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 int mpp_paths_generation;
  48
  49 /* This lock will have the grow table function as writer and add / delete nodes
  50  * as readers. RCU provides sufficient protection only when reading the table
  51  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  52  * the read lock or we risk operating on an old table.  The write lock is only
  53  * needed when modifying the number of buckets a table.
  54  */
  55 static DEFINE_RWLOCK(pathtbl_resize_lock);
  56
  57
  58 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  59 {
  60         return rcu_dereference_protected(mesh_paths,
  61                 lockdep_is_held(&pathtbl_resize_lock));
  62 }
  63
  64 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  65 {
  66         return rcu_dereference_protected(mpp_paths,
  67                 lockdep_is_held(&pathtbl_resize_lock));
  68 }
  69
  70 /*
  71  * CAREFUL -- "tbl" must not be an expression,
  72  * in particular not an rcu_dereference(), since
  73  * it's used twice. So it is illegal to do
  74  *      for_each_mesh_entry(rcu_dereference(...), ...)
  75  */
  76 #define for_each_mesh_entry(tbl, node, i) \
  77         for (i = 0; i <= tbl->hash_mask; i++) \
  78                 hlist_for_each_entry_rcu(node, &tbl->hash_buckets[i], list)
  79
  80
  81 static struct mesh_table *mesh_table_alloc(int size_order)
  82 {
  83         int i;
  84         struct mesh_table *newtbl;
  85
  86         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  87         if (!newtbl)
  88                 return NULL;
  89
  90         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  91                         (1 << size_order), GFP_ATOMIC);
  92
  93         if (!newtbl->hash_buckets) {
  94                 kfree(newtbl);
  95                 return NULL;
  96         }
  97
  98         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  99                         (1 << size_order), GFP_ATOMIC);
 100         if (!newtbl->hashwlock) {
 101                 kfree(newtbl->hash_buckets);
 102                 kfree(newtbl);
 103                 return NULL;
 104         }
 105
 106         newtbl->size_order = size_order;
 107         newtbl->hash_mask = (1 << size_order) - 1;
 108         atomic_set(&newtbl->entries,  0);
 109         get_random_bytes(&newtbl->hash_rnd,
 110                         sizeof(newtbl->hash_rnd));
 111         for (i = 0; i <= newtbl->hash_mask; i++)
 112                 spin_lock_init(&newtbl->hashwlock[i]);
 113         spin_lock_init(&newtbl->gates_lock);
 114
 115         return newtbl;
 116 }
 117
 118 static void __mesh_table_free(struct mesh_table *tbl)
 119 {
 120         kfree(tbl->hash_buckets);
 121         kfree(tbl->hashwlock);
 122         kfree(tbl);
 123 }
 124
 125 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 126 {
 127         struct hlist_head *mesh_hash;
 128         struct hlist_node *p, *q;
 129         struct mpath_node *gate;
 130         int i;
 131
 132         mesh_hash = tbl->hash_buckets;
 133         for (i = 0; i <= tbl->hash_mask; i++) {
 134                 spin_lock_bh(&tbl->hashwlock[i]);
 135                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 136                         tbl->free_node(p, free_leafs);
 137                         atomic_dec(&tbl->entries);
 138                 }
 139                 spin_unlock_bh(&tbl->hashwlock[i]);
 140         }
 141         if (free_leafs) {
 142                 spin_lock_bh(&tbl->gates_lock);
 143                 hlist_for_each_entry_safe(gate, q,
 144                                          tbl->known_gates, list) {
 145                         hlist_del(&gate->list);
 146                         kfree(gate);
 147                 }
 148                 kfree(tbl->known_gates);
 149                 spin_unlock_bh(&tbl->gates_lock);
 150         }
 151
 152         __mesh_table_free(tbl);
 153 }
 154
 155 static int mesh_table_grow(struct mesh_table *oldtbl,
 156                            struct mesh_table *newtbl)
 157 {
 158         struct hlist_head *oldhash;
 159         struct hlist_node *p, *q;
 160         int i;
 161
 162         if (atomic_read(&oldtbl->entries)
 163                         < MEAN_CHAIN_LEN * (oldtbl->hash_mask + 1))
 164                 return -EAGAIN;
 165
 166         newtbl->free_node = oldtbl->free_node;
 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         if (WARN_ON(gate_mpath == from_mpath))
 291                 return;
 292         if (WARN_ON(!gate_mpath->next_hop))
 293                 return;
 294
 295         __skb_queue_head_init(&failq);
 296
 297         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 298         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 299         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 300
 301         skb_queue_walk_safe(&failq, fskb, tmp) {
 302                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 303                                   MESH_FRAME_QUEUE_LEN) {
 304                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 305                         break;
 306                 }
 307
 308                 skb = skb_copy(fskb, GFP_ATOMIC);
 309                 if (WARN_ON(!skb))
 310                         break;
 311
 312                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 313                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 314
 315                 if (copy)
 316                         continue;
 317
 318                 __skb_unlink(fskb, &failq);
 319                 kfree_skb(fskb);
 320         }
 321
 322         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 323                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 324
 325         if (!copy)
 326                 return;
 327
 328         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 329         skb_queue_splice(&failq, &from_mpath->frame_queue);
 330         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 331 }
 332
 333
 334 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 335                                       struct ieee80211_sub_if_data *sdata)
 336 {
 337         struct mesh_path *mpath;
 338         struct hlist_head *bucket;
 339         struct mpath_node *node;
 340
 341         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 342         hlist_for_each_entry_rcu(node, bucket, list) {
 343                 mpath = node->mpath;
 344                 if (mpath->sdata == sdata &&
 345                     ether_addr_equal(dst, mpath->dst)) {
 346                         if (mpath_expired(mpath)) {
 347                                 spin_lock_bh(&mpath->state_lock);
 348                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 349                                 spin_unlock_bh(&mpath->state_lock);
 350                         }
 351                         return mpath;
 352                 }
 353         }
 354         return NULL;
 355 }
 356
 357 /**
 358  * mesh_path_lookup - look up a path in the mesh path table
 359  * @sdata: local subif
 360  * @dst: hardware address (ETH_ALEN length) of destination
 361  *
 362  * Returns: pointer to the mesh path structure, or NULL if not found
 363  *
 364  * Locking: must be called within a read rcu section.
 365  */
 366 struct mesh_path *
 367 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 368 {
 369         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 370 }
 371
 372 struct mesh_path *
 373 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 374 {
 375         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 376 }
 377
 378
 379 /**
 380  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 381  * @idx: index
 382  * @sdata: local subif, or NULL for all entries
 383  *
 384  * Returns: pointer to the mesh path structure, or NULL if not found.
 385  *
 386  * Locking: must be called within a read rcu section.
 387  */
 388 struct mesh_path *
 389 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 390 {
 391         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 392         struct mpath_node *node;
 393         int i;
 394         int j = 0;
 395
 396         for_each_mesh_entry(tbl, node, i) {
 397                 if (sdata && node->mpath->sdata != sdata)
 398                         continue;
 399                 if (j++ == idx) {
 400                         if (mpath_expired(node->mpath)) {
 401                                 spin_lock_bh(&node->mpath->state_lock);
 402                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 403                                 spin_unlock_bh(&node->mpath->state_lock);
 404                         }
 405                         return node->mpath;
 406                 }
 407         }
 408
 409         return NULL;
 410 }
 411
 412 /**
 413  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 414  * @idx: index
 415  * @sdata: local subif, or NULL for all entries
 416  *
 417  * Returns: pointer to the proxy path structure, or NULL if not found.
 418  *
 419  * Locking: must be called within a read rcu section.
 420  */
 421 struct mesh_path *
 422 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 423 {
 424         struct mesh_table *tbl = rcu_dereference(mpp_paths);
 425         struct mpath_node *node;
 426         int i;
 427         int j = 0;
 428
 429         for_each_mesh_entry(tbl, node, i) {
 430                 if (sdata && node->mpath->sdata != sdata)
 431                         continue;
 432                 if (j++ == idx)
 433                         return node->mpath;
 434         }
 435
 436         return NULL;
 437 }
 438
 439 /**
 440  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 441  * @mpath: gate path to add to table
 442  */
 443 int mesh_path_add_gate(struct mesh_path *mpath)
 444 {
 445         struct mesh_table *tbl;
 446         struct mpath_node *gate, *new_gate;
 447         int err;
 448
 449         rcu_read_lock();
 450         tbl = rcu_dereference(mesh_paths);
 451
 452         hlist_for_each_entry_rcu(gate, tbl->known_gates, list)
 453                 if (gate->mpath == mpath) {
 454                         err = -EEXIST;
 455                         goto err_rcu;
 456                 }
 457
 458         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 459         if (!new_gate) {
 460                 err = -ENOMEM;
 461                 goto err_rcu;
 462         }
 463
 464         mpath->is_gate = true;
 465         mpath->sdata->u.mesh.num_gates++;
 466         new_gate->mpath = mpath;
 467         spin_lock_bh(&tbl->gates_lock);
 468         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 469         spin_unlock_bh(&tbl->gates_lock);
 470         mpath_dbg(mpath->sdata,
 471                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 472                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 473         err = 0;
 474 err_rcu:
 475         rcu_read_unlock();
 476         return err;
 477 }
 478
 479 /**
 480  * mesh_gate_del - remove a mesh gate from the list of known gates
 481  * @tbl: table which holds our list of known gates
 482  * @mpath: gate mpath
 483  *
 484  * Locking: must be called inside rcu_read_lock() section
 485  */
 486 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 487 {
 488         struct mpath_node *gate;
 489         struct hlist_node *q;
 490
 491         hlist_for_each_entry_safe(gate, q, tbl->known_gates, list) {
 492                 if (gate->mpath != mpath)
 493                         continue;
 494                 spin_lock_bh(&tbl->gates_lock);
 495                 hlist_del_rcu(&gate->list);
 496                 kfree_rcu(gate, rcu);
 497                 spin_unlock_bh(&tbl->gates_lock);
 498                 mpath->sdata->u.mesh.num_gates--;
 499                 mpath->is_gate = false;
 500                 mpath_dbg(mpath->sdata,
 501                           "Mesh path: Deleted gate: %pM. %d known gates\n",
 502                           mpath->dst, mpath->sdata->u.mesh.num_gates);
 503                 break;
 504         }
 505 }
 506
 507 /**
 508  * mesh_gate_num - number of gates known to this interface
 509  * @sdata: subif data
 510  */
 511 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 512 {
 513         return sdata->u.mesh.num_gates;
 514 }
 515
 516 /**
 517  * mesh_path_add - allocate and add a new path to the mesh path table
 518  * @dst: destination address of the path (ETH_ALEN length)
 519  * @sdata: local subif
 520  *
 521  * Returns: 0 on success
 522  *
 523  * State: the initial state of the new path is set to 0
 524  */
 525 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 526                                 const u8 *dst)
 527 {
 528         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 529         struct ieee80211_local *local = sdata->local;
 530         struct mesh_table *tbl;
 531         struct mesh_path *mpath, *new_mpath;
 532         struct mpath_node *node, *new_node;
 533         struct hlist_head *bucket;
 534         int grow = 0;
 535         int err;
 536         u32 hash_idx;
 537
 538         if (ether_addr_equal(dst, sdata->vif.addr))
 539                 /* never add ourselves as neighbours */
 540                 return ERR_PTR(-ENOTSUPP);
 541
 542         if (is_multicast_ether_addr(dst))
 543                 return ERR_PTR(-ENOTSUPP);
 544
 545         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 546                 return ERR_PTR(-ENOSPC);
 547
 548         read_lock_bh(&pathtbl_resize_lock);
 549         tbl = resize_dereference_mesh_paths();
 550
 551         hash_idx = mesh_table_hash(dst, sdata, tbl);
 552         bucket = &tbl->hash_buckets[hash_idx];
 553
 554         spin_lock(&tbl->hashwlock[hash_idx]);
 555
 556         hlist_for_each_entry(node, bucket, list) {
 557                 mpath = node->mpath;
 558                 if (mpath->sdata == sdata &&
 559                     ether_addr_equal(dst, mpath->dst))
 560                         goto found;
 561         }
 562
 563         err = -ENOMEM;
 564         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 565         if (!new_mpath)
 566                 goto err_path_alloc;
 567
 568         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 569         if (!new_node)
 570                 goto err_node_alloc;
 571
 572         memcpy(new_mpath->dst, dst, ETH_ALEN);
 573         eth_broadcast_addr(new_mpath->rann_snd_addr);
 574         new_mpath->is_root = false;
 575         new_mpath->sdata = sdata;
 576         new_mpath->flags = 0;
 577         skb_queue_head_init(&new_mpath->frame_queue);
 578         new_node->mpath = new_mpath;
 579         new_mpath->timer.data = (unsigned long) new_mpath;
 580         new_mpath->timer.function = mesh_path_timer;
 581         new_mpath->exp_time = jiffies;
 582         spin_lock_init(&new_mpath->state_lock);
 583         init_timer(&new_mpath->timer);
 584
 585         hlist_add_head_rcu(&new_node->list, bucket);
 586         if (atomic_inc_return(&tbl->entries) >=
 587             MEAN_CHAIN_LEN * (tbl->hash_mask + 1))
 588                 grow = 1;
 589
 590         mesh_paths_generation++;
 591
 592         if (grow) {
 593                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 594                 ieee80211_queue_work(&local->hw, &sdata->work);
 595         }
 596         mpath = new_mpath;
 597 found:
 598         spin_unlock(&tbl->hashwlock[hash_idx]);
 599         read_unlock_bh(&pathtbl_resize_lock);
 600         return mpath;
 601
 602 err_node_alloc:
 603         kfree(new_mpath);
 604 err_path_alloc:
 605         atomic_dec(&sdata->u.mesh.mpaths);
 606         spin_unlock(&tbl->hashwlock[hash_idx]);
 607         read_unlock_bh(&pathtbl_resize_lock);
 608         return ERR_PTR(err);
 609 }
 610
 611 static void mesh_table_free_rcu(struct rcu_head *rcu)
 612 {
 613         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 614
 615         mesh_table_free(tbl, false);
 616 }
 617
 618 void mesh_mpath_table_grow(void)
 619 {
 620         struct mesh_table *oldtbl, *newtbl;
 621
 622         write_lock_bh(&pathtbl_resize_lock);
 623         oldtbl = resize_dereference_mesh_paths();
 624         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 625         if (!newtbl)
 626                 goto out;
 627         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 628                 __mesh_table_free(newtbl);
 629                 goto out;
 630         }
 631         rcu_assign_pointer(mesh_paths, newtbl);
 632
 633         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 634
 635  out:
 636         write_unlock_bh(&pathtbl_resize_lock);
 637 }
 638
 639 void mesh_mpp_table_grow(void)
 640 {
 641         struct mesh_table *oldtbl, *newtbl;
 642
 643         write_lock_bh(&pathtbl_resize_lock);
 644         oldtbl = resize_dereference_mpp_paths();
 645         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 646         if (!newtbl)
 647                 goto out;
 648         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 649                 __mesh_table_free(newtbl);
 650                 goto out;
 651         }
 652         rcu_assign_pointer(mpp_paths, newtbl);
 653         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 654
 655  out:
 656         write_unlock_bh(&pathtbl_resize_lock);
 657 }
 658
 659 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 660                  const u8 *dst, const u8 *mpp)
 661 {
 662         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 663         struct ieee80211_local *local = sdata->local;
 664         struct mesh_table *tbl;
 665         struct mesh_path *mpath, *new_mpath;
 666         struct mpath_node *node, *new_node;
 667         struct hlist_head *bucket;
 668         int grow = 0;
 669         int err = 0;
 670         u32 hash_idx;
 671
 672         if (ether_addr_equal(dst, sdata->vif.addr))
 673                 /* never add ourselves as neighbours */
 674                 return -ENOTSUPP;
 675
 676         if (is_multicast_ether_addr(dst))
 677                 return -ENOTSUPP;
 678
 679         err = -ENOMEM;
 680         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 681         if (!new_mpath)
 682                 goto err_path_alloc;
 683
 684         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 685         if (!new_node)
 686                 goto err_node_alloc;
 687
 688         read_lock_bh(&pathtbl_resize_lock);
 689         memcpy(new_mpath->dst, dst, ETH_ALEN);
 690         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 691         new_mpath->sdata = sdata;
 692         new_mpath->flags = 0;
 693         skb_queue_head_init(&new_mpath->frame_queue);
 694         new_node->mpath = new_mpath;
 695         init_timer(&new_mpath->timer);
 696         new_mpath->exp_time = jiffies;
 697         spin_lock_init(&new_mpath->state_lock);
 698
 699         tbl = resize_dereference_mpp_paths();
 700
 701         hash_idx = mesh_table_hash(dst, sdata, tbl);
 702         bucket = &tbl->hash_buckets[hash_idx];
 703
 704         spin_lock(&tbl->hashwlock[hash_idx]);
 705
 706         err = -EEXIST;
 707         hlist_for_each_entry(node, bucket, list) {
 708                 mpath = node->mpath;
 709                 if (mpath->sdata == sdata &&
 710                     ether_addr_equal(dst, mpath->dst))
 711                         goto err_exists;
 712         }
 713
 714         hlist_add_head_rcu(&new_node->list, bucket);
 715         if (atomic_inc_return(&tbl->entries) >=
 716             MEAN_CHAIN_LEN * (tbl->hash_mask + 1))
 717                 grow = 1;
 718
 719         spin_unlock(&tbl->hashwlock[hash_idx]);
 720         read_unlock_bh(&pathtbl_resize_lock);
 721
 722         mpp_paths_generation++;
 723
 724         if (grow) {
 725                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 726                 ieee80211_queue_work(&local->hw, &sdata->work);
 727         }
 728         return 0;
 729
 730 err_exists:
 731         spin_unlock(&tbl->hashwlock[hash_idx]);
 732         read_unlock_bh(&pathtbl_resize_lock);
 733         kfree(new_node);
 734 err_node_alloc:
 735         kfree(new_mpath);
 736 err_path_alloc:
 737         return err;
 738 }
 739
 740
 741 /**
 742  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 743  *
 744  * @sta: broken peer link
 745  *
 746  * This function must be called from the rate control algorithm if enough
 747  * delivery errors suggest that a peer link is no longer usable.
 748  */
 749 void mesh_plink_broken(struct sta_info *sta)
 750 {
 751         struct mesh_table *tbl;
 752         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 753         struct mesh_path *mpath;
 754         struct mpath_node *node;
 755         struct ieee80211_sub_if_data *sdata = sta->sdata;
 756         int i;
 757
 758         rcu_read_lock();
 759         tbl = rcu_dereference(mesh_paths);
 760         for_each_mesh_entry(tbl, node, i) {
 761                 mpath = node->mpath;
 762                 if (rcu_access_pointer(mpath->next_hop) == sta &&
 763                     mpath->flags & MESH_PATH_ACTIVE &&
 764                     !(mpath->flags & MESH_PATH_FIXED)) {
 765                         spin_lock_bh(&mpath->state_lock);
 766                         mpath->flags &= ~MESH_PATH_ACTIVE;
 767                         ++mpath->sn;
 768                         spin_unlock_bh(&mpath->state_lock);
 769                         mesh_path_error_tx(sdata,
 770                                 sdata->u.mesh.mshcfg.element_ttl,
 771                                 mpath->dst, mpath->sn,
 772                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 773                 }
 774         }
 775         rcu_read_unlock();
 776 }
 777
 778 static void mesh_path_node_reclaim(struct rcu_head *rp)
 779 {
 780         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 781
 782         del_timer_sync(&node->mpath->timer);
 783         kfree(node->mpath);
 784         kfree(node);
 785 }
 786
 787 /* needs to be called with the corresponding hashwlock taken */
 788 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 789 {
 790         struct mesh_path *mpath = node->mpath;
 791         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 792
 793         spin_lock(&mpath->state_lock);
 794         mpath->flags |= MESH_PATH_RESOLVING;
 795         if (mpath->is_gate)
 796                 mesh_gate_del(tbl, mpath);
 797         hlist_del_rcu(&node->list);
 798         call_rcu(&node->rcu, mesh_path_node_reclaim);
 799         spin_unlock(&mpath->state_lock);
 800         atomic_dec(&sdata->u.mesh.mpaths);
 801         atomic_dec(&tbl->entries);
 802 }
 803
 804 /**
 805  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 806  *
 807  * @sta: mesh peer to match
 808  *
 809  * RCU notes: this function is called when a mesh plink transitions from
 810  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 811  * allows path creation. This will happen before the sta can be freed (because
 812  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 813  * protected against the plink disappearing.
 814  */
 815 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 816 {
 817         struct mesh_table *tbl;
 818         struct mesh_path *mpath;
 819         struct mpath_node *node;
 820         int i;
 821
 822         rcu_read_lock();
 823         read_lock_bh(&pathtbl_resize_lock);
 824         tbl = resize_dereference_mesh_paths();
 825         for_each_mesh_entry(tbl, node, i) {
 826                 mpath = node->mpath;
 827                 if (rcu_access_pointer(mpath->next_hop) == sta) {
 828                         spin_lock(&tbl->hashwlock[i]);
 829                         __mesh_path_del(tbl, node);
 830                         spin_unlock(&tbl->hashwlock[i]);
 831                 }
 832         }
 833         read_unlock_bh(&pathtbl_resize_lock);
 834         rcu_read_unlock();
 835 }
 836
 837 static void table_flush_by_iface(struct mesh_table *tbl,
 838                                  struct ieee80211_sub_if_data *sdata)
 839 {
 840         struct mesh_path *mpath;
 841         struct mpath_node *node;
 842         int i;
 843
 844         WARN_ON(!rcu_read_lock_held());
 845         for_each_mesh_entry(tbl, node, i) {
 846                 mpath = node->mpath;
 847                 if (mpath->sdata != sdata)
 848                         continue;
 849                 spin_lock_bh(&tbl->hashwlock[i]);
 850                 __mesh_path_del(tbl, node);
 851                 spin_unlock_bh(&tbl->hashwlock[i]);
 852         }
 853 }
 854
 855 /**
 856  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 857  *
 858  * This function deletes both mesh paths as well as mesh portal paths.
 859  *
 860  * @sdata: interface data to match
 861  *
 862  */
 863 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 864 {
 865         struct mesh_table *tbl;
 866
 867         rcu_read_lock();
 868         read_lock_bh(&pathtbl_resize_lock);
 869         tbl = resize_dereference_mesh_paths();
 870         table_flush_by_iface(tbl, sdata);
 871         tbl = resize_dereference_mpp_paths();
 872         table_flush_by_iface(tbl, sdata);
 873         read_unlock_bh(&pathtbl_resize_lock);
 874         rcu_read_unlock();
 875 }
 876
 877 /**
 878  * mesh_path_del - delete a mesh path from the table
 879  *
 880  * @addr: dst address (ETH_ALEN length)
 881  * @sdata: local subif
 882  *
 883  * Returns: 0 if successful
 884  */
 885 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 886 {
 887         struct mesh_table *tbl;
 888         struct mesh_path *mpath;
 889         struct mpath_node *node;
 890         struct hlist_head *bucket;
 891         int hash_idx;
 892         int err = 0;
 893
 894         read_lock_bh(&pathtbl_resize_lock);
 895         tbl = resize_dereference_mesh_paths();
 896         hash_idx = mesh_table_hash(addr, sdata, tbl);
 897         bucket = &tbl->hash_buckets[hash_idx];
 898
 899         spin_lock(&tbl->hashwlock[hash_idx]);
 900         hlist_for_each_entry(node, bucket, list) {
 901                 mpath = node->mpath;
 902                 if (mpath->sdata == sdata &&
 903                     ether_addr_equal(addr, mpath->dst)) {
 904                         __mesh_path_del(tbl, node);
 905                         goto enddel;
 906                 }
 907         }
 908
 909         err = -ENXIO;
 910 enddel:
 911         mesh_paths_generation++;
 912         spin_unlock(&tbl->hashwlock[hash_idx]);
 913         read_unlock_bh(&pathtbl_resize_lock);
 914         return err;
 915 }
 916
 917 /**
 918  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 919  *
 920  * @mpath: mesh path to activate
 921  *
 922  * Locking: the state_lock of the mpath structure must NOT be held when calling
 923  * this function.
 924  */
 925 void mesh_path_tx_pending(struct mesh_path *mpath)
 926 {
 927         if (mpath->flags & MESH_PATH_ACTIVE)
 928                 ieee80211_add_pending_skbs(mpath->sdata->local,
 929                                 &mpath->frame_queue);
 930 }
 931
 932 /**
 933  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 934  *
 935  * @mpath: mesh path whose queue will be emptied
 936  *
 937  * If there is only one gate, the frames are transferred from the failed mpath
 938  * queue to that gate's queue.  If there are more than one gates, the frames
 939  * are copied from each gate to the next.  After frames are copied, the
 940  * mpath queues are emptied onto the transmission queue.
 941  */
 942 int mesh_path_send_to_gates(struct mesh_path *mpath)
 943 {
 944         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 945         struct mesh_table *tbl;
 946         struct mesh_path *from_mpath = mpath;
 947         struct mpath_node *gate = NULL;
 948         bool copy = false;
 949         struct hlist_head *known_gates;
 950
 951         rcu_read_lock();
 952         tbl = rcu_dereference(mesh_paths);
 953         known_gates = tbl->known_gates;
 954         rcu_read_unlock();
 955
 956         if (!known_gates)
 957                 return -EHOSTUNREACH;
 958
 959         hlist_for_each_entry_rcu(gate, known_gates, list) {
 960                 if (gate->mpath->sdata != sdata)
 961                         continue;
 962
 963                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 964                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 965                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 966                         from_mpath = gate->mpath;
 967                         copy = true;
 968                 } else {
 969                         mpath_dbg(sdata,
 970                                   "Not forwarding to %pM (flags %#x)\n",
 971                                   gate->mpath->dst, gate->mpath->flags);
 972                 }
 973         }
 974
 975         hlist_for_each_entry_rcu(gate, known_gates, list)
 976                 if (gate->mpath->sdata == sdata) {
 977                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 978                         mesh_path_tx_pending(gate->mpath);
 979                 }
 980
 981         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 982 }
 983
 984 /**
 985  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 986  *
 987  * @skb: frame to discard
 988  * @sdata: network subif the frame was to be sent through
 989  *
 990  * Locking: the function must me called within a rcu_read_lock region
 991  */
 992 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 993                              struct sk_buff *skb)
 994 {
 995         kfree_skb(skb);
 996         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 997 }
 998
 999 /**
1000  * mesh_path_flush_pending - free the pending queue of a mesh path
1001  *
1002  * @mpath: mesh path whose queue has to be freed
1003  *
1004  * Locking: the function must me called within a rcu_read_lock region
1005  */
1006 void mesh_path_flush_pending(struct mesh_path *mpath)
1007 {
1008         struct sk_buff *skb;
1009
1010         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
1011                 mesh_path_discard_frame(mpath->sdata, skb);
1012 }
1013
1014 /**
1015  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1016  *
1017  * @mpath: the mesh path to modify
1018  * @next_hop: the next hop to force
1019  *
1020  * Locking: this function must be called holding mpath->state_lock
1021  */
1022 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1023 {
1024         spin_lock_bh(&mpath->state_lock);
1025         mesh_path_assign_nexthop(mpath, next_hop);
1026         mpath->sn = 0xffff;
1027         mpath->metric = 0;
1028         mpath->hop_count = 0;
1029         mpath->exp_time = 0;
1030         mpath->flags |= MESH_PATH_FIXED;
1031         mesh_path_activate(mpath);
1032         spin_unlock_bh(&mpath->state_lock);
1033         mesh_path_tx_pending(mpath);
1034 }
1035
1036 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1037 {
1038         struct mesh_path *mpath;
1039         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1040         mpath = node->mpath;
1041         hlist_del_rcu(p);
1042         if (free_leafs) {
1043                 del_timer_sync(&mpath->timer);
1044                 kfree(mpath);
1045         }
1046         kfree(node);
1047 }
1048
1049 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1050 {
1051         struct mesh_path *mpath;
1052         struct mpath_node *node, *new_node;
1053         u32 hash_idx;
1054
1055         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1056         if (new_node == NULL)
1057                 return -ENOMEM;
1058
1059         node = hlist_entry(p, struct mpath_node, list);
1060         mpath = node->mpath;
1061         new_node->mpath = mpath;
1062         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1063         hlist_add_head(&new_node->list,
1064                         &newtbl->hash_buckets[hash_idx]);
1065         return 0;
1066 }
1067
1068 int mesh_pathtbl_init(void)
1069 {
1070         struct mesh_table *tbl_path, *tbl_mpp;
1071         int ret;
1072
1073         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1074         if (!tbl_path)
1075                 return -ENOMEM;
1076         tbl_path->free_node = &mesh_path_node_free;
1077         tbl_path->copy_node = &mesh_path_node_copy;
1078         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1079         if (!tbl_path->known_gates) {
1080                 ret = -ENOMEM;
1081                 goto free_path;
1082         }
1083         INIT_HLIST_HEAD(tbl_path->known_gates);
1084
1085
1086         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1087         if (!tbl_mpp) {
1088                 ret = -ENOMEM;
1089                 goto free_path;
1090         }
1091         tbl_mpp->free_node = &mesh_path_node_free;
1092         tbl_mpp->copy_node = &mesh_path_node_copy;
1093         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1094         if (!tbl_mpp->known_gates) {
1095                 ret = -ENOMEM;
1096                 goto free_mpp;
1097         }
1098         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1099
1100         /* Need no locking since this is during init */
1101         RCU_INIT_POINTER(mesh_paths, tbl_path);
1102         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1103
1104         return 0;
1105
1106 free_mpp:
1107         mesh_table_free(tbl_mpp, true);
1108 free_path:
1109         mesh_table_free(tbl_path, true);
1110         return ret;
1111 }
1112
1113 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1114 {
1115         struct mesh_table *tbl;
1116         struct mesh_path *mpath;
1117         struct mpath_node *node;
1118         int i;
1119
1120         rcu_read_lock();
1121         tbl = rcu_dereference(mesh_paths);
1122         for_each_mesh_entry(tbl, node, i) {
1123                 if (node->mpath->sdata != sdata)
1124                         continue;
1125                 mpath = node->mpath;
1126                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1127                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1128                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1129                         mesh_path_del(mpath->sdata, mpath->dst);
1130         }
1131         rcu_read_unlock();
1132 }
1133
1134 void mesh_pathtbl_unregister(void)
1135 {
1136         /* no need for locking during exit path */
1137         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1138         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1139 }