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 "ieee80211_i.h"
  18 #include "mesh.h"
  19
  20 #ifdef CONFIG_MAC80211_VERBOSE_MPATH_DEBUG
  21 #define mpath_dbg(fmt, args...) printk(KERN_DEBUG fmt, ##args)
  22 #else
  23 #define mpath_dbg(fmt, args...) do { (void)(0); } while (0)
  24 #endif
  25
  26 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  27 #define INIT_PATHS_SIZE_ORDER   2
  28
  29 /* Keep the mean chain length below this constant */
  30 #define MEAN_CHAIN_LEN          2
  31
  32 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  33                                 time_after(jiffies, mpath->exp_time) && \
  34                                 !(mpath->flags & MESH_PATH_FIXED))
  35
  36 struct mpath_node {
  37         struct hlist_node list;
  38         struct rcu_head rcu;
  39         /* This indirection allows two different tables to point to the same
  40          * mesh_path structure, useful when resizing
  41          */
  42         struct mesh_path *mpath;
  43 };
  44
  45 static struct mesh_table __rcu *mesh_paths;
  46 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  47
  48 int mesh_paths_generation;
  49
  50 /* This lock will have the grow table function as writer and add / delete nodes
  51  * as readers. When reading the table (i.e. doing lookups) we are well protected
  52  * by RCU
  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, p, node, i) \
  76         for (i = 0; i <= tbl->hash_mask; i++) \
  77                 hlist_for_each_entry_rcu(node, p, &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
 113         return newtbl;
 114 }
 115
 116 static void __mesh_table_free(struct mesh_table *tbl)
 117 {
 118         kfree(tbl->hash_buckets);
 119         kfree(tbl->hashwlock);
 120         kfree(tbl);
 121 }
 122
 123 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 124 {
 125         struct hlist_head *mesh_hash;
 126         struct hlist_node *p, *q;
 127         int i;
 128
 129         mesh_hash = tbl->hash_buckets;
 130         for (i = 0; i <= tbl->hash_mask; i++) {
 131                 spin_lock_bh(&tbl->hashwlock[i]);
 132                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 133                         tbl->free_node(p, free_leafs);
 134                         atomic_dec(&tbl->entries);
 135                 }
 136                 spin_unlock_bh(&tbl->hashwlock[i]);
 137         }
 138         __mesh_table_free(tbl);
 139 }
 140
 141 static int mesh_table_grow(struct mesh_table *oldtbl,
 142                            struct mesh_table *newtbl)
 143 {
 144         struct hlist_head *oldhash;
 145         struct hlist_node *p, *q;
 146         int i;
 147
 148         if (atomic_read(&oldtbl->entries)
 149                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 150                 return -EAGAIN;
 151
 152         newtbl->free_node = oldtbl->free_node;
 153         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 154         newtbl->copy_node = oldtbl->copy_node;
 155         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 156
 157         oldhash = oldtbl->hash_buckets;
 158         for (i = 0; i <= oldtbl->hash_mask; i++)
 159                 hlist_for_each(p, &oldhash[i])
 160                         if (oldtbl->copy_node(p, newtbl) < 0)
 161                                 goto errcopy;
 162
 163         return 0;
 164
 165 errcopy:
 166         for (i = 0; i <= newtbl->hash_mask; i++) {
 167                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 168                         oldtbl->free_node(p, 0);
 169         }
 170         return -ENOMEM;
 171 }
 172
 173 static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
 174                            struct mesh_table *tbl)
 175 {
 176         /* Use last four bytes of hw addr and interface index as hash index */
 177         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
 178                 & tbl->hash_mask;
 179 }
 180
 181
 182 /**
 183  *
 184  * mesh_path_assign_nexthop - update mesh path next hop
 185  *
 186  * @mpath: mesh path to update
 187  * @sta: next hop to assign
 188  *
 189  * Locking: mpath->state_lock must be held when calling this function
 190  */
 191 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 192 {
 193         struct sk_buff *skb;
 194         struct ieee80211_hdr *hdr;
 195         struct sk_buff_head tmpq;
 196         unsigned long flags;
 197
 198         rcu_assign_pointer(mpath->next_hop, sta);
 199
 200         __skb_queue_head_init(&tmpq);
 201
 202         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 203
 204         while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
 205                 hdr = (struct ieee80211_hdr *) skb->data;
 206                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 207                 __skb_queue_tail(&tmpq, skb);
 208         }
 209
 210         skb_queue_splice(&tmpq, &mpath->frame_queue);
 211         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 212 }
 213
 214
 215 /**
 216  * mesh_path_lookup - look up a path in the mesh path table
 217  * @dst: hardware address (ETH_ALEN length) of destination
 218  * @sdata: local subif
 219  *
 220  * Returns: pointer to the mesh path structure, or NULL if not found
 221  *
 222  * Locking: must be called within a read rcu section.
 223  */
 224 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 225 {
 226         struct mesh_path *mpath;
 227         struct hlist_node *n;
 228         struct hlist_head *bucket;
 229         struct mesh_table *tbl;
 230         struct mpath_node *node;
 231
 232         tbl = rcu_dereference(mesh_paths);
 233
 234         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 235         hlist_for_each_entry_rcu(node, n, bucket, list) {
 236                 mpath = node->mpath;
 237                 if (mpath->sdata == sdata &&
 238                                 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 239                         if (MPATH_EXPIRED(mpath)) {
 240                                 spin_lock_bh(&mpath->state_lock);
 241                                 if (MPATH_EXPIRED(mpath))
 242                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 243                                 spin_unlock_bh(&mpath->state_lock);
 244                         }
 245                         return mpath;
 246                 }
 247         }
 248         return NULL;
 249 }
 250
 251 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 252 {
 253         struct mesh_path *mpath;
 254         struct hlist_node *n;
 255         struct hlist_head *bucket;
 256         struct mesh_table *tbl;
 257         struct mpath_node *node;
 258
 259         tbl = rcu_dereference(mpp_paths);
 260
 261         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 262         hlist_for_each_entry_rcu(node, n, bucket, list) {
 263                 mpath = node->mpath;
 264                 if (mpath->sdata == sdata &&
 265                     memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 266                         if (MPATH_EXPIRED(mpath)) {
 267                                 spin_lock_bh(&mpath->state_lock);
 268                                 if (MPATH_EXPIRED(mpath))
 269                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 270                                 spin_unlock_bh(&mpath->state_lock);
 271                         }
 272                         return mpath;
 273                 }
 274         }
 275         return NULL;
 276 }
 277
 278
 279 /**
 280  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 281  * @idx: index
 282  * @sdata: local subif, or NULL for all entries
 283  *
 284  * Returns: pointer to the mesh path structure, or NULL if not found.
 285  *
 286  * Locking: must be called within a read rcu section.
 287  */
 288 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 289 {
 290         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 291         struct mpath_node *node;
 292         struct hlist_node *p;
 293         int i;
 294         int j = 0;
 295
 296         for_each_mesh_entry(tbl, p, node, i) {
 297                 if (sdata && node->mpath->sdata != sdata)
 298                         continue;
 299                 if (j++ == idx) {
 300                         if (MPATH_EXPIRED(node->mpath)) {
 301                                 spin_lock_bh(&node->mpath->state_lock);
 302                                 if (MPATH_EXPIRED(node->mpath))
 303                                         node->mpath->flags &= ~MESH_PATH_ACTIVE;
 304                                 spin_unlock_bh(&node->mpath->state_lock);
 305                         }
 306                         return node->mpath;
 307                 }
 308         }
 309
 310         return NULL;
 311 }
 312
 313 /**
 314  * mesh_path_add - allocate and add a new path to the mesh path table
 315  * @addr: destination address of the path (ETH_ALEN length)
 316  * @sdata: local subif
 317  *
 318  * Returns: 0 on success
 319  *
 320  * State: the initial state of the new path is set to 0
 321  */
 322 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 323 {
 324         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 325         struct ieee80211_local *local = sdata->local;
 326         struct mesh_table *tbl;
 327         struct mesh_path *mpath, *new_mpath;
 328         struct mpath_node *node, *new_node;
 329         struct hlist_head *bucket;
 330         struct hlist_node *n;
 331         int grow = 0;
 332         int err = 0;
 333         u32 hash_idx;
 334
 335         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 336                 /* never add ourselves as neighbours */
 337                 return -ENOTSUPP;
 338
 339         if (is_multicast_ether_addr(dst))
 340                 return -ENOTSUPP;
 341
 342         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 343                 return -ENOSPC;
 344
 345         err = -ENOMEM;
 346         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 347         if (!new_mpath)
 348                 goto err_path_alloc;
 349
 350         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 351         if (!new_node)
 352                 goto err_node_alloc;
 353
 354         read_lock_bh(&pathtbl_resize_lock);
 355         memcpy(new_mpath->dst, dst, ETH_ALEN);
 356         new_mpath->sdata = sdata;
 357         new_mpath->flags = 0;
 358         skb_queue_head_init(&new_mpath->frame_queue);
 359         new_node->mpath = new_mpath;
 360         new_mpath->timer.data = (unsigned long) new_mpath;
 361         new_mpath->timer.function = mesh_path_timer;
 362         new_mpath->exp_time = jiffies;
 363         spin_lock_init(&new_mpath->state_lock);
 364         init_timer(&new_mpath->timer);
 365
 366         tbl = resize_dereference_mesh_paths();
 367
 368         hash_idx = mesh_table_hash(dst, sdata, tbl);
 369         bucket = &tbl->hash_buckets[hash_idx];
 370
 371         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 372
 373         err = -EEXIST;
 374         hlist_for_each_entry(node, n, bucket, list) {
 375                 mpath = node->mpath;
 376                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 377                         goto err_exists;
 378         }
 379
 380         hlist_add_head_rcu(&new_node->list, bucket);
 381         if (atomic_inc_return(&tbl->entries) >=
 382             tbl->mean_chain_len * (tbl->hash_mask + 1))
 383                 grow = 1;
 384
 385         mesh_paths_generation++;
 386
 387         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 388         read_unlock_bh(&pathtbl_resize_lock);
 389         if (grow) {
 390                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 391                 ieee80211_queue_work(&local->hw, &sdata->work);
 392         }
 393         return 0;
 394
 395 err_exists:
 396         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 397         read_unlock_bh(&pathtbl_resize_lock);
 398         kfree(new_node);
 399 err_node_alloc:
 400         kfree(new_mpath);
 401 err_path_alloc:
 402         atomic_dec(&sdata->u.mesh.mpaths);
 403         return err;
 404 }
 405
 406 static void mesh_table_free_rcu(struct rcu_head *rcu)
 407 {
 408         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 409
 410         mesh_table_free(tbl, false);
 411 }
 412
 413 void mesh_mpath_table_grow(void)
 414 {
 415         struct mesh_table *oldtbl, *newtbl;
 416
 417         write_lock_bh(&pathtbl_resize_lock);
 418         oldtbl = resize_dereference_mesh_paths();
 419         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 420         if (!newtbl)
 421                 goto out;
 422         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 423                 __mesh_table_free(newtbl);
 424                 goto out;
 425         }
 426         rcu_assign_pointer(mesh_paths, newtbl);
 427
 428         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 429
 430  out:
 431         write_unlock_bh(&pathtbl_resize_lock);
 432 }
 433
 434 void mesh_mpp_table_grow(void)
 435 {
 436         struct mesh_table *oldtbl, *newtbl;
 437
 438         write_lock_bh(&pathtbl_resize_lock);
 439         oldtbl = resize_dereference_mpp_paths();
 440         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 441         if (!newtbl)
 442                 goto out;
 443         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 444                 __mesh_table_free(newtbl);
 445                 goto out;
 446         }
 447         rcu_assign_pointer(mpp_paths, newtbl);
 448         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 449
 450  out:
 451         write_unlock_bh(&pathtbl_resize_lock);
 452 }
 453
 454 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 455 {
 456         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 457         struct ieee80211_local *local = sdata->local;
 458         struct mesh_table *tbl;
 459         struct mesh_path *mpath, *new_mpath;
 460         struct mpath_node *node, *new_node;
 461         struct hlist_head *bucket;
 462         struct hlist_node *n;
 463         int grow = 0;
 464         int err = 0;
 465         u32 hash_idx;
 466
 467         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 468                 /* never add ourselves as neighbours */
 469                 return -ENOTSUPP;
 470
 471         if (is_multicast_ether_addr(dst))
 472                 return -ENOTSUPP;
 473
 474         err = -ENOMEM;
 475         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 476         if (!new_mpath)
 477                 goto err_path_alloc;
 478
 479         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 480         if (!new_node)
 481                 goto err_node_alloc;
 482
 483         read_lock_bh(&pathtbl_resize_lock);
 484         memcpy(new_mpath->dst, dst, ETH_ALEN);
 485         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 486         new_mpath->sdata = sdata;
 487         new_mpath->flags = 0;
 488         skb_queue_head_init(&new_mpath->frame_queue);
 489         new_node->mpath = new_mpath;
 490         new_mpath->exp_time = jiffies;
 491         spin_lock_init(&new_mpath->state_lock);
 492
 493         tbl = resize_dereference_mpp_paths();
 494
 495         hash_idx = mesh_table_hash(dst, sdata, tbl);
 496         bucket = &tbl->hash_buckets[hash_idx];
 497
 498         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 499
 500         err = -EEXIST;
 501         hlist_for_each_entry(node, n, bucket, list) {
 502                 mpath = node->mpath;
 503                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 504                         goto err_exists;
 505         }
 506
 507         hlist_add_head_rcu(&new_node->list, bucket);
 508         if (atomic_inc_return(&tbl->entries) >=
 509             tbl->mean_chain_len * (tbl->hash_mask + 1))
 510                 grow = 1;
 511
 512         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 513         read_unlock_bh(&pathtbl_resize_lock);
 514         if (grow) {
 515                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 516                 ieee80211_queue_work(&local->hw, &sdata->work);
 517         }
 518         return 0;
 519
 520 err_exists:
 521         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 522         read_unlock_bh(&pathtbl_resize_lock);
 523         kfree(new_node);
 524 err_node_alloc:
 525         kfree(new_mpath);
 526 err_path_alloc:
 527         return err;
 528 }
 529
 530
 531 /**
 532  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 533  *
 534  * @sta: broken peer link
 535  *
 536  * This function must be called from the rate control algorithm if enough
 537  * delivery errors suggest that a peer link is no longer usable.
 538  */
 539 void mesh_plink_broken(struct sta_info *sta)
 540 {
 541         struct mesh_table *tbl;
 542         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 543         struct mesh_path *mpath;
 544         struct mpath_node *node;
 545         struct hlist_node *p;
 546         struct ieee80211_sub_if_data *sdata = sta->sdata;
 547         int i;
 548         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 549
 550         rcu_read_lock();
 551         tbl = rcu_dereference(mesh_paths);
 552         for_each_mesh_entry(tbl, p, node, i) {
 553                 mpath = node->mpath;
 554                 spin_lock_bh(&mpath->state_lock);
 555                 if (rcu_dereference(mpath->next_hop) == sta &&
 556                     mpath->flags & MESH_PATH_ACTIVE &&
 557                     !(mpath->flags & MESH_PATH_FIXED)) {
 558                         mpath->flags &= ~MESH_PATH_ACTIVE;
 559                         ++mpath->sn;
 560                         spin_unlock_bh(&mpath->state_lock);
 561                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 562                                         mpath->dst, cpu_to_le32(mpath->sn),
 563                                         reason, bcast, sdata);
 564                 } else
 565                 spin_unlock_bh(&mpath->state_lock);
 566         }
 567         rcu_read_unlock();
 568 }
 569
 570 /**
 571  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 572  *
 573  * @sta - mesh peer to match
 574  *
 575  * RCU notes: this function is called when a mesh plink transitions from
 576  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 577  * allows path creation. This will happen before the sta can be freed (because
 578  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 579  * protected against the plink disappearing.
 580  */
 581 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 582 {
 583         struct mesh_table *tbl;
 584         struct mesh_path *mpath;
 585         struct mpath_node *node;
 586         struct hlist_node *p;
 587         int i;
 588
 589         rcu_read_lock();
 590         tbl = rcu_dereference(mesh_paths);
 591         for_each_mesh_entry(tbl, p, node, i) {
 592                 mpath = node->mpath;
 593                 if (rcu_dereference(mpath->next_hop) == sta)
 594                         mesh_path_del(mpath->dst, mpath->sdata);
 595         }
 596         rcu_read_unlock();
 597 }
 598
 599 void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
 600 {
 601         struct mesh_table *tbl;
 602         struct mesh_path *mpath;
 603         struct mpath_node *node;
 604         struct hlist_node *p;
 605         int i;
 606
 607         rcu_read_lock();
 608         tbl = rcu_dereference(mesh_paths);
 609         for_each_mesh_entry(tbl, p, node, i) {
 610                 mpath = node->mpath;
 611                 if (mpath->sdata == sdata)
 612                         mesh_path_del(mpath->dst, mpath->sdata);
 613         }
 614         rcu_read_unlock();
 615 }
 616
 617 static void mesh_path_node_reclaim(struct rcu_head *rp)
 618 {
 619         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 620         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 621
 622         if (node->mpath->timer.function)
 623                 del_timer_sync(&node->mpath->timer);
 624         atomic_dec(&sdata->u.mesh.mpaths);
 625         kfree(node->mpath);
 626         kfree(node);
 627 }
 628
 629 /**
 630  * mesh_path_del - delete a mesh path from the table
 631  *
 632  * @addr: dst address (ETH_ALEN length)
 633  * @sdata: local subif
 634  *
 635  * Returns: 0 if successful
 636  */
 637 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 638 {
 639         struct mesh_table *tbl;
 640         struct mesh_path *mpath;
 641         struct mpath_node *node;
 642         struct hlist_head *bucket;
 643         struct hlist_node *n;
 644         int hash_idx;
 645         int err = 0;
 646
 647         read_lock_bh(&pathtbl_resize_lock);
 648         tbl = resize_dereference_mesh_paths();
 649         hash_idx = mesh_table_hash(addr, sdata, tbl);
 650         bucket = &tbl->hash_buckets[hash_idx];
 651
 652         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 653         hlist_for_each_entry(node, n, bucket, list) {
 654                 mpath = node->mpath;
 655                 if (mpath->sdata == sdata &&
 656                     memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
 657                         spin_lock_bh(&mpath->state_lock);
 658                         mpath->flags |= MESH_PATH_RESOLVING;
 659                         hlist_del_rcu(&node->list);
 660                         call_rcu(&node->rcu, mesh_path_node_reclaim);
 661                         atomic_dec(&tbl->entries);
 662                         spin_unlock_bh(&mpath->state_lock);
 663                         goto enddel;
 664                 }
 665         }
 666
 667         err = -ENXIO;
 668 enddel:
 669         mesh_paths_generation++;
 670         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 671         read_unlock_bh(&pathtbl_resize_lock);
 672         return err;
 673 }
 674
 675 /**
 676  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 677  *
 678  * @mpath: mesh path to activate
 679  *
 680  * Locking: the state_lock of the mpath structure must NOT be held when calling
 681  * this function.
 682  */
 683 void mesh_path_tx_pending(struct mesh_path *mpath)
 684 {
 685         if (mpath->flags & MESH_PATH_ACTIVE)
 686                 ieee80211_add_pending_skbs(mpath->sdata->local,
 687                                 &mpath->frame_queue);
 688 }
 689
 690 /**
 691  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 692  *
 693  * @skb: frame to discard
 694  * @sdata: network subif the frame was to be sent through
 695  *
 696  * If the frame was being forwarded from another MP, a PERR frame will be sent
 697  * to the precursor.  The precursor's address (i.e. the previous hop) was saved
 698  * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
 699  * the destination is successfully resolved.
 700  *
 701  * Locking: the function must me called within a rcu_read_lock region
 702  */
 703 void mesh_path_discard_frame(struct sk_buff *skb,
 704                              struct ieee80211_sub_if_data *sdata)
 705 {
 706         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 707         struct mesh_path *mpath;
 708         u32 sn = 0;
 709         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_NOFORWARD);
 710
 711         if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
 712                 u8 *ra, *da;
 713
 714                 da = hdr->addr3;
 715                 ra = hdr->addr1;
 716                 mpath = mesh_path_lookup(da, sdata);
 717                 if (mpath)
 718                         sn = ++mpath->sn;
 719                 mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, skb->data,
 720                                    cpu_to_le32(sn), reason, ra, sdata);
 721         }
 722
 723         kfree_skb(skb);
 724         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 725 }
 726
 727 /**
 728  * mesh_path_flush_pending - free the pending queue of a mesh path
 729  *
 730  * @mpath: mesh path whose queue has to be freed
 731  *
 732  * Locking: the function must me called within a rcu_read_lock region
 733  */
 734 void mesh_path_flush_pending(struct mesh_path *mpath)
 735 {
 736         struct sk_buff *skb;
 737
 738         while ((skb = skb_dequeue(&mpath->frame_queue)) &&
 739                         (mpath->flags & MESH_PATH_ACTIVE))
 740                 mesh_path_discard_frame(skb, mpath->sdata);
 741 }
 742
 743 /**
 744  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 745  *
 746  * @mpath: the mesh path to modify
 747  * @next_hop: the next hop to force
 748  *
 749  * Locking: this function must be called holding mpath->state_lock
 750  */
 751 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 752 {
 753         spin_lock_bh(&mpath->state_lock);
 754         mesh_path_assign_nexthop(mpath, next_hop);
 755         mpath->sn = 0xffff;
 756         mpath->metric = 0;
 757         mpath->hop_count = 0;
 758         mpath->exp_time = 0;
 759         mpath->flags |= MESH_PATH_FIXED;
 760         mesh_path_activate(mpath);
 761         spin_unlock_bh(&mpath->state_lock);
 762         mesh_path_tx_pending(mpath);
 763 }
 764
 765 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
 766 {
 767         struct mesh_path *mpath;
 768         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
 769         mpath = node->mpath;
 770         hlist_del_rcu(p);
 771         if (free_leafs) {
 772                 if (mpath->timer.function)
 773                         del_timer_sync(&mpath->timer);
 774                 kfree(mpath);
 775         }
 776         kfree(node);
 777 }
 778
 779 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
 780 {
 781         struct mesh_path *mpath;
 782         struct mpath_node *node, *new_node;
 783         u32 hash_idx;
 784
 785         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 786         if (new_node == NULL)
 787                 return -ENOMEM;
 788
 789         node = hlist_entry(p, struct mpath_node, list);
 790         mpath = node->mpath;
 791         new_node->mpath = mpath;
 792         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
 793         hlist_add_head(&new_node->list,
 794                         &newtbl->hash_buckets[hash_idx]);
 795         return 0;
 796 }
 797
 798 int mesh_pathtbl_init(void)
 799 {
 800         struct mesh_table *tbl_path, *tbl_mpp;
 801
 802         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 803         if (!tbl_path)
 804                 return -ENOMEM;
 805         tbl_path->free_node = &mesh_path_node_free;
 806         tbl_path->copy_node = &mesh_path_node_copy;
 807         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
 808
 809         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 810         if (!tbl_mpp) {
 811                 mesh_table_free(tbl_path, true);
 812                 return -ENOMEM;
 813         }
 814         tbl_mpp->free_node = &mesh_path_node_free;
 815         tbl_mpp->copy_node = &mesh_path_node_copy;
 816         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
 817
 818         /* Need no locking since this is during init */
 819         RCU_INIT_POINTER(mesh_paths, tbl_path);
 820         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
 821
 822         return 0;
 823 }
 824
 825 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 826 {
 827         struct mesh_table *tbl;
 828         struct mesh_path *mpath;
 829         struct mpath_node *node;
 830         struct hlist_node *p;
 831         int i;
 832
 833         rcu_read_lock();
 834         tbl = rcu_dereference(mesh_paths);
 835         for_each_mesh_entry(tbl, p, node, i) {
 836                 if (node->mpath->sdata != sdata)
 837                         continue;
 838                 mpath = node->mpath;
 839                 spin_lock_bh(&mpath->state_lock);
 840                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 841                     (!(mpath->flags & MESH_PATH_FIXED)) &&
 842                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE)) {
 843                         spin_unlock_bh(&mpath->state_lock);
 844                         mesh_path_del(mpath->dst, mpath->sdata);
 845                 } else
 846                         spin_unlock_bh(&mpath->state_lock);
 847         }
 848         rcu_read_unlock();
 849 }
 850
 851 void mesh_pathtbl_unregister(void)
 852 {
 853         /* no need for locking during exit path */
 854         mesh_table_free(rcu_dereference_raw(mesh_paths), true);
 855         mesh_table_free(rcu_dereference_raw(mpp_paths), true);
 856 }