net/mac80211/mesh_pathtbl.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/etherdevice.h>
  11 #include <linux/list.h>
  12 #include <linux/random.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/string.h>
  16 #include <net/mac80211.h>
  17 #include "wme.h"
  18 #include "ieee80211_i.h"
  19 #include "mesh.h"
  20
  21 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  22 #define INIT_PATHS_SIZE_ORDER   2
  23
  24 /* Keep the mean chain length below this constant */
  25 #define MEAN_CHAIN_LEN          2
  26
  27 static inline bool mpath_expired(struct mesh_path *mpath)
  28 {
  29         return (mpath->flags & MESH_PATH_ACTIVE) &&
  30                time_after(jiffies, mpath->exp_time) &&
  31                !(mpath->flags & MESH_PATH_FIXED);
  32 }
  33
  34 struct mpath_node {
  35         struct hlist_node list;
  36         struct rcu_head rcu;
  37         /* This indirection allows two different tables to point to the same
  38          * mesh_path structure, useful when resizing
  39          */
  40         struct mesh_path *mpath;
  41 };
  42
  43 static struct mesh_table __rcu *mesh_paths;
  44 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  45
  46 int mesh_paths_generation;
  47
  48 /* This lock will have the grow table function as writer and add / delete nodes
  49  * as readers. RCU provides sufficient protection only when reading the table
  50  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  51  * the read lock or we risk operating on an old table.  The write lock is only
  52  * needed when modifying the number of buckets a table.
  53  */
  54 static DEFINE_RWLOCK(pathtbl_resize_lock);
  55
  56
  57 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  58 {
  59         return rcu_dereference_protected(mesh_paths,
  60                 lockdep_is_held(&pathtbl_resize_lock));
  61 }
  62
  63 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  64 {
  65         return rcu_dereference_protected(mpp_paths,
  66                 lockdep_is_held(&pathtbl_resize_lock));
  67 }
  68
  69 /*
  70  * CAREFUL -- "tbl" must not be an expression,
  71  * in particular not an rcu_dereference(), since
  72  * it's used twice. So it is illegal to do
  73  *      for_each_mesh_entry(rcu_dereference(...), ...)
  74  */
  75 #define for_each_mesh_entry(tbl, node, i) \
  76         for (i = 0; i <= tbl->hash_mask; i++) \
  77                 hlist_for_each_entry_rcu(node, &tbl->hash_buckets[i], list)
  78
  79
  80 static struct mesh_table *mesh_table_alloc(int size_order)
  81 {
  82         int i;
  83         struct mesh_table *newtbl;
  84
  85         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  86         if (!newtbl)
  87                 return NULL;
  88
  89         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  90                         (1 << size_order), GFP_ATOMIC);
  91
  92         if (!newtbl->hash_buckets) {
  93                 kfree(newtbl);
  94                 return NULL;
  95         }
  96
  97         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  98                         (1 << size_order), GFP_ATOMIC);
  99         if (!newtbl->hashwlock) {
 100                 kfree(newtbl->hash_buckets);
 101                 kfree(newtbl);
 102                 return NULL;
 103         }
 104
 105         newtbl->size_order = size_order;
 106         newtbl->hash_mask = (1 << size_order) - 1;
 107         atomic_set(&newtbl->entries,  0);
 108         get_random_bytes(&newtbl->hash_rnd,
 109                         sizeof(newtbl->hash_rnd));
 110         for (i = 0; i <= newtbl->hash_mask; i++)
 111                 spin_lock_init(&newtbl->hashwlock[i]);
 112         spin_lock_init(&newtbl->gates_lock);
 113
 114         return newtbl;
 115 }
 116
 117 static void __mesh_table_free(struct mesh_table *tbl)
 118 {
 119         kfree(tbl->hash_buckets);
 120         kfree(tbl->hashwlock);
 121         kfree(tbl);
 122 }
 123
 124 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 125 {
 126         struct hlist_head *mesh_hash;
 127         struct hlist_node *p, *q;
 128         struct mpath_node *gate;
 129         int i;
 130
 131         mesh_hash = tbl->hash_buckets;
 132         for (i = 0; i <= tbl->hash_mask; i++) {
 133                 spin_lock_bh(&tbl->hashwlock[i]);
 134                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 135                         tbl->free_node(p, free_leafs);
 136                         atomic_dec(&tbl->entries);
 137                 }
 138                 spin_unlock_bh(&tbl->hashwlock[i]);
 139         }
 140         if (free_leafs) {
 141                 spin_lock_bh(&tbl->gates_lock);
 142                 hlist_for_each_entry_safe(gate, q,
 143                                          tbl->known_gates, list) {
 144                         hlist_del(&gate->list);
 145                         kfree(gate);
 146                 }
 147                 kfree(tbl->known_gates);
 148                 spin_unlock_bh(&tbl->gates_lock);
 149         }
 150
 151         __mesh_table_free(tbl);
 152 }
 153
 154 static int mesh_table_grow(struct mesh_table *oldtbl,
 155                            struct mesh_table *newtbl)
 156 {
 157         struct hlist_head *oldhash;
 158         struct hlist_node *p, *q;
 159         int i;
 160
 161         if (atomic_read(&oldtbl->entries)
 162                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 163                 return -EAGAIN;
 164
 165         newtbl->free_node = oldtbl->free_node;
 166         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 167         newtbl->copy_node = oldtbl->copy_node;
 168         newtbl->known_gates = oldtbl->known_gates;
 169         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 170
 171         oldhash = oldtbl->hash_buckets;
 172         for (i = 0; i <= oldtbl->hash_mask; i++)
 173                 hlist_for_each(p, &oldhash[i])
 174                         if (oldtbl->copy_node(p, newtbl) < 0)
 175                                 goto errcopy;
 176
 177         return 0;
 178
 179 errcopy:
 180         for (i = 0; i <= newtbl->hash_mask; i++) {
 181                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 182                         oldtbl->free_node(p, 0);
 183         }
 184         return -ENOMEM;
 185 }
 186
 187 static u32 mesh_table_hash(const u8 *addr, struct ieee80211_sub_if_data *sdata,
 188                            struct mesh_table *tbl)
 189 {
 190         /* Use last four bytes of hw addr and interface index as hash index */
 191         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex,
 192                             tbl->hash_rnd) & tbl->hash_mask;
 193 }
 194
 195
 196 /**
 197  *
 198  * mesh_path_assign_nexthop - update mesh path next hop
 199  *
 200  * @mpath: mesh path to update
 201  * @sta: next hop to assign
 202  *
 203  * Locking: mpath->state_lock must be held when calling this function
 204  */
 205 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 206 {
 207         struct sk_buff *skb;
 208         struct ieee80211_hdr *hdr;
 209         unsigned long flags;
 210
 211         rcu_assign_pointer(mpath->next_hop, sta);
 212
 213         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 214         skb_queue_walk(&mpath->frame_queue, skb) {
 215                 hdr = (struct ieee80211_hdr *) skb->data;
 216                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 217                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 218                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 219         }
 220
 221         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 222 }
 223
 224 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 225                              struct mesh_path *gate_mpath)
 226 {
 227         struct ieee80211_hdr *hdr;
 228         struct ieee80211s_hdr *mshdr;
 229         int mesh_hdrlen, hdrlen;
 230         char *next_hop;
 231
 232         hdr = (struct ieee80211_hdr *) skb->data;
 233         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 234         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 235
 236         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 237                 /* size of the fixed part of the mesh header */
 238                 mesh_hdrlen = 6;
 239
 240                 /* make room for the two extended addresses */
 241                 skb_push(skb, 2 * ETH_ALEN);
 242                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 243
 244                 hdr = (struct ieee80211_hdr *) skb->data;
 245
 246                 /* we preserve the previous mesh header and only add
 247                  * the new addreses */
 248                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 249                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 250                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 251                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 252         }
 253
 254         /* update next hop */
 255         hdr = (struct ieee80211_hdr *) skb->data;
 256         rcu_read_lock();
 257         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 258         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 259         rcu_read_unlock();
 260         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 261         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 262 }
 263
 264 /**
 265  *
 266  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 267  *
 268  * This function is used to transfer or copy frames from an unresolved mpath to
 269  * a gate mpath.  The function also adds the Address Extension field and
 270  * updates the next hop.
 271  *
 272  * If a frame already has an Address Extension field, only the next hop and
 273  * destination addresses are updated.
 274  *
 275  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 276  *
 277  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 278  * @from_mpath: The failed mpath
 279  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 280  * move them.
 281  */
 282 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 283                                     struct mesh_path *from_mpath,
 284                                     bool copy)
 285 {
 286         struct sk_buff *skb, *fskb, *tmp;
 287         struct sk_buff_head failq;
 288         unsigned long flags;
 289
 290         BUG_ON(gate_mpath == from_mpath);
 291         BUG_ON(!gate_mpath->next_hop);
 292
 293         __skb_queue_head_init(&failq);
 294
 295         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 296         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 297         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 298
 299         skb_queue_walk_safe(&failq, fskb, tmp) {
 300                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 301                                   MESH_FRAME_QUEUE_LEN) {
 302                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 303                         break;
 304                 }
 305
 306                 skb = skb_copy(fskb, GFP_ATOMIC);
 307                 if (WARN_ON(!skb))
 308                         break;
 309
 310                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 311                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 312
 313                 if (copy)
 314                         continue;
 315
 316                 __skb_unlink(fskb, &failq);
 317                 kfree_skb(fskb);
 318         }
 319
 320         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 321                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 322
 323         if (!copy)
 324                 return;
 325
 326         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 327         skb_queue_splice(&failq, &from_mpath->frame_queue);
 328         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 329 }
 330
 331
 332 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 333                                       struct ieee80211_sub_if_data *sdata)
 334 {
 335         struct mesh_path *mpath;
 336         struct hlist_head *bucket;
 337         struct mpath_node *node;
 338
 339         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 340         hlist_for_each_entry_rcu(node, bucket, list) {
 341                 mpath = node->mpath;
 342                 if (mpath->sdata == sdata &&
 343                     ether_addr_equal(dst, mpath->dst)) {
 344                         if (mpath_expired(mpath)) {
 345                                 spin_lock_bh(&mpath->state_lock);
 346                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 347                                 spin_unlock_bh(&mpath->state_lock);
 348                         }
 349                         return mpath;
 350                 }
 351         }
 352         return NULL;
 353 }
 354
 355 /**
 356  * mesh_path_lookup - look up a path in the mesh path table
 357  * @sdata: local subif
 358  * @dst: hardware address (ETH_ALEN length) of destination
 359  *
 360  * Returns: pointer to the mesh path structure, or NULL if not found
 361  *
 362  * Locking: must be called within a read rcu section.
 363  */
 364 struct mesh_path *
 365 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 366 {
 367         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 368 }
 369
 370 struct mesh_path *
 371 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 372 {
 373         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 374 }
 375
 376
 377 /**
 378  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 379  * @idx: index
 380  * @sdata: local subif, or NULL for all entries
 381  *
 382  * Returns: pointer to the mesh path structure, or NULL if not found.
 383  *
 384  * Locking: must be called within a read rcu section.
 385  */
 386 struct mesh_path *
 387 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 388 {
 389         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 390         struct mpath_node *node;
 391         int i;
 392         int j = 0;
 393
 394         for_each_mesh_entry(tbl, node, i) {
 395                 if (sdata && node->mpath->sdata != sdata)
 396                         continue;
 397                 if (j++ == idx) {
 398                         if (mpath_expired(node->mpath)) {
 399                                 spin_lock_bh(&node->mpath->state_lock);
 400                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 401                                 spin_unlock_bh(&node->mpath->state_lock);
 402                         }
 403                         return node->mpath;
 404                 }
 405         }
 406
 407         return NULL;
 408 }
 409
 410 /**
 411  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 412  * @mpath: gate path to add to table
 413  */
 414 int mesh_path_add_gate(struct mesh_path *mpath)
 415 {
 416         struct mesh_table *tbl;
 417         struct mpath_node *gate, *new_gate;
 418         int err;
 419
 420         rcu_read_lock();
 421         tbl = rcu_dereference(mesh_paths);
 422
 423         hlist_for_each_entry_rcu(gate, tbl->known_gates, list)
 424                 if (gate->mpath == mpath) {
 425                         err = -EEXIST;
 426                         goto err_rcu;
 427                 }
 428
 429         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 430         if (!new_gate) {
 431                 err = -ENOMEM;
 432                 goto err_rcu;
 433         }
 434
 435         mpath->is_gate = true;
 436         mpath->sdata->u.mesh.num_gates++;
 437         new_gate->mpath = mpath;
 438         spin_lock_bh(&tbl->gates_lock);
 439         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 440         spin_unlock_bh(&tbl->gates_lock);
 441         mpath_dbg(mpath->sdata,
 442                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 443                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 444         err = 0;
 445 err_rcu:
 446         rcu_read_unlock();
 447         return err;
 448 }
 449
 450 /**
 451  * mesh_gate_del - remove a mesh gate from the list of known gates
 452  * @tbl: table which holds our list of known gates
 453  * @mpath: gate mpath
 454  *
 455  * Locking: must be called inside rcu_read_lock() section
 456  */
 457 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 458 {
 459         struct mpath_node *gate;
 460         struct hlist_node *q;
 461
 462         hlist_for_each_entry_safe(gate, q, tbl->known_gates, list) {
 463                 if (gate->mpath != mpath)
 464                         continue;
 465                 spin_lock_bh(&tbl->gates_lock);
 466                 hlist_del_rcu(&gate->list);
 467                 kfree_rcu(gate, rcu);
 468                 spin_unlock_bh(&tbl->gates_lock);
 469                 mpath->sdata->u.mesh.num_gates--;
 470                 mpath->is_gate = false;
 471                 mpath_dbg(mpath->sdata,
 472                           "Mesh path: Deleted gate: %pM. %d known gates\n",
 473                           mpath->dst, mpath->sdata->u.mesh.num_gates);
 474                 break;
 475         }
 476 }
 477
 478 /**
 479  * mesh_gate_num - number of gates known to this interface
 480  * @sdata: subif data
 481  */
 482 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 483 {
 484         return sdata->u.mesh.num_gates;
 485 }
 486
 487 /**
 488  * mesh_path_add - allocate and add a new path to the mesh path table
 489  * @dst: destination address of the path (ETH_ALEN length)
 490  * @sdata: local subif
 491  *
 492  * Returns: 0 on success
 493  *
 494  * State: the initial state of the new path is set to 0
 495  */
 496 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 497                                 const u8 *dst)
 498 {
 499         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 500         struct ieee80211_local *local = sdata->local;
 501         struct mesh_table *tbl;
 502         struct mesh_path *mpath, *new_mpath;
 503         struct mpath_node *node, *new_node;
 504         struct hlist_head *bucket;
 505         int grow = 0;
 506         int err;
 507         u32 hash_idx;
 508
 509         if (ether_addr_equal(dst, sdata->vif.addr))
 510                 /* never add ourselves as neighbours */
 511                 return ERR_PTR(-ENOTSUPP);
 512
 513         if (is_multicast_ether_addr(dst))
 514                 return ERR_PTR(-ENOTSUPP);
 515
 516         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 517                 return ERR_PTR(-ENOSPC);
 518
 519         read_lock_bh(&pathtbl_resize_lock);
 520         tbl = resize_dereference_mesh_paths();
 521
 522         hash_idx = mesh_table_hash(dst, sdata, tbl);
 523         bucket = &tbl->hash_buckets[hash_idx];
 524
 525         spin_lock(&tbl->hashwlock[hash_idx]);
 526
 527         hlist_for_each_entry(node, bucket, list) {
 528                 mpath = node->mpath;
 529                 if (mpath->sdata == sdata &&
 530                     ether_addr_equal(dst, mpath->dst))
 531                         goto found;
 532         }
 533
 534         err = -ENOMEM;
 535         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 536         if (!new_mpath)
 537                 goto err_path_alloc;
 538
 539         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 540         if (!new_node)
 541                 goto err_node_alloc;
 542
 543         memcpy(new_mpath->dst, dst, ETH_ALEN);
 544         eth_broadcast_addr(new_mpath->rann_snd_addr);
 545         new_mpath->is_root = false;
 546         new_mpath->sdata = sdata;
 547         new_mpath->flags = 0;
 548         skb_queue_head_init(&new_mpath->frame_queue);
 549         new_node->mpath = new_mpath;
 550         new_mpath->timer.data = (unsigned long) new_mpath;
 551         new_mpath->timer.function = mesh_path_timer;
 552         new_mpath->exp_time = jiffies;
 553         spin_lock_init(&new_mpath->state_lock);
 554         init_timer(&new_mpath->timer);
 555
 556         hlist_add_head_rcu(&new_node->list, bucket);
 557         if (atomic_inc_return(&tbl->entries) >=
 558             tbl->mean_chain_len * (tbl->hash_mask + 1))
 559                 grow = 1;
 560
 561         mesh_paths_generation++;
 562
 563         if (grow) {
 564                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 565                 ieee80211_queue_work(&local->hw, &sdata->work);
 566         }
 567         mpath = new_mpath;
 568 found:
 569         spin_unlock(&tbl->hashwlock[hash_idx]);
 570         read_unlock_bh(&pathtbl_resize_lock);
 571         return mpath;
 572
 573 err_node_alloc:
 574         kfree(new_mpath);
 575 err_path_alloc:
 576         atomic_dec(&sdata->u.mesh.mpaths);
 577         spin_unlock(&tbl->hashwlock[hash_idx]);
 578         read_unlock_bh(&pathtbl_resize_lock);
 579         return ERR_PTR(err);
 580 }
 581
 582 static void mesh_table_free_rcu(struct rcu_head *rcu)
 583 {
 584         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 585
 586         mesh_table_free(tbl, false);
 587 }
 588
 589 void mesh_mpath_table_grow(void)
 590 {
 591         struct mesh_table *oldtbl, *newtbl;
 592
 593         write_lock_bh(&pathtbl_resize_lock);
 594         oldtbl = resize_dereference_mesh_paths();
 595         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 596         if (!newtbl)
 597                 goto out;
 598         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 599                 __mesh_table_free(newtbl);
 600                 goto out;
 601         }
 602         rcu_assign_pointer(mesh_paths, newtbl);
 603
 604         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 605
 606  out:
 607         write_unlock_bh(&pathtbl_resize_lock);
 608 }
 609
 610 void mesh_mpp_table_grow(void)
 611 {
 612         struct mesh_table *oldtbl, *newtbl;
 613
 614         write_lock_bh(&pathtbl_resize_lock);
 615         oldtbl = resize_dereference_mpp_paths();
 616         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 617         if (!newtbl)
 618                 goto out;
 619         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 620                 __mesh_table_free(newtbl);
 621                 goto out;
 622         }
 623         rcu_assign_pointer(mpp_paths, newtbl);
 624         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 625
 626  out:
 627         write_unlock_bh(&pathtbl_resize_lock);
 628 }
 629
 630 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 631                  const u8 *dst, const u8 *mpp)
 632 {
 633         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 634         struct ieee80211_local *local = sdata->local;
 635         struct mesh_table *tbl;
 636         struct mesh_path *mpath, *new_mpath;
 637         struct mpath_node *node, *new_node;
 638         struct hlist_head *bucket;
 639         int grow = 0;
 640         int err = 0;
 641         u32 hash_idx;
 642
 643         if (ether_addr_equal(dst, sdata->vif.addr))
 644                 /* never add ourselves as neighbours */
 645                 return -ENOTSUPP;
 646
 647         if (is_multicast_ether_addr(dst))
 648                 return -ENOTSUPP;
 649
 650         err = -ENOMEM;
 651         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 652         if (!new_mpath)
 653                 goto err_path_alloc;
 654
 655         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 656         if (!new_node)
 657                 goto err_node_alloc;
 658
 659         read_lock_bh(&pathtbl_resize_lock);
 660         memcpy(new_mpath->dst, dst, ETH_ALEN);
 661         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 662         new_mpath->sdata = sdata;
 663         new_mpath->flags = 0;
 664         skb_queue_head_init(&new_mpath->frame_queue);
 665         new_node->mpath = new_mpath;
 666         init_timer(&new_mpath->timer);
 667         new_mpath->exp_time = jiffies;
 668         spin_lock_init(&new_mpath->state_lock);
 669
 670         tbl = resize_dereference_mpp_paths();
 671
 672         hash_idx = mesh_table_hash(dst, sdata, tbl);
 673         bucket = &tbl->hash_buckets[hash_idx];
 674
 675         spin_lock(&tbl->hashwlock[hash_idx]);
 676
 677         err = -EEXIST;
 678         hlist_for_each_entry(node, bucket, list) {
 679                 mpath = node->mpath;
 680                 if (mpath->sdata == sdata &&
 681                     ether_addr_equal(dst, mpath->dst))
 682                         goto err_exists;
 683         }
 684
 685         hlist_add_head_rcu(&new_node->list, bucket);
 686         if (atomic_inc_return(&tbl->entries) >=
 687             tbl->mean_chain_len * (tbl->hash_mask + 1))
 688                 grow = 1;
 689
 690         spin_unlock(&tbl->hashwlock[hash_idx]);
 691         read_unlock_bh(&pathtbl_resize_lock);
 692         if (grow) {
 693                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 694                 ieee80211_queue_work(&local->hw, &sdata->work);
 695         }
 696         return 0;
 697
 698 err_exists:
 699         spin_unlock(&tbl->hashwlock[hash_idx]);
 700         read_unlock_bh(&pathtbl_resize_lock);
 701         kfree(new_node);
 702 err_node_alloc:
 703         kfree(new_mpath);
 704 err_path_alloc:
 705         return err;
 706 }
 707
 708
 709 /**
 710  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 711  *
 712  * @sta: broken peer link
 713  *
 714  * This function must be called from the rate control algorithm if enough
 715  * delivery errors suggest that a peer link is no longer usable.
 716  */
 717 void mesh_plink_broken(struct sta_info *sta)
 718 {
 719         struct mesh_table *tbl;
 720         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 721         struct mesh_path *mpath;
 722         struct mpath_node *node;
 723         struct ieee80211_sub_if_data *sdata = sta->sdata;
 724         int i;
 725
 726         rcu_read_lock();
 727         tbl = rcu_dereference(mesh_paths);
 728         for_each_mesh_entry(tbl, node, i) {
 729                 mpath = node->mpath;
 730                 if (rcu_dereference(mpath->next_hop) == sta &&
 731                     mpath->flags & MESH_PATH_ACTIVE &&
 732                     !(mpath->flags & MESH_PATH_FIXED)) {
 733                         spin_lock_bh(&mpath->state_lock);
 734                         mpath->flags &= ~MESH_PATH_ACTIVE;
 735                         ++mpath->sn;
 736                         spin_unlock_bh(&mpath->state_lock);
 737                         mesh_path_error_tx(sdata,
 738                                 sdata->u.mesh.mshcfg.element_ttl,
 739                                 mpath->dst, mpath->sn,
 740                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 741                 }
 742         }
 743         rcu_read_unlock();
 744 }
 745
 746 static void mesh_path_node_reclaim(struct rcu_head *rp)
 747 {
 748         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 749         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 750
 751         del_timer_sync(&node->mpath->timer);
 752         atomic_dec(&sdata->u.mesh.mpaths);
 753         kfree(node->mpath);
 754         kfree(node);
 755 }
 756
 757 /* needs to be called with the corresponding hashwlock taken */
 758 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 759 {
 760         struct mesh_path *mpath;
 761         mpath = node->mpath;
 762         spin_lock(&mpath->state_lock);
 763         mpath->flags |= MESH_PATH_RESOLVING;
 764         if (mpath->is_gate)
 765                 mesh_gate_del(tbl, mpath);
 766         hlist_del_rcu(&node->list);
 767         call_rcu(&node->rcu, mesh_path_node_reclaim);
 768         spin_unlock(&mpath->state_lock);
 769         atomic_dec(&tbl->entries);
 770 }
 771
 772 /**
 773  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 774  *
 775  * @sta: mesh peer to match
 776  *
 777  * RCU notes: this function is called when a mesh plink transitions from
 778  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 779  * allows path creation. This will happen before the sta can be freed (because
 780  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 781  * protected against the plink disappearing.
 782  */
 783 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 784 {
 785         struct mesh_table *tbl;
 786         struct mesh_path *mpath;
 787         struct mpath_node *node;
 788         int i;
 789
 790         rcu_read_lock();
 791         read_lock_bh(&pathtbl_resize_lock);
 792         tbl = resize_dereference_mesh_paths();
 793         for_each_mesh_entry(tbl, node, i) {
 794                 mpath = node->mpath;
 795                 if (rcu_dereference(mpath->next_hop) == sta) {
 796                         spin_lock(&tbl->hashwlock[i]);
 797                         __mesh_path_del(tbl, node);
 798                         spin_unlock(&tbl->hashwlock[i]);
 799                 }
 800         }
 801         read_unlock_bh(&pathtbl_resize_lock);
 802         rcu_read_unlock();
 803 }
 804
 805 static void table_flush_by_iface(struct mesh_table *tbl,
 806                                  struct ieee80211_sub_if_data *sdata)
 807 {
 808         struct mesh_path *mpath;
 809         struct mpath_node *node;
 810         int i;
 811
 812         WARN_ON(!rcu_read_lock_held());
 813         for_each_mesh_entry(tbl, node, i) {
 814                 mpath = node->mpath;
 815                 if (mpath->sdata != sdata)
 816                         continue;
 817                 spin_lock_bh(&tbl->hashwlock[i]);
 818                 __mesh_path_del(tbl, node);
 819                 spin_unlock_bh(&tbl->hashwlock[i]);
 820         }
 821 }
 822
 823 /**
 824  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 825  *
 826  * This function deletes both mesh paths as well as mesh portal paths.
 827  *
 828  * @sdata: interface data to match
 829  *
 830  */
 831 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 832 {
 833         struct mesh_table *tbl;
 834
 835         rcu_read_lock();
 836         read_lock_bh(&pathtbl_resize_lock);
 837         tbl = resize_dereference_mesh_paths();
 838         table_flush_by_iface(tbl, sdata);
 839         tbl = resize_dereference_mpp_paths();
 840         table_flush_by_iface(tbl, sdata);
 841         read_unlock_bh(&pathtbl_resize_lock);
 842         rcu_read_unlock();
 843 }
 844
 845 /**
 846  * mesh_path_del - delete a mesh path from the table
 847  *
 848  * @addr: dst address (ETH_ALEN length)
 849  * @sdata: local subif
 850  *
 851  * Returns: 0 if successful
 852  */
 853 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 854 {
 855         struct mesh_table *tbl;
 856         struct mesh_path *mpath;
 857         struct mpath_node *node;
 858         struct hlist_head *bucket;
 859         int hash_idx;
 860         int err = 0;
 861
 862         read_lock_bh(&pathtbl_resize_lock);
 863         tbl = resize_dereference_mesh_paths();
 864         hash_idx = mesh_table_hash(addr, sdata, tbl);
 865         bucket = &tbl->hash_buckets[hash_idx];
 866
 867         spin_lock(&tbl->hashwlock[hash_idx]);
 868         hlist_for_each_entry(node, bucket, list) {
 869                 mpath = node->mpath;
 870                 if (mpath->sdata == sdata &&
 871                     ether_addr_equal(addr, mpath->dst)) {
 872                         __mesh_path_del(tbl, node);
 873                         goto enddel;
 874                 }
 875         }
 876
 877         err = -ENXIO;
 878 enddel:
 879         mesh_paths_generation++;
 880         spin_unlock(&tbl->hashwlock[hash_idx]);
 881         read_unlock_bh(&pathtbl_resize_lock);
 882         return err;
 883 }
 884
 885 /**
 886  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 887  *
 888  * @mpath: mesh path to activate
 889  *
 890  * Locking: the state_lock of the mpath structure must NOT be held when calling
 891  * this function.
 892  */
 893 void mesh_path_tx_pending(struct mesh_path *mpath)
 894 {
 895         if (mpath->flags & MESH_PATH_ACTIVE)
 896                 ieee80211_add_pending_skbs(mpath->sdata->local,
 897                                 &mpath->frame_queue);
 898 }
 899
 900 /**
 901  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 902  *
 903  * @mpath: mesh path whose queue will be emptied
 904  *
 905  * If there is only one gate, the frames are transferred from the failed mpath
 906  * queue to that gate's queue.  If there are more than one gates, the frames
 907  * are copied from each gate to the next.  After frames are copied, the
 908  * mpath queues are emptied onto the transmission queue.
 909  */
 910 int mesh_path_send_to_gates(struct mesh_path *mpath)
 911 {
 912         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 913         struct mesh_table *tbl;
 914         struct mesh_path *from_mpath = mpath;
 915         struct mpath_node *gate = NULL;
 916         bool copy = false;
 917         struct hlist_head *known_gates;
 918
 919         rcu_read_lock();
 920         tbl = rcu_dereference(mesh_paths);
 921         known_gates = tbl->known_gates;
 922         rcu_read_unlock();
 923
 924         if (!known_gates)
 925                 return -EHOSTUNREACH;
 926
 927         hlist_for_each_entry_rcu(gate, known_gates, list) {
 928                 if (gate->mpath->sdata != sdata)
 929                         continue;
 930
 931                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 932                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 933                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 934                         from_mpath = gate->mpath;
 935                         copy = true;
 936                 } else {
 937                         mpath_dbg(sdata,
 938                                   "Not forwarding %p (flags %#x)\n",
 939                                   gate->mpath, gate->mpath->flags);
 940                 }
 941         }
 942
 943         hlist_for_each_entry_rcu(gate, known_gates, list)
 944                 if (gate->mpath->sdata == sdata) {
 945                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 946                         mesh_path_tx_pending(gate->mpath);
 947                 }
 948
 949         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 950 }
 951
 952 /**
 953  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 954  *
 955  * @skb: frame to discard
 956  * @sdata: network subif the frame was to be sent through
 957  *
 958  * Locking: the function must me called within a rcu_read_lock region
 959  */
 960 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 961                              struct sk_buff *skb)
 962 {
 963         kfree_skb(skb);
 964         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 965 }
 966
 967 /**
 968  * mesh_path_flush_pending - free the pending queue of a mesh path
 969  *
 970  * @mpath: mesh path whose queue has to be freed
 971  *
 972  * Locking: the function must me called within a rcu_read_lock region
 973  */
 974 void mesh_path_flush_pending(struct mesh_path *mpath)
 975 {
 976         struct sk_buff *skb;
 977
 978         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 979                 mesh_path_discard_frame(mpath->sdata, skb);
 980 }
 981
 982 /**
 983  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 984  *
 985  * @mpath: the mesh path to modify
 986  * @next_hop: the next hop to force
 987  *
 988  * Locking: this function must be called holding mpath->state_lock
 989  */
 990 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 991 {
 992         spin_lock_bh(&mpath->state_lock);
 993         mesh_path_assign_nexthop(mpath, next_hop);
 994         mpath->sn = 0xffff;
 995         mpath->metric = 0;
 996         mpath->hop_count = 0;
 997         mpath->exp_time = 0;
 998         mpath->flags |= MESH_PATH_FIXED;
 999         mesh_path_activate(mpath);
1000         spin_unlock_bh(&mpath->state_lock);
1001         mesh_path_tx_pending(mpath);
1002 }
1003
1004 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1005 {
1006         struct mesh_path *mpath;
1007         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1008         mpath = node->mpath;
1009         hlist_del_rcu(p);
1010         if (free_leafs) {
1011                 del_timer_sync(&mpath->timer);
1012                 kfree(mpath);
1013         }
1014         kfree(node);
1015 }
1016
1017 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1018 {
1019         struct mesh_path *mpath;
1020         struct mpath_node *node, *new_node;
1021         u32 hash_idx;
1022
1023         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1024         if (new_node == NULL)
1025                 return -ENOMEM;
1026
1027         node = hlist_entry(p, struct mpath_node, list);
1028         mpath = node->mpath;
1029         new_node->mpath = mpath;
1030         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1031         hlist_add_head(&new_node->list,
1032                         &newtbl->hash_buckets[hash_idx]);
1033         return 0;
1034 }
1035
1036 int mesh_pathtbl_init(void)
1037 {
1038         struct mesh_table *tbl_path, *tbl_mpp;
1039         int ret;
1040
1041         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1042         if (!tbl_path)
1043                 return -ENOMEM;
1044         tbl_path->free_node = &mesh_path_node_free;
1045         tbl_path->copy_node = &mesh_path_node_copy;
1046         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1047         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1048         if (!tbl_path->known_gates) {
1049                 ret = -ENOMEM;
1050                 goto free_path;
1051         }
1052         INIT_HLIST_HEAD(tbl_path->known_gates);
1053
1054
1055         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1056         if (!tbl_mpp) {
1057                 ret = -ENOMEM;
1058                 goto free_path;
1059         }
1060         tbl_mpp->free_node = &mesh_path_node_free;
1061         tbl_mpp->copy_node = &mesh_path_node_copy;
1062         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1063         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1064         if (!tbl_mpp->known_gates) {
1065                 ret = -ENOMEM;
1066                 goto free_mpp;
1067         }
1068         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1069
1070         /* Need no locking since this is during init */
1071         RCU_INIT_POINTER(mesh_paths, tbl_path);
1072         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1073
1074         return 0;
1075
1076 free_mpp:
1077         mesh_table_free(tbl_mpp, true);
1078 free_path:
1079         mesh_table_free(tbl_path, true);
1080         return ret;
1081 }
1082
1083 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1084 {
1085         struct mesh_table *tbl;
1086         struct mesh_path *mpath;
1087         struct mpath_node *node;
1088         int i;
1089
1090         rcu_read_lock();
1091         tbl = rcu_dereference(mesh_paths);
1092         for_each_mesh_entry(tbl, node, i) {
1093                 if (node->mpath->sdata != sdata)
1094                         continue;
1095                 mpath = node->mpath;
1096                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1097                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1098                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1099                         mesh_path_del(mpath->sdata, mpath->dst);
1100         }
1101         rcu_read_unlock();
1102 }
1103
1104 void mesh_pathtbl_unregister(void)
1105 {
1106         /* no need for locking during exit path */
1107         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1108         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1109 }