */
 933
 934         /* this must be a ARP frame. check if it is a claim. */
 935
 936         if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
 937                 return 0;
 938
 939         /* pskb_may_pull() may have modified the pointers, get ethhdr again */
 940         ethhdr = eth_hdr(skb);
 941         arphdr = (struct arphdr *)((u8 *)ethhdr + headlen);
 942
 943         /* Check whether the ARP frame carries a valid
 944          * IP information
 945          */
 946         if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
 947                 return 0;
 948         if (arphdr->ar_pro != htons(ETH_P_IP))
 949                 return 0;
 950         if (arphdr->ar_hln != ETH_ALEN)
 951                 return 0;
 952         if (arphdr->ar_pln != 4)
 953                 return 0;
 954
 955         hw_src = (u8 *)arphdr + sizeof(struct arphdr);
 956         hw_dst = hw_src + ETH_ALEN + 4;
 957         bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 958         bla_dst_own = &bat_priv->bla.claim_dest;
 959
 960         /* check if it is a claim frame in general */
 961         if (memcmp(bla_dst->magic, bla_dst_own->magic,
 962                    sizeof(bla_dst->magic)) != 0)
 963                 return 0;
 964
 965         /* check if there is a claim frame encapsulated deeper in (QinQ) and
 966          * drop that, as this is not supported by BLA but should also not be
 967          * sent via the mesh.
 968          */
 969         if (vlan_depth > 1)
 970                 return 1;
 971
 972         /* check if it is a claim frame. */
 973         ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
 974                                        ethhdr);
 975         if (ret == 1)
 976                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
 977                            "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
 978                            ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src,
 979                            hw_dst);
 980
 981         if (ret < 2)
 982                 return ret;
 983
 984         /* become a backbone gw ourselves on this vlan if not happened yet */
 985         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
 986
 987         /* check for the different types of claim frames ... */
 988         switch (bla_dst->type) {
 989         case BATADV_CLAIM_TYPE_CLAIM:
 990                 if (batadv_handle_claim(bat_priv, primary_if, hw_src,
 991                                         ethhdr->h_source, vid))
 992                         return 1;
 993                 break;
 994         case BATADV_CLAIM_TYPE_UNCLAIM:
 995                 if (batadv_handle_unclaim(bat_priv, primary_if,
 996                                           ethhdr->h_source, hw_src, vid))
 997                         return 1;
 998                 break;
 999
1000         case BATADV_CLAIM_TYPE_ANNOUNCE:
1001                 if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
1002                                            vid))
1003                         return 1;
1004                 break;
1005         case BATADV_CLAIM_TYPE_REQUEST:
1006                 if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
1007                                           vid))
1008                         return 1;
1009                 break;
1010         }
1011
1012         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1013                    "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",
1014                    ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src, hw_dst);
1015         return 1;
1016 }
1017
1018 /* Check when we last heard from other nodes, and remove them in case of
1019  * a time out, or clean all backbone gws if now is set.
1020  */
1021 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
1022 {
1023         struct batadv_bla_backbone_gw *backbone_gw;
1024         struct hlist_node *node_tmp;
1025         struct hlist_head *head;
1026         struct batadv_hashtable *hash;
1027         spinlock_t *list_lock;  /* protects write access to the hash lists */
1028         int i;
1029
1030         hash = bat_priv->bla.backbone_hash;
1031         if (!hash)
1032                 return;
1033
1034         for (i = 0; i < hash->size; i++) {
1035                 head = &hash->table[i];
1036                 list_lock = &hash->list_locks[i];
1037
1038                 spin_lock_bh(list_lock);
1039                 hlist_for_each_entry_safe(backbone_gw, node_tmp,
1040                                           head, hash_entry) {
1041                         if (now)
1042                                 goto purge_now;
1043                         if (!batadv_has_timed_out(backbone_gw->lasttime,
1044                                                   BATADV_BLA_BACKBONE_TIMEOUT))
1045                                 continue;
1046
1047                         batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
1048                                    "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
1049                                    backbone_gw->orig);
1050
1051 purge_now:
1052                         /* don't wait for the pending request anymore */
1053                         if (atomic_read(&backbone_gw->request_sent))
1054                                 atomic_dec(&bat_priv->bla.num_requests);
1055
1056                         batadv_bla_del_backbone_claims(backbone_gw);
1057
1058                         hlist_del_rcu(&backbone_gw->hash_entry);
1059                         batadv_backbone_gw_free_ref(backbone_gw);
1060                 }
1061                 spin_unlock_bh(list_lock);
1062         }
1063 }
1064
1065 /**
1066  * batadv_bla_purge_claims
1067  * @bat_priv: the bat priv with all the soft interface information
1068  * @primary_if: the selected primary interface, may be NULL if now is set
1069  * @now: whether the whole hash shall be wiped now
1070  *
1071  * Check when we heard last time from our own claims, and remove them in case of
1072  * a time out, or clean all claims if now is set
1073  */
1074 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
1075                                     struct batadv_hard_iface *primary_if,
1076                                     int now)
1077 {
1078         struct batadv_bla_claim *claim;
1079         struct hlist_head *head;
1080         struct batadv_hashtable *hash;
1081         int i;
1082
1083         hash = bat_priv->bla.claim_hash;
1084         if (!hash)
1085                 return;
1086
1087         for (i = 0; i < hash->size; i++) {
1088                 head = &hash->table[i];
1089
1090                 rcu_read_lock();
1091                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1092                         if (now)
1093                                 goto purge_now;
1094                         if (!batadv_compare_eth(claim->backbone_gw->orig,
1095                                                 primary_if->net_dev->dev_addr))
1096                                 continue;
1097                         if (!batadv_has_timed_out(claim->lasttime,
1098                                                   BATADV_BLA_CLAIM_TIMEOUT))
1099                                 continue;
1100
1101                         batadv_dbg(BATADV_DBG_BLA, bat_priv,
1102                                    "bla_purge_claims(): %pM, vid %d, time out\n",
1103                                    claim->addr, claim->vid);
1104
1105 purge_now:
1106                         batadv_handle_unclaim(bat_priv, primary_if,
1107                                               claim->backbone_gw->orig,
1108                                               claim->addr, claim->vid);
1109                 }
1110                 rcu_read_unlock();
1111         }
1112 }
1113
1114 /**
1115  * batadv_bla_update_orig_address
1116  * @bat_priv: the bat priv with all the soft interface information
1117  * @primary_if: the new selected primary_if
1118  * @oldif: the old primary interface, may be NULL
1119  *
1120  * Update the backbone gateways when the own orig address changes.
1121  */
1122 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1123                                     struct batadv_hard_iface *primary_if,
1124                                     struct batadv_hard_iface *oldif)
1125 {
1126         struct batadv_bla_backbone_gw *backbone_gw;
1127         struct hlist_head *head;
1128         struct batadv_hashtable *hash;
1129         __be16 group;
1130         int i;
1131
1132         /* reset bridge loop avoidance group id */
1133         group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1134         bat_priv->bla.claim_dest.group = group;
1135
1136         /* purge everything when bridge loop avoidance is turned off */
1137         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1138                 oldif = NULL;
1139
1140         if (!oldif) {
1141                 batadv_bla_purge_claims(bat_priv, NULL, 1);
1142                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1143                 return;
1144         }
1145
1146         hash = bat_priv->bla.backbone_hash;
1147         if (!hash)
1148                 return;
1149
1150         for (i = 0; i < hash->size; i++) {
1151                 head = &hash->table[i];
1152
1153                 rcu_read_lock();
1154                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1155                         /* own orig still holds the old value. */
1156                         if (!batadv_compare_eth(backbone_gw->orig,
1157                                                 oldif->net_dev->dev_addr))
1158                                 continue;
1159
1160                         ether_addr_copy(backbone_gw->orig,
1161                                         primary_if->net_dev->dev_addr);
1162                         /* send an announce frame so others will ask for our
1163                          * claims and update their tables.
1164                          */
1165                         batadv_bla_send_announce(bat_priv, backbone_gw);
1166                 }
1167                 rcu_read_unlock();
1168         }
1169 }
1170
1171 /**
1172  * batadv_bla_status_update - purge bla interfaces if necessary
1173  * @net_dev: the soft interface net device
1174  */
1175 void batadv_bla_status_update(struct net_device *net_dev)
1176 {
1177         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1178         struct batadv_hard_iface *primary_if;
1179
1180         primary_if = batadv_primary_if_get_selected(bat_priv);
1181         if (!primary_if)
1182                 return;
1183
1184         /* this function already purges everything when bla is disabled,
1185          * so just call that one.
1186          */
1187         batadv_bla_update_orig_address(bat_priv, primary_if, primary_if);
1188         batadv_hardif_free_ref(primary_if);
1189 }
1190
1191 /* periodic work to do:
1192  *  * purge structures when they are too old
1193  *  * send announcements
1194  */
1195 static void batadv_bla_periodic_work(struct work_struct *work)
1196 {
1197         struct delayed_work *delayed_work;
1198         struct batadv_priv *bat_priv;
1199         struct batadv_priv_bla *priv_bla;
1200         struct hlist_head *head;
1201         struct batadv_bla_backbone_gw *backbone_gw;
1202         struct batadv_hashtable *hash;
1203         struct batadv_hard_iface *primary_if;
1204         int i;
1205
1206         delayed_work = container_of(work, struct delayed_work, work);
1207         priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1208         bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1209         primary_if = batadv_primary_if_get_selected(bat_priv);
1210         if (!primary_if)
1211                 goto out;
1212
1213         batadv_bla_purge_claims(bat_priv, primary_if, 0);
1214         batadv_bla_purge_backbone_gw(bat_priv, 0);
1215
1216         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1217                 goto out;
1218
1219         hash = bat_priv->bla.backbone_hash;
1220         if (!hash)
1221                 goto out;
1222
1223         for (i = 0; i < hash->size; i++) {
1224                 head = &hash->table[i];
1225
1226                 rcu_read_lock();
1227                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1228                         if (!batadv_compare_eth(backbone_gw->orig,
1229                                                 primary_if->net_dev->dev_addr))
1230                                 continue;
1231
1232                         backbone_gw->lasttime = jiffies;
1233
1234                         batadv_bla_send_announce(bat_priv, backbone_gw);
1235
1236                         /* request_sent is only set after creation to avoid
1237                          * problems when we are not yet known as backbone gw
1238                          * in the backbone.
1239                          *
1240                          * We can reset this now after we waited some periods
1241                          * to give bridge forward delays and bla group forming
1242                          * some grace time.
1243                          */
1244
1245                         if (atomic_read(&backbone_gw->request_sent) == 0)
1246                                 continue;
1247
1248                         if (!atomic_dec_and_test(&backbone_gw->wait_periods))
1249                                 continue;
1250
1251                         atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
1252                         atomic_set(&backbone_gw->request_sent, 0);
1253                 }
1254                 rcu_read_unlock();
1255         }
1256 out:
1257         if (primary_if)
1258                 batadv_hardif_free_ref(primary_if);
1259
1260         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1261                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1262 }
1263
1264 /* The hash for claim and backbone hash receive the same key because they
1265  * are getting initialized by hash_new with the same key. Reinitializing
1266  * them with to different keys to allow nested locking without generating
1267  * lockdep warnings
1268  */
1269 static struct lock_class_key batadv_claim_hash_lock_class_key;
1270 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1271
1272 /* initialize all bla structures */
1273 int batadv_bla_init(struct batadv_priv *bat_priv)
1274 {
1275         int i;
1276         u8 claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1277         struct batadv_hard_iface *primary_if;
1278         u16 crc;
1279         unsigned long entrytime;
1280
1281         spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1282
1283         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1284
1285         /* setting claim destination address */
1286         memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1287         bat_priv->bla.claim_dest.type = 0;
1288         primary_if = batadv_primary_if_get_selected(bat_priv);
1289         if (primary_if) {
1290                 crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1291                 bat_priv->bla.claim_dest.group = htons(crc);
1292                 batadv_hardif_free_ref(primary_if);
1293         } else {
1294                 bat_priv->bla.claim_dest.group = 0; /* will be set later */
1295         }
1296
1297         /* initialize the duplicate list */
1298         entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1299         for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1300                 bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1301         bat_priv->bla.bcast_duplist_curr = 0;
1302
1303         if (bat_priv->bla.claim_hash)
1304                 return 0;
1305
1306         bat_priv->bla.claim_hash = batadv_hash_new(128);
1307         bat_priv->bla.backbone_hash = batadv_hash_new(32);
1308
1309         if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
1310                 return -ENOMEM;
1311
1312         batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1313                                    &batadv_claim_hash_lock_class_key);
1314         batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1315                                    &batadv_backbone_hash_lock_class_key);
1316
1317         batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1318
1319         INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1320
1321         queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1322                            msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1323         return 0;
1324 }
1325
1326 /**
1327  * batadv_bla_check_bcast_duplist
1328  * @bat_priv: the bat priv with all the soft interface information
1329  * @skb: contains the bcast_packet to be checked
1330  *
1331  * check if it is on our broadcast list. Another gateway might
1332  * have sent the same packet because it is connected to the same backbone,
1333  * so we have to remove this duplicate.
1334  *
1335  * This is performed by checking the CRC, which will tell us
1336  * with a good chance that it is the same packet. If it is furthermore
1337  * sent by another host, drop it. We allow equal packets from
1338  * the same host however as this might be intended.
1339  */
1340 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1341                                    struct sk_buff *skb)
1342 {
1343         int i, curr, ret = 0;
1344         __be32 crc;
1345         struct batadv_bcast_packet *bcast_packet;
1346         struct batadv_bcast_duplist_entry *entry;
1347
1348         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1349
1350         /* calculate the crc ... */
1351         crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
1352
1353         spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1354
1355         for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1356                 curr = (bat_priv->bla.bcast_duplist_curr + i);
1357                 curr %= BATADV_DUPLIST_SIZE;
1358                 entry = &bat_priv->bla.bcast_duplist[curr];
1359
1360                 /* we can stop searching if the entry is too old ;
1361                  * later entries will be even older
1362                  */
1363                 if (batadv_has_timed_out(entry->entrytime,
1364                                          BATADV_DUPLIST_TIMEOUT))
1365                         break;
1366
1367                 if (entry->crc != crc)
1368                         continue;
1369
1370                 if (batadv_compare_eth(entry->orig, bcast_packet->orig))
1371                         continue;
1372
1373                 /* this entry seems to match: same crc, not too old,
1374                  * and from another gw. therefore return 1 to forbid it.
1375                  */
1376                 ret = 1;
1377                 goto out;
1378         }
1379         /* not found, add a new entry (overwrite the oldest entry)
1380          * and allow it, its the first occurrence.
1381          */
1382         curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1383         curr %= BATADV_DUPLIST_SIZE;
1384         entry = &bat_priv->bla.bcast_duplist[curr];
1385         entry->crc = crc;
1386         entry->entrytime = jiffies;
1387         ether_addr_copy(entry->orig, bcast_packet->orig);
1388         bat_priv->bla.bcast_duplist_curr = curr;
1389
1390 out:
1391         spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1392
1393         return ret;
1394 }
1395
1396 /**
1397  * batadv_bla_is_backbone_gw_orig
1398  * @bat_priv: the bat priv with all the soft interface information
1399  * @orig: originator mac address
1400  * @vid: VLAN identifier
1401  *
1402  * Check if the originator is a gateway for the VLAN identified by vid.
1403  *
1404  * Returns true if orig is a backbone for this vid, false otherwise.
1405  */
1406 bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, u8 *orig,
1407                                     unsigned short vid)
1408 {
1409         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1410         struct hlist_head *head;
1411         struct batadv_bla_backbone_gw *backbone_gw;
1412         int i;
1413
1414         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1415                 return false;
1416
1417         if (!hash)
1418                 return false;
1419
1420         for (i = 0; i < hash->size; i++) {
1421                 head = &hash->table[i];
1422
1423                 rcu_read_lock();
1424                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1425                         if (batadv_compare_eth(backbone_gw->orig, orig) &&
1426                             backbone_gw->vid == vid) {
1427                                 rcu_read_unlock();
1428                                 return true;
1429                         }
1430                 }
1431                 rcu_read_unlock();
1432         }
1433
1434         return false;
1435 }
1436
1437 /**
1438  * batadv_bla_is_backbone_gw
1439  * @skb: the frame to be checked
1440  * @orig_node: the orig_node of the frame
1441  * @hdr_size: maximum length of the frame
1442  *
1443  * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
1444  * if the orig_node is also a gateway on the soft interface, otherwise it
1445  * returns 0.
1446  */
1447 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
1448                               struct batadv_orig_node *orig_node, int hdr_size)
1449 {
1450         struct batadv_bla_backbone_gw *backbone_gw;
1451         unsigned short vid;
1452
1453         if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1454                 return 0;
1455
1456         /* first, find out the vid. */
1457         if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1458                 return 0;
1459
1460         vid = batadv_get_vid(skb, hdr_size);
1461
1462         /* see if this originator is a backbone gw for this VLAN */
1463         backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1464                                                 orig_node->orig, vid);
1465         if (!backbone_gw)
1466                 return 0;
1467
1468         batadv_backbone_gw_free_ref(backbone_gw);
1469         return 1;
1470 }
1471
1472 /* free all bla structures (for softinterface free or module unload) */
1473 void batadv_bla_free(struct batadv_priv *bat_priv)
1474 {
1475         struct batadv_hard_iface *primary_if;
1476
1477         cancel_delayed_work_sync(&bat_priv->bla.work);
1478         primary_if = batadv_primary_if_get_selected(bat_priv);
1479
1480         if (bat_priv->bla.claim_hash) {
1481                 batadv_bla_purge_claims(bat_priv, primary_if, 1);
1482                 batadv_hash_destroy(bat_priv->bla.claim_hash);
1483                 bat_priv->bla.claim_hash = NULL;
1484         }
1485         if (bat_priv->bla.backbone_hash) {
1486                 batadv_bla_purge_backbone_gw(bat_priv, 1);
1487                 batadv_hash_destroy(bat_priv->bla.backbone_hash);
1488                 bat_priv->bla.backbone_hash = NULL;
1489         }
1490         if (primary_if)
1491                 batadv_hardif_free_ref(primary_if);
1492 }
1493
1494 /**
1495  * batadv_bla_rx
1496  * @bat_priv: the bat priv with all the soft interface information
1497  * @skb: the frame to be checked
1498  * @vid: the VLAN ID of the frame
1499  * @is_bcast: the packet came in a broadcast packet type.
1500  *
1501  * bla_rx avoidance checks if:
1502  *  * we have to race for a claim
1503  *  * if the frame is allowed on the LAN
1504  *
1505  * in these cases, the skb is further handled by this function and
1506  * returns 1, otherwise it returns 0 and the caller shall further
1507  * process the skb.
1508  */
1509 int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1510                   unsigned short vid, bool is_bcast)
1511 {
1512         struct ethhdr *ethhdr;
1513         struct batadv_bla_claim search_claim, *claim = NULL;
1514         struct batadv_hard_iface *primary_if;
1515         int ret;
1516
1517         ethhdr = eth_hdr(skb);
1518
1519         primary_if = batadv_primary_if_get_selected(bat_priv);
1520         if (!primary_if)
1521                 goto handled;
1522
1523         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1524                 goto allow;
1525
1526         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1527                 /* don't allow broadcasts while requests are in flight */
1528                 if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
1529                         goto handled;
1530
1531         ether_addr_copy(search_claim.addr, ethhdr->h_source);
1532         search_claim.vid = vid;
1533         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1534
1535         if (!claim) {
1536                 /* possible optimization: race for a claim */
1537                 /* No claim exists yet, claim it for us!
1538                  */
1539                 batadv_handle_claim(bat_priv, primary_if,
1540                                     primary_if->net_dev->dev_addr,
1541                                     ethhdr->h_source, vid);
1542                 goto allow;
1543         }
1544
1545         /* if it is our own claim ... */
1546         if (batadv_compare_eth(claim->backbone_gw->orig,
1547                                primary_if->net_dev->dev_addr)) {
1548                 /* ... allow it in any case */
1549                 claim->lasttime = jiffies;
1550                 goto allow;
1551         }
1552
1553         /* if it is a broadcast ... */
1554         if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
1555                 /* ... drop it. the responsible gateway is in charge.
1556                  *
1557                  * We need to check is_bcast because with the gateway
1558                  * feature, broadcasts (like DHCP requests) may be sent
1559                  * using a unicast packet type.
1560                  */
1561                 goto handled;
1562         } else {
1563                 /* seems the client considers us as its best gateway.
1564                  * send a claim and update the claim table
1565                  * immediately.
1566                  */
1567                 batadv_handle_claim(bat_priv, primary_if,
1568                                     primary_if->net_dev->dev_addr,
1569                                     ethhdr->h_source, vid);
1570                 goto allow;
1571         }
1572 allow:
1573         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1574         ret = 0;
1575         goto out;
1576
1577 handled:
1578         kfree_skb(skb);
1579         ret = 1;
1580
1581 out:
1582         if (primary_if)
1583                 batadv_hardif_free_ref(primary_if);
1584         if (claim)
1585                 batadv_claim_free_ref(claim);
1586         return ret;
1587 }
1588
1589 /**
1590  * batadv_bla_tx
1591  * @bat_priv: the bat priv with all the soft interface information
1592  * @skb: the frame to be checked
1593  * @vid: the VLAN ID of the frame
1594  *
1595  * bla_tx checks if:
1596  *  * a claim was received which has to be processed
1597  *  * the frame is allowed on the mesh
1598  *
1599  * in these cases, the skb is further handled by this function and
1600  * returns 1, otherwise it returns 0 and the caller shall further
1601  * process the skb.
1602  *
1603  * This call might reallocate skb data.
1604  */
1605 int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1606                   unsigned short vid)
1607 {
1608         struct ethhdr *ethhdr;
1609         struct batadv_bla_claim search_claim, *claim = NULL;
1610         struct batadv_hard_iface *primary_if;
1611         int ret = 0;
1612
1613         primary_if = batadv_primary_if_get_selected(bat_priv);
1614         if (!primary_if)
1615                 goto out;
1616
1617         if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1618                 goto allow;
1619
1620         if (batadv_bla_process_claim(bat_priv, primary_if, skb))
1621                 goto handled;
1622
1623         ethhdr = eth_hdr(skb);
1624
1625         if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1626                 /* don't allow broadcasts while requests are in flight */
1627                 if (is_multicast_ether_addr(ethhdr->h_dest))
1628                         goto handled;
1629
1630         ether_addr_copy(search_claim.addr, ethhdr->h_source);
1631         search_claim.vid = vid;
1632
1633         claim = batadv_claim_hash_find(bat_priv, &search_claim);
1634
1635         /* if no claim exists, allow it. */
1636         if (!claim)
1637                 goto allow;
1638
1639         /* check if we are responsible. */
1640         if (batadv_compare_eth(claim->backbone_gw->orig,
1641                                primary_if->net_dev->dev_addr)) {
1642                 /* if yes, the client has roamed and we have
1643                  * to unclaim it.
1644                  */
1645                 batadv_handle_unclaim(bat_priv, primary_if,
1646                                       primary_if->net_dev->dev_addr,
1647                                       ethhdr->h_source, vid);
1648                 goto allow;
1649         }
1650
1651         /* check if it is a multicast/broadcast frame */
1652         if (is_multicast_ether_addr(ethhdr->h_dest)) {
1653                 /* drop it. the responsible gateway has forwarded it into
1654                  * the backbone network.
1655                  */
1656                 goto handled;
1657         } else {
1658                 /* we must allow it. at least if we are
1659                  * responsible for the DESTINATION.
1660                  */
1661                 goto allow;
1662         }
1663 allow:
1664         batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1665         ret = 0;
1666         goto out;
1667 handled:
1668         ret = 1;
1669 out:
1670         if (primary_if)
1671                 batadv_hardif_free_ref(primary_if);
1672         if (claim)
1673                 batadv_claim_free_ref(claim);
1674         return ret;
1675 }
1676
1677 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
1678 {
1679         struct net_device *net_dev = (struct net_device *)seq->private;
1680         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1681         struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
1682         struct batadv_bla_claim *claim;
1683         struct batadv_hard_iface *primary_if;
1684         struct hlist_head *head;
1685         u16 backbone_crc;
1686         u32 i;
1687         bool is_own;
1688         u8 *primary_addr;
1689
1690         primary_if = batadv_seq_print_text_primary_if_get(seq);
1691         if (!primary_if)
1692                 goto out;
1693
1694         primary_addr = primary_if->net_dev->dev_addr;
1695         seq_printf(seq,
1696                    "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
1697                    net_dev->name, primary_addr,
1698                    ntohs(bat_priv->bla.claim_dest.group));
1699         seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-6s)\n",
1700                    "Client", "VID", "Originator", "CRC");
1701         for (i = 0; i < hash->size; i++) {
1702                 head = &hash->table[i];
1703
1704                 rcu_read_lock();
1705                 hlist_for_each_entry_rcu(claim, head, hash_entry) {
1706                         is_own = batadv_compare_eth(claim->backbone_gw->orig,
1707                                                     primary_addr);
1708
1709                         spin_lock_bh(&claim->backbone_gw->crc_lock);
1710                         backbone_crc = claim->backbone_gw->crc;
1711                         spin_unlock_bh(&claim->backbone_gw->crc_lock);
1712                         seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n",
1713                                    claim->addr, BATADV_PRINT_VID(claim->vid),
1714                                    claim->backbone_gw->orig,
1715                                    (is_own ? 'x' : ' '),
1716                                    backbone_crc);
1717                 }
1718                 rcu_read_unlock();
1719         }
1720 out:
1721         if (primary_if)
1722                 batadv_hardif_free_ref(primary_if);
1723         return 0;
1724 }
1725
1726 int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
1727 {
1728         struct net_device *net_dev = (struct net_device *)seq->private;
1729         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1730         struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1731         struct batadv_bla_backbone_gw *backbone_gw;
1732         struct batadv_hard_iface *primary_if;
1733         struct hlist_head *head;
1734         int secs, msecs;
1735         u16 backbone_crc;
1736         u32 i;
1737         bool is_own;
1738         u8 *primary_addr;
1739
1740         primary_if = batadv_seq_print_text_primary_if_get(seq);
1741         if (!primary_if)
1742                 goto out;
1743
1744         primary_addr = primary_if->net_dev->dev_addr;
1745         seq_printf(seq,
1746                    "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
1747                    net_dev->name, primary_addr,
1748                    ntohs(bat_priv->bla.claim_dest.group));
1749         seq_printf(seq, "   %-17s    %-5s %-9s (%-6s)\n",
1750                    "Originator", "VID", "last seen", "CRC");
1751         for (i = 0; i < hash->size; i++) {
1752                 head = &hash->table[i];
1753
1754                 rcu_read_lock();
1755                 hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1756                         msecs = jiffies_to_msecs(jiffies -
1757                                                  backbone_gw->lasttime);
1758                         secs = msecs / 1000;
1759                         msecs = msecs % 1000;
1760
1761                         is_own = batadv_compare_eth(backbone_gw->orig,
1762                                                     primary_addr);
1763                         if (is_own)
1764                                 continue;
1765
1766                         spin_lock_bh(&backbone_gw->crc_lock);
1767                         backbone_crc = backbone_gw->crc;
1768                         spin_unlock_bh(&backbone_gw->crc_lock);
1769
1770                         seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n",
1771                                    backbone_gw->orig,
1772                                    BATADV_PRINT_VID(backbone_gw->vid), secs,
1773                                    msecs, backbone_crc);
1774                 }
1775                 rcu_read_unlock();
1776         }
1777 out:
1778         if (primary_if)
1779                 batadv_hardif_free_ref(primary_if);
1780         return 0;
1781 }