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         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  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 414  * @mpath: gate path to add to table
 415  */
 416 int mesh_path_add_gate(struct mesh_path *mpath)
 417 {
 418         struct mesh_table *tbl;
 419         struct mpath_node *gate, *new_gate;
 420         int err;
 421
 422         rcu_read_lock();
 423         tbl = rcu_dereference(mesh_paths);
 424
 425         hlist_for_each_entry_rcu(gate, tbl->known_gates, list)
 426                 if (gate->mpath == mpath) {
 427                         err = -EEXIST;
 428                         goto err_rcu;
 429                 }
 430
 431         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 432         if (!new_gate) {
 433                 err = -ENOMEM;
 434                 goto err_rcu;
 435         }
 436
 437         mpath->is_gate = true;
 438         mpath->sdata->u.mesh.num_gates++;
 439         new_gate->mpath = mpath;
 440         spin_lock_bh(&tbl->gates_lock);
 441         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 442         spin_unlock_bh(&tbl->gates_lock);
 443         mpath_dbg(mpath->sdata,
 444                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 445                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 446         err = 0;
 447 err_rcu:
 448         rcu_read_unlock();
 449         return err;
 450 }
 451
 452 /**
 453  * mesh_gate_del - remove a mesh gate from the list of known gates
 454  * @tbl: table which holds our list of known gates
 455  * @mpath: gate mpath
 456  *
 457  * Locking: must be called inside rcu_read_lock() section
 458  */
 459 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 460 {
 461         struct mpath_node *gate;
 462         struct hlist_node *q;
 463
 464         hlist_for_each_entry_safe(gate, q, tbl->known_gates, list) {
 465                 if (gate->mpath != mpath)
 466                         continue;
 467                 spin_lock_bh(&tbl->gates_lock);
 468                 hlist_del_rcu(&gate->list);
 469                 kfree_rcu(gate, rcu);
 470                 spin_unlock_bh(&tbl->gates_lock);
 471                 mpath->sdata->u.mesh.num_gates--;
 472                 mpath->is_gate = false;
 473                 mpath_dbg(mpath->sdata,
 474                           "Mesh path: Deleted gate: %pM. %d known gates\n",
 475                           mpath->dst, mpath->sdata->u.mesh.num_gates);
 476                 break;
 477         }
 478 }
 479
 480 /**
 481  * mesh_gate_num - number of gates known to this interface
 482  * @sdata: subif data
 483  */
 484 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 485 {
 486         return sdata->u.mesh.num_gates;
 487 }
 488
 489 /**
 490  * mesh_path_add - allocate and add a new path to the mesh path table
 491  * @dst: destination address of the path (ETH_ALEN length)
 492  * @sdata: local subif
 493  *
 494  * Returns: 0 on success
 495  *
 496  * State: the initial state of the new path is set to 0
 497  */
 498 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 499                                 const u8 *dst)
 500 {
 501         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 502         struct ieee80211_local *local = sdata->local;
 503         struct mesh_table *tbl;
 504         struct mesh_path *mpath, *new_mpath;
 505         struct mpath_node *node, *new_node;
 506         struct hlist_head *bucket;
 507         int grow = 0;
 508         int err;
 509         u32 hash_idx;
 510
 511         if (ether_addr_equal(dst, sdata->vif.addr))
 512                 /* never add ourselves as neighbours */
 513                 return ERR_PTR(-ENOTSUPP);
 514
 515         if (is_multicast_ether_addr(dst))
 516                 return ERR_PTR(-ENOTSUPP);
 517
 518         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 519                 return ERR_PTR(-ENOSPC);
 520
 521         read_lock_bh(&pathtbl_resize_lock);
 522         tbl = resize_dereference_mesh_paths();
 523
 524         hash_idx = mesh_table_hash(dst, sdata, tbl);
 525         bucket = &tbl->hash_buckets[hash_idx];
 526
 527         spin_lock(&tbl->hashwlock[hash_idx]);
 528
 529         hlist_for_each_entry(node, bucket, list) {
 530                 mpath = node->mpath;
 531                 if (mpath->sdata == sdata &&
 532                     ether_addr_equal(dst, mpath->dst))
 533                         goto found;
 534         }
 535
 536         err = -ENOMEM;
 537         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 538         if (!new_mpath)
 539                 goto err_path_alloc;
 540
 541         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 542         if (!new_node)
 543                 goto err_node_alloc;
 544
 545         memcpy(new_mpath->dst, dst, ETH_ALEN);
 546         eth_broadcast_addr(new_mpath->rann_snd_addr);
 547         new_mpath->is_root = false;
 548         new_mpath->sdata = sdata;
 549         new_mpath->flags = 0;
 550         skb_queue_head_init(&new_mpath->frame_queue);
 551         new_node->mpath = new_mpath;
 552         new_mpath->timer.data = (unsigned long) new_mpath;
 553         new_mpath->timer.function = mesh_path_timer;
 554         new_mpath->exp_time = jiffies;
 555         spin_lock_init(&new_mpath->state_lock);
 556         init_timer(&new_mpath->timer);
 557
 558         hlist_add_head_rcu(&new_node->list, bucket);
 559         if (atomic_inc_return(&tbl->entries) >=
 560             tbl->mean_chain_len * (tbl->hash_mask + 1))
 561                 grow = 1;
 562
 563         mesh_paths_generation++;
 564
 565         if (grow) {
 566                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 567                 ieee80211_queue_work(&local->hw, &sdata->work);
 568         }
 569         mpath = new_mpath;
 570 found:
 571         spin_unlock(&tbl->hashwlock[hash_idx]);
 572         read_unlock_bh(&pathtbl_resize_lock);
 573         return mpath;
 574
 575 err_node_alloc:
 576         kfree(new_mpath);
 577 err_path_alloc:
 578         atomic_dec(&sdata->u.mesh.mpaths);
 579         spin_unlock(&tbl->hashwlock[hash_idx]);
 580         read_unlock_bh(&pathtbl_resize_lock);
 581         return ERR_PTR(err);
 582 }
 583
 584 static void mesh_table_free_rcu(struct rcu_head *rcu)
 585 {
 586         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 587
 588         mesh_table_free(tbl, false);
 589 }
 590
 591 void mesh_mpath_table_grow(void)
 592 {
 593         struct mesh_table *oldtbl, *newtbl;
 594
 595         write_lock_bh(&pathtbl_resize_lock);
 596         oldtbl = resize_dereference_mesh_paths();
 597         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 598         if (!newtbl)
 599                 goto out;
 600         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 601                 __mesh_table_free(newtbl);
 602                 goto out;
 603         }
 604         rcu_assign_pointer(mesh_paths, newtbl);
 605
 606         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 607
 608  out:
 609         write_unlock_bh(&pathtbl_resize_lock);
 610 }
 611
 612 void mesh_mpp_table_grow(void)
 613 {
 614         struct mesh_table *oldtbl, *newtbl;
 615
 616         write_lock_bh(&pathtbl_resize_lock);
 617         oldtbl = resize_dereference_mpp_paths();
 618         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 619         if (!newtbl)
 620                 goto out;
 621         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 622                 __mesh_table_free(newtbl);
 623                 goto out;
 624         }
 625         rcu_assign_pointer(mpp_paths, newtbl);
 626         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 627
 628  out:
 629         write_unlock_bh(&pathtbl_resize_lock);
 630 }
 631
 632 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 633                  const u8 *dst, const u8 *mpp)
 634 {
 635         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 636         struct ieee80211_local *local = sdata->local;
 637         struct mesh_table *tbl;
 638         struct mesh_path *mpath, *new_mpath;
 639         struct mpath_node *node, *new_node;
 640         struct hlist_head *bucket;
 641         int grow = 0;
 642         int err = 0;
 643         u32 hash_idx;
 644
 645         if (ether_addr_equal(dst, sdata->vif.addr))
 646                 /* never add ourselves as neighbours */
 647                 return -ENOTSUPP;
 648
 649         if (is_multicast_ether_addr(dst))
 650                 return -ENOTSUPP;
 651
 652         err = -ENOMEM;
 653         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 654         if (!new_mpath)
 655                 goto err_path_alloc;
 656
 657         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 658         if (!new_node)
 659                 goto err_node_alloc;
 660
 661         read_lock_bh(&pathtbl_resize_lock);
 662         memcpy(new_mpath->dst, dst, ETH_ALEN);
 663         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 664         new_mpath->sdata = sdata;
 665         new_mpath->flags = 0;
 666         skb_queue_head_init(&new_mpath->frame_queue);
 667         new_node->mpath = new_mpath;
 668         init_timer(&new_mpath->timer);
 669         new_mpath->exp_time = jiffies;
 670         spin_lock_init(&new_mpath->state_lock);
 671
 672         tbl = resize_dereference_mpp_paths();
 673
 674         hash_idx = mesh_table_hash(dst, sdata, tbl);
 675         bucket = &tbl->hash_buckets[hash_idx];
 676
 677         spin_lock(&tbl->hashwlock[hash_idx]);
 678
 679         err = -EEXIST;
 680         hlist_for_each_entry(node, bucket, list) {
 681                 mpath = node->mpath;
 682                 if (mpath->sdata == sdata &&
 683                     ether_addr_equal(dst, mpath->dst))
 684                         goto err_exists;
 685         }
 686
 687         hlist_add_head_rcu(&new_node->list, bucket);
 688         if (atomic_inc_return(&tbl->entries) >=
 689             tbl->mean_chain_len * (tbl->hash_mask + 1))
 690                 grow = 1;
 691
 692         spin_unlock(&tbl->hashwlock[hash_idx]);
 693         read_unlock_bh(&pathtbl_resize_lock);
 694         if (grow) {
 695                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 696                 ieee80211_queue_work(&local->hw, &sdata->work);
 697         }
 698         return 0;
 699
 700 err_exists:
 701         spin_unlock(&tbl->hashwlock[hash_idx]);
 702         read_unlock_bh(&pathtbl_resize_lock);
 703         kfree(new_node);
 704 err_node_alloc:
 705         kfree(new_mpath);
 706 err_path_alloc:
 707         return err;
 708 }
 709
 710
 711 /**
 712  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 713  *
 714  * @sta: broken peer link
 715  *
 716  * This function must be called from the rate control algorithm if enough
 717  * delivery errors suggest that a peer link is no longer usable.
 718  */
 719 void mesh_plink_broken(struct sta_info *sta)
 720 {
 721         struct mesh_table *tbl;
 722         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 723         struct mesh_path *mpath;
 724         struct mpath_node *node;
 725         struct ieee80211_sub_if_data *sdata = sta->sdata;
 726         int i;
 727
 728         rcu_read_lock();
 729         tbl = rcu_dereference(mesh_paths);
 730         for_each_mesh_entry(tbl, node, i) {
 731                 mpath = node->mpath;
 732                 if (rcu_dereference(mpath->next_hop) == sta &&
 733                     mpath->flags & MESH_PATH_ACTIVE &&
 734                     !(mpath->flags & MESH_PATH_FIXED)) {
 735                         spin_lock_bh(&mpath->state_lock);
 736                         mpath->flags &= ~MESH_PATH_ACTIVE;
 737                         ++mpath->sn;
 738                         spin_unlock_bh(&mpath->state_lock);
 739                         mesh_path_error_tx(sdata,
 740                                 sdata->u.mesh.mshcfg.element_ttl,
 741                                 mpath->dst, mpath->sn,
 742                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 743                 }
 744         }
 745         rcu_read_unlock();
 746 }
 747
 748 static void mesh_path_node_reclaim(struct rcu_head *rp)
 749 {
 750         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 751         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 752
 753         del_timer_sync(&node->mpath->timer);
 754         atomic_dec(&sdata->u.mesh.mpaths);
 755         kfree(node->mpath);
 756         kfree(node);
 757 }
 758
 759 /* needs to be called with the corresponding hashwlock taken */
 760 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 761 {
 762         struct mesh_path *mpath;
 763         mpath = node->mpath;
 764         spin_lock(&mpath->state_lock);
 765         mpath->flags |= MESH_PATH_RESOLVING;
 766         if (mpath->is_gate)
 767                 mesh_gate_del(tbl, mpath);
 768         hlist_del_rcu(&node->list);
 769         call_rcu(&node->rcu, mesh_path_node_reclaim);
 770         spin_unlock(&mpath->state_lock);
 771         atomic_dec(&tbl->entries);
 772 }
 773
 774 /**
 775  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 776  *
 777  * @sta: mesh peer to match
 778  *
 779  * RCU notes: this function is called when a mesh plink transitions from
 780  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 781  * allows path creation. This will happen before the sta can be freed (because
 782  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 783  * protected against the plink disappearing.
 784  */
 785 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 786 {
 787         struct mesh_table *tbl;
 788         struct mesh_path *mpath;
 789         struct mpath_node *node;
 790         int i;
 791
 792         rcu_read_lock();
 793         read_lock_bh(&pathtbl_resize_lock);
 794         tbl = resize_dereference_mesh_paths();
 795         for_each_mesh_entry(tbl, node, i) {
 796                 mpath = node->mpath;
 797                 if (rcu_dereference(mpath->next_hop) == sta) {
 798                         spin_lock(&tbl->hashwlock[i]);
 799                         __mesh_path_del(tbl, node);
 800                         spin_unlock(&tbl->hashwlock[i]);
 801                 }
 802         }
 803         read_unlock_bh(&pathtbl_resize_lock);
 804         rcu_read_unlock();
 805 }
 806
 807 static void table_flush_by_iface(struct mesh_table *tbl,
 808                                  struct ieee80211_sub_if_data *sdata)
 809 {
 810         struct mesh_path *mpath;
 811         struct mpath_node *node;
 812         int i;
 813
 814         WARN_ON(!rcu_read_lock_held());
 815         for_each_mesh_entry(tbl, node, i) {
 816                 mpath = node->mpath;
 817                 if (mpath->sdata != sdata)
 818                         continue;
 819                 spin_lock_bh(&tbl->hashwlock[i]);
 820                 __mesh_path_del(tbl, node);
 821                 spin_unlock_bh(&tbl->hashwlock[i]);
 822         }
 823 }
 824
 825 /**
 826  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 827  *
 828  * This function deletes both mesh paths as well as mesh portal paths.
 829  *
 830  * @sdata: interface data to match
 831  *
 832  */
 833 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 834 {
 835         struct mesh_table *tbl;
 836
 837         rcu_read_lock();
 838         read_lock_bh(&pathtbl_resize_lock);
 839         tbl = resize_dereference_mesh_paths();
 840         table_flush_by_iface(tbl, sdata);
 841         tbl = resize_dereference_mpp_paths();
 842         table_flush_by_iface(tbl, sdata);
 843         read_unlock_bh(&pathtbl_resize_lock);
 844         rcu_read_unlock();
 845 }
 846
 847 /**
 848  * mesh_path_del - delete a mesh path from the table
 849  *
 850  * @addr: dst address (ETH_ALEN length)
 851  * @sdata: local subif
 852  *
 853  * Returns: 0 if successful
 854  */
 855 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 856 {
 857         struct mesh_table *tbl;
 858         struct mesh_path *mpath;
 859         struct mpath_node *node;
 860         struct hlist_head *bucket;
 861         int hash_idx;
 862         int err = 0;
 863
 864         read_lock_bh(&pathtbl_resize_lock);
 865         tbl = resize_dereference_mesh_paths();
 866         hash_idx = mesh_table_hash(addr, sdata, tbl);
 867         bucket = &tbl->hash_buckets[hash_idx];
 868
 869         spin_lock(&tbl->hashwlock[hash_idx]);
 870         hlist_for_each_entry(node, bucket, list) {
 871                 mpath = node->mpath;
 872                 if (mpath->sdata == sdata &&
 873                     ether_addr_equal(addr, mpath->dst)) {
 874                         __mesh_path_del(tbl, node);
 875                         goto enddel;
 876                 }
 877         }
 878
 879         err = -ENXIO;
 880 enddel:
 881         mesh_paths_generation++;
 882         spin_unlock(&tbl->hashwlock[hash_idx]);
 883         read_unlock_bh(&pathtbl_resize_lock);
 884         return err;
 885 }
 886
 887 /**
 888  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 889  *
 890  * @mpath: mesh path to activate
 891  *
 892  * Locking: the state_lock of the mpath structure must NOT be held when calling
 893  * this function.
 894  */
 895 void mesh_path_tx_pending(struct mesh_path *mpath)
 896 {
 897         if (mpath->flags & MESH_PATH_ACTIVE)
 898                 ieee80211_add_pending_skbs(mpath->sdata->local,
 899                                 &mpath->frame_queue);
 900 }
 901
 902 /**
 903  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 904  *
 905  * @mpath: mesh path whose queue will be emptied
 906  *
 907  * If there is only one gate, the frames are transferred from the failed mpath
 908  * queue to that gate's queue.  If there are more than one gates, the frames
 909  * are copied from each gate to the next.  After frames are copied, the
 910  * mpath queues are emptied onto the transmission queue.
 911  */
 912 int mesh_path_send_to_gates(struct mesh_path *mpath)
 913 {
 914         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 915         struct mesh_table *tbl;
 916         struct mesh_path *from_mpath = mpath;
 917         struct mpath_node *gate = NULL;
 918         bool copy = false;
 919         struct hlist_head *known_gates;
 920
 921         rcu_read_lock();
 922         tbl = rcu_dereference(mesh_paths);
 923         known_gates = tbl->known_gates;
 924         rcu_read_unlock();
 925
 926         if (!known_gates)
 927                 return -EHOSTUNREACH;
 928
 929         hlist_for_each_entry_rcu(gate, known_gates, list) {
 930                 if (gate->mpath->sdata != sdata)
 931                         continue;
 932
 933                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 934                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 935                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 936                         from_mpath = gate->mpath;
 937                         copy = true;
 938                 } else {
 939                         mpath_dbg(sdata,
 940                                   "Not forwarding %p (flags %#x)\n",
 941                                   gate->mpath, gate->mpath->flags);
 942                 }
 943         }
 944
 945         hlist_for_each_entry_rcu(gate, known_gates, list)
 946                 if (gate->mpath->sdata == sdata) {
 947                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 948                         mesh_path_tx_pending(gate->mpath);
 949                 }
 950
 951         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 952 }
 953
 954 /**
 955  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 956  *
 957  * @skb: frame to discard
 958  * @sdata: network subif the frame was to be sent through
 959  *
 960  * Locking: the function must me called within a rcu_read_lock region
 961  */
 962 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 963                              struct sk_buff *skb)
 964 {
 965         kfree_skb(skb);
 966         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 967 }
 968
 969 /**
 970  * mesh_path_flush_pending - free the pending queue of a mesh path
 971  *
 972  * @mpath: mesh path whose queue has to be freed
 973  *
 974  * Locking: the function must me called within a rcu_read_lock region
 975  */
 976 void mesh_path_flush_pending(struct mesh_path *mpath)
 977 {
 978         struct sk_buff *skb;
 979
 980         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 981                 mesh_path_discard_frame(mpath->sdata, skb);
 982 }
 983
 984 /**
 985  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 986  *
 987  * @mpath: the mesh path to modify
 988  * @next_hop: the next hop to force
 989  *
 990  * Locking: this function must be called holding mpath->state_lock
 991  */
 992 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 993 {
 994         spin_lock_bh(&mpath->state_lock);
 995         mesh_path_assign_nexthop(mpath, next_hop);
 996         mpath->sn = 0xffff;
 997         mpath->metric = 0;
 998         mpath->hop_count = 0;
 999         mpath->exp_time = 0;
1000         mpath->flags |= MESH_PATH_FIXED;
1001         mesh_path_activate(mpath);
1002         spin_unlock_bh(&mpath->state_lock);
1003         mesh_path_tx_pending(mpath);
1004 }
1005
1006 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1007 {
1008         struct mesh_path *mpath;
1009         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1010         mpath = node->mpath;
1011         hlist_del_rcu(p);
1012         if (free_leafs) {
1013                 del_timer_sync(&mpath->timer);
1014                 kfree(mpath);
1015         }
1016         kfree(node);
1017 }
1018
1019 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1020 {
1021         struct mesh_path *mpath;
1022         struct mpath_node *node, *new_node;
1023         u32 hash_idx;
1024
1025         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1026         if (new_node == NULL)
1027                 return -ENOMEM;
1028
1029         node = hlist_entry(p, struct mpath_node, list);
1030         mpath = node->mpath;
1031         new_node->mpath = mpath;
1032         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1033         hlist_add_head(&new_node->list,
1034                         &newtbl->hash_buckets[hash_idx]);
1035         return 0;
1036 }
1037
1038 int mesh_pathtbl_init(void)
1039 {
1040         struct mesh_table *tbl_path, *tbl_mpp;
1041         int ret;
1042
1043         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1044         if (!tbl_path)
1045                 return -ENOMEM;
1046         tbl_path->free_node = &mesh_path_node_free;
1047         tbl_path->copy_node = &mesh_path_node_copy;
1048         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1049         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1050         if (!tbl_path->known_gates) {
1051                 ret = -ENOMEM;
1052                 goto free_path;
1053         }
1054         INIT_HLIST_HEAD(tbl_path->known_gates);
1055
1056
1057         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1058         if (!tbl_mpp) {
1059                 ret = -ENOMEM;
1060                 goto free_path;
1061         }
1062         tbl_mpp->free_node = &mesh_path_node_free;
1063         tbl_mpp->copy_node = &mesh_path_node_copy;
1064         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1065         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1066         if (!tbl_mpp->known_gates) {
1067                 ret = -ENOMEM;
1068                 goto free_mpp;
1069         }
1070         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1071
1072         /* Need no locking since this is during init */
1073         RCU_INIT_POINTER(mesh_paths, tbl_path);
1074         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1075
1076         return 0;
1077
1078 free_mpp:
1079         mesh_table_free(tbl_mpp, true);
1080 free_path:
1081         mesh_table_free(tbl_path, true);
1082         return ret;
1083 }
1084
1085 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1086 {
1087         struct mesh_table *tbl;
1088         struct mesh_path *mpath;
1089         struct mpath_node *node;
1090         int i;
1091
1092         rcu_read_lock();
1093         tbl = rcu_dereference(mesh_paths);
1094         for_each_mesh_entry(tbl, node, i) {
1095                 if (node->mpath->sdata != sdata)
1096                         continue;
1097                 mpath = node->mpath;
1098                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1099                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1100                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1101                         mesh_path_del(mpath->sdata, mpath->dst);
1102         }
1103         rcu_read_unlock();
1104 }
1105
1106 void mesh_pathtbl_unregister(void)
1107 {
1108         /* no need for locking during exit path */
1109         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1110         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1111 }