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 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  21 #define INIT_PATHS_SIZE_ORDER   2
  22
  23 /* Keep the mean chain length below this constant */
  24 #define MEAN_CHAIN_LEN          2
  25
  26 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  27                                 time_after(jiffies, mpath->exp_time) && \
  28                                 !(mpath->flags & MESH_PATH_FIXED))
  29
  30 struct mpath_node {
  31         struct hlist_node list;
  32         struct rcu_head rcu;
  33         /* This indirection allows two different tables to point to the same
  34          * mesh_path structure, useful when resizing
  35          */
  36         struct mesh_path *mpath;
  37 };
  38
  39 static struct mesh_table *mesh_paths;
  40 static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
  41
  42 int mesh_paths_generation;
  43
  44 /* This lock will have the grow table function as writer and add / delete nodes
  45  * as readers. When reading the table (i.e. doing lookups) we are well protected
  46  * by RCU
  47  */
  48 static DEFINE_RWLOCK(pathtbl_resize_lock);
  49
  50
  51 static struct mesh_table *mesh_table_alloc(int size_order)
  52 {
  53         int i;
  54         struct mesh_table *newtbl;
  55
  56         newtbl = kmalloc(sizeof(struct mesh_table), GFP_KERNEL);
  57         if (!newtbl)
  58                 return NULL;
  59
  60         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  61                         (1 << size_order), GFP_KERNEL);
  62
  63         if (!newtbl->hash_buckets) {
  64                 kfree(newtbl);
  65                 return NULL;
  66         }
  67
  68         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  69                         (1 << size_order), GFP_KERNEL);
  70         if (!newtbl->hashwlock) {
  71                 kfree(newtbl->hash_buckets);
  72                 kfree(newtbl);
  73                 return NULL;
  74         }
  75
  76         newtbl->size_order = size_order;
  77         newtbl->hash_mask = (1 << size_order) - 1;
  78         atomic_set(&newtbl->entries,  0);
  79         get_random_bytes(&newtbl->hash_rnd,
  80                         sizeof(newtbl->hash_rnd));
  81         for (i = 0; i <= newtbl->hash_mask; i++)
  82                 spin_lock_init(&newtbl->hashwlock[i]);
  83
  84         return newtbl;
  85 }
  86
  87 static void __mesh_table_free(struct mesh_table *tbl)
  88 {
  89         kfree(tbl->hash_buckets);
  90         kfree(tbl->hashwlock);
  91         kfree(tbl);
  92 }
  93
  94 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
  95 {
  96         struct hlist_head *mesh_hash;
  97         struct hlist_node *p, *q;
  98         int i;
  99
 100         mesh_hash = tbl->hash_buckets;
 101         for (i = 0; i <= tbl->hash_mask; i++) {
 102                 spin_lock_bh(&tbl->hashwlock[i]);
 103                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 104                         tbl->free_node(p, free_leafs);
 105                         atomic_dec(&tbl->entries);
 106                 }
 107                 spin_unlock_bh(&tbl->hashwlock[i]);
 108         }
 109         __mesh_table_free(tbl);
 110 }
 111
 112 static int mesh_table_grow(struct mesh_table *oldtbl,
 113                            struct mesh_table *newtbl)
 114 {
 115         struct hlist_head *oldhash;
 116         struct hlist_node *p, *q;
 117         int i;
 118
 119         if (atomic_read(&oldtbl->entries)
 120                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 121                 return -EAGAIN;
 122
 123         newtbl->free_node = oldtbl->free_node;
 124         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 125         newtbl->copy_node = oldtbl->copy_node;
 126         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 127
 128         oldhash = oldtbl->hash_buckets;
 129         for (i = 0; i <= oldtbl->hash_mask; i++)
 130                 hlist_for_each(p, &oldhash[i])
 131                         if (oldtbl->copy_node(p, newtbl) < 0)
 132                                 goto errcopy;
 133
 134         return 0;
 135
 136 errcopy:
 137         for (i = 0; i <= newtbl->hash_mask; i++) {
 138                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 139                         oldtbl->free_node(p, 0);
 140         }
 141         return -ENOMEM;
 142 }
 143
 144 static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
 145                            struct mesh_table *tbl)
 146 {
 147         /* Use last four bytes of hw addr and interface index as hash index */
 148         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
 149                 & tbl->hash_mask;
 150 }
 151
 152
 153 /**
 154  *
 155  * mesh_path_assign_nexthop - update mesh path next hop
 156  *
 157  * @mpath: mesh path to update
 158  * @sta: next hop to assign
 159  *
 160  * Locking: mpath->state_lock must be held when calling this function
 161  */
 162 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 163 {
 164         struct sk_buff *skb;
 165         struct ieee80211_hdr *hdr;
 166         struct sk_buff_head tmpq;
 167         unsigned long flags;
 168
 169         rcu_assign_pointer(mpath->next_hop, sta);
 170
 171         __skb_queue_head_init(&tmpq);
 172
 173         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 174
 175         while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
 176                 hdr = (struct ieee80211_hdr *) skb->data;
 177                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 178                 __skb_queue_tail(&tmpq, skb);
 179         }
 180
 181         skb_queue_splice(&tmpq, &mpath->frame_queue);
 182         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 183 }
 184
 185
 186 /**
 187  * mesh_path_lookup - look up a path in the mesh path table
 188  * @dst: hardware address (ETH_ALEN length) of destination
 189  * @sdata: local subif
 190  *
 191  * Returns: pointer to the mesh path structure, or NULL if not found
 192  *
 193  * Locking: must be called within a read rcu section.
 194  */
 195 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 196 {
 197         struct mesh_path *mpath;
 198         struct hlist_node *n;
 199         struct hlist_head *bucket;
 200         struct mesh_table *tbl;
 201         struct mpath_node *node;
 202
 203         tbl = rcu_dereference(mesh_paths);
 204
 205         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 206         hlist_for_each_entry_rcu(node, n, bucket, list) {
 207                 mpath = node->mpath;
 208                 if (mpath->sdata == sdata &&
 209                                 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 210                         if (MPATH_EXPIRED(mpath)) {
 211                                 spin_lock_bh(&mpath->state_lock);
 212                                 if (MPATH_EXPIRED(mpath))
 213                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 214                                 spin_unlock_bh(&mpath->state_lock);
 215                         }
 216                         return mpath;
 217                 }
 218         }
 219         return NULL;
 220 }
 221
 222 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 223 {
 224         struct mesh_path *mpath;
 225         struct hlist_node *n;
 226         struct hlist_head *bucket;
 227         struct mesh_table *tbl;
 228         struct mpath_node *node;
 229
 230         tbl = rcu_dereference(mpp_paths);
 231
 232         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 233         hlist_for_each_entry_rcu(node, n, bucket, list) {
 234                 mpath = node->mpath;
 235                 if (mpath->sdata == sdata &&
 236                     memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 237                         if (MPATH_EXPIRED(mpath)) {
 238                                 spin_lock_bh(&mpath->state_lock);
 239                                 if (MPATH_EXPIRED(mpath))
 240                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 241                                 spin_unlock_bh(&mpath->state_lock);
 242                         }
 243                         return mpath;
 244                 }
 245         }
 246         return NULL;
 247 }
 248
 249
 250 /**
 251  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 252  * @idx: index
 253  * @sdata: local subif, or NULL for all entries
 254  *
 255  * Returns: pointer to the mesh path structure, or NULL if not found.
 256  *
 257  * Locking: must be called within a read rcu section.
 258  */
 259 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 260 {
 261         struct mpath_node *node;
 262         struct hlist_node *p;
 263         int i;
 264         int j = 0;
 265
 266         for_each_mesh_entry(mesh_paths, p, node, i) {
 267                 if (sdata && node->mpath->sdata != sdata)
 268                         continue;
 269                 if (j++ == idx) {
 270                         if (MPATH_EXPIRED(node->mpath)) {
 271                                 spin_lock_bh(&node->mpath->state_lock);
 272                                 if (MPATH_EXPIRED(node->mpath))
 273                                         node->mpath->flags &= ~MESH_PATH_ACTIVE;
 274                                 spin_unlock_bh(&node->mpath->state_lock);
 275                         }
 276                         return node->mpath;
 277                 }
 278         }
 279
 280         return NULL;
 281 }
 282
 283 /**
 284  * mesh_path_add - allocate and add a new path to the mesh path table
 285  * @addr: destination address of the path (ETH_ALEN length)
 286  * @sdata: local subif
 287  *
 288  * Returns: 0 on success
 289  *
 290  * State: the initial state of the new path is set to 0
 291  */
 292 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 293 {
 294         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 295         struct ieee80211_local *local = sdata->local;
 296         struct mesh_path *mpath, *new_mpath;
 297         struct mpath_node *node, *new_node;
 298         struct hlist_head *bucket;
 299         struct hlist_node *n;
 300         int grow = 0;
 301         int err = 0;
 302         u32 hash_idx;
 303
 304         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 305                 /* never add ourselves as neighbours */
 306                 return -ENOTSUPP;
 307
 308         if (is_multicast_ether_addr(dst))
 309                 return -ENOTSUPP;
 310
 311         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 312                 return -ENOSPC;
 313
 314         err = -ENOMEM;
 315         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 316         if (!new_mpath)
 317                 goto err_path_alloc;
 318
 319         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 320         if (!new_node)
 321                 goto err_node_alloc;
 322
 323         read_lock_bh(&pathtbl_resize_lock);
 324         memcpy(new_mpath->dst, dst, ETH_ALEN);
 325         new_mpath->sdata = sdata;
 326         new_mpath->flags = 0;
 327         skb_queue_head_init(&new_mpath->frame_queue);
 328         new_node->mpath = new_mpath;
 329         new_mpath->timer.data = (unsigned long) new_mpath;
 330         new_mpath->timer.function = mesh_path_timer;
 331         new_mpath->exp_time = jiffies;
 332         spin_lock_init(&new_mpath->state_lock);
 333         init_timer(&new_mpath->timer);
 334
 335         hash_idx = mesh_table_hash(dst, sdata, mesh_paths);
 336         bucket = &mesh_paths->hash_buckets[hash_idx];
 337
 338         spin_lock_bh(&mesh_paths->hashwlock[hash_idx]);
 339
 340         err = -EEXIST;
 341         hlist_for_each_entry(node, n, bucket, list) {
 342                 mpath = node->mpath;
 343                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 344                         goto err_exists;
 345         }
 346
 347         hlist_add_head_rcu(&new_node->list, bucket);
 348         if (atomic_inc_return(&mesh_paths->entries) >=
 349                 mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
 350                 grow = 1;
 351
 352         mesh_paths_generation++;
 353
 354         spin_unlock_bh(&mesh_paths->hashwlock[hash_idx]);
 355         read_unlock_bh(&pathtbl_resize_lock);
 356         if (grow) {
 357                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 358                 ieee80211_queue_work(&local->hw, &sdata->work);
 359         }
 360         return 0;
 361
 362 err_exists:
 363         spin_unlock_bh(&mesh_paths->hashwlock[hash_idx]);
 364         read_unlock_bh(&pathtbl_resize_lock);
 365         kfree(new_node);
 366 err_node_alloc:
 367         kfree(new_mpath);
 368 err_path_alloc:
 369         atomic_dec(&sdata->u.mesh.mpaths);
 370         return err;
 371 }
 372
 373 void mesh_mpath_table_grow(void)
 374 {
 375         struct mesh_table *oldtbl, *newtbl;
 376
 377         rcu_read_lock();
 378         newtbl = mesh_table_alloc(rcu_dereference(mesh_paths)->size_order + 1);
 379         if (!newtbl)
 380                 return;
 381         write_lock_bh(&pathtbl_resize_lock);
 382         oldtbl = mesh_paths;
 383         if (mesh_table_grow(mesh_paths, newtbl) < 0) {
 384                 rcu_read_unlock();
 385                 __mesh_table_free(newtbl);
 386                 write_unlock_bh(&pathtbl_resize_lock);
 387                 return;
 388         }
 389         rcu_read_unlock();
 390         rcu_assign_pointer(mesh_paths, newtbl);
 391         write_unlock_bh(&pathtbl_resize_lock);
 392
 393         synchronize_rcu();
 394         mesh_table_free(oldtbl, false);
 395 }
 396
 397 void mesh_mpp_table_grow(void)
 398 {
 399         struct mesh_table *oldtbl, *newtbl;
 400
 401         rcu_read_lock();
 402         newtbl = mesh_table_alloc(rcu_dereference(mpp_paths)->size_order + 1);
 403         if (!newtbl)
 404                 return;
 405         write_lock_bh(&pathtbl_resize_lock);
 406         oldtbl = mpp_paths;
 407         if (mesh_table_grow(mpp_paths, newtbl) < 0) {
 408                 rcu_read_unlock();
 409                 __mesh_table_free(newtbl);
 410                 write_unlock_bh(&pathtbl_resize_lock);
 411                 return;
 412         }
 413         rcu_read_unlock();
 414         rcu_assign_pointer(mpp_paths, newtbl);
 415         write_unlock_bh(&pathtbl_resize_lock);
 416
 417         synchronize_rcu();
 418         mesh_table_free(oldtbl, false);
 419 }
 420
 421 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 422 {
 423         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 424         struct ieee80211_local *local = sdata->local;
 425         struct mesh_path *mpath, *new_mpath;
 426         struct mpath_node *node, *new_node;
 427         struct hlist_head *bucket;
 428         struct hlist_node *n;
 429         int grow = 0;
 430         int err = 0;
 431         u32 hash_idx;
 432
 433         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 434                 /* never add ourselves as neighbours */
 435                 return -ENOTSUPP;
 436
 437         if (is_multicast_ether_addr(dst))
 438                 return -ENOTSUPP;
 439
 440         err = -ENOMEM;
 441         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 442         if (!new_mpath)
 443                 goto err_path_alloc;
 444
 445         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 446         if (!new_node)
 447                 goto err_node_alloc;
 448
 449         read_lock_bh(&pathtbl_resize_lock);
 450         memcpy(new_mpath->dst, dst, ETH_ALEN);
 451         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 452         new_mpath->sdata = sdata;
 453         new_mpath->flags = 0;
 454         skb_queue_head_init(&new_mpath->frame_queue);
 455         new_node->mpath = new_mpath;
 456         new_mpath->exp_time = jiffies;
 457         spin_lock_init(&new_mpath->state_lock);
 458
 459         hash_idx = mesh_table_hash(dst, sdata, mpp_paths);
 460         bucket = &mpp_paths->hash_buckets[hash_idx];
 461
 462         spin_lock_bh(&mpp_paths->hashwlock[hash_idx]);
 463
 464         err = -EEXIST;
 465         hlist_for_each_entry(node, n, bucket, list) {
 466                 mpath = node->mpath;
 467                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 468                         goto err_exists;
 469         }
 470
 471         hlist_add_head_rcu(&new_node->list, bucket);
 472         if (atomic_inc_return(&mpp_paths->entries) >=
 473                 mpp_paths->mean_chain_len * (mpp_paths->hash_mask + 1))
 474                 grow = 1;
 475
 476         spin_unlock_bh(&mpp_paths->hashwlock[hash_idx]);
 477         read_unlock_bh(&pathtbl_resize_lock);
 478         if (grow) {
 479                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 480                 ieee80211_queue_work(&local->hw, &sdata->work);
 481         }
 482         return 0;
 483
 484 err_exists:
 485         spin_unlock_bh(&mpp_paths->hashwlock[hash_idx]);
 486         read_unlock_bh(&pathtbl_resize_lock);
 487         kfree(new_node);
 488 err_node_alloc:
 489         kfree(new_mpath);
 490 err_path_alloc:
 491         return err;
 492 }
 493
 494
 495 /**
 496  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 497  *
 498  * @sta: broken peer link
 499  *
 500  * This function must be called from the rate control algorithm if enough
 501  * delivery errors suggest that a peer link is no longer usable.
 502  */
 503 void mesh_plink_broken(struct sta_info *sta)
 504 {
 505         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 506         struct mesh_path *mpath;
 507         struct mpath_node *node;
 508         struct hlist_node *p;
 509         struct ieee80211_sub_if_data *sdata = sta->sdata;
 510         int i;
 511
 512         rcu_read_lock();
 513         for_each_mesh_entry(mesh_paths, p, node, i) {
 514                 mpath = node->mpath;
 515                 spin_lock_bh(&mpath->state_lock);
 516                 if (mpath->next_hop == sta &&
 517                     mpath->flags & MESH_PATH_ACTIVE &&
 518                     !(mpath->flags & MESH_PATH_FIXED)) {
 519                         mpath->flags &= ~MESH_PATH_ACTIVE;
 520                         ++mpath->sn;
 521                         spin_unlock_bh(&mpath->state_lock);
 522                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 523                                         mpath->dst, cpu_to_le32(mpath->sn),
 524                                         cpu_to_le16(PERR_RCODE_DEST_UNREACH),
 525                                         bcast, sdata);
 526                 } else
 527                 spin_unlock_bh(&mpath->state_lock);
 528         }
 529         rcu_read_unlock();
 530 }
 531
 532 /**
 533  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 534  *
 535  * @sta - mesh peer to match
 536  *
 537  * RCU notes: this function is called when a mesh plink transitions from
 538  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 539  * allows path creation. This will happen before the sta can be freed (because
 540  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 541  * protected against the plink disappearing.
 542  */
 543 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 544 {
 545         struct mesh_path *mpath;
 546         struct mpath_node *node;
 547         struct hlist_node *p;
 548         int i;
 549
 550         for_each_mesh_entry(mesh_paths, p, node, i) {
 551                 mpath = node->mpath;
 552                 if (mpath->next_hop == sta)
 553                         mesh_path_del(mpath->dst, mpath->sdata);
 554         }
 555 }
 556
 557 void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
 558 {
 559         struct mesh_path *mpath;
 560         struct mpath_node *node;
 561         struct hlist_node *p;
 562         int i;
 563
 564         for_each_mesh_entry(mesh_paths, p, node, i) {
 565                 mpath = node->mpath;
 566                 if (mpath->sdata == sdata)
 567                         mesh_path_del(mpath->dst, mpath->sdata);
 568         }
 569 }
 570
 571 static void mesh_path_node_reclaim(struct rcu_head *rp)
 572 {
 573         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 574         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 575
 576         del_timer_sync(&node->mpath->timer);
 577         atomic_dec(&sdata->u.mesh.mpaths);
 578         kfree(node->mpath);
 579         kfree(node);
 580 }
 581
 582 /**
 583  * mesh_path_del - delete a mesh path from the table
 584  *
 585  * @addr: dst address (ETH_ALEN length)
 586  * @sdata: local subif
 587  *
 588  * Returns: 0 if successful
 589  */
 590 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 591 {
 592         struct mesh_path *mpath;
 593         struct mpath_node *node;
 594         struct hlist_head *bucket;
 595         struct hlist_node *n;
 596         int hash_idx;
 597         int err = 0;
 598
 599         read_lock_bh(&pathtbl_resize_lock);
 600         hash_idx = mesh_table_hash(addr, sdata, mesh_paths);
 601         bucket = &mesh_paths->hash_buckets[hash_idx];
 602
 603         spin_lock_bh(&mesh_paths->hashwlock[hash_idx]);
 604         hlist_for_each_entry(node, n, bucket, list) {
 605                 mpath = node->mpath;
 606                 if (mpath->sdata == sdata &&
 607                                 memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
 608                         spin_lock_bh(&mpath->state_lock);
 609                         mpath->flags |= MESH_PATH_RESOLVING;
 610                         hlist_del_rcu(&node->list);
 611                         call_rcu(&node->rcu, mesh_path_node_reclaim);
 612                         atomic_dec(&mesh_paths->entries);
 613                         spin_unlock_bh(&mpath->state_lock);
 614                         goto enddel;
 615                 }
 616         }
 617
 618         err = -ENXIO;
 619 enddel:
 620         mesh_paths_generation++;
 621         spin_unlock_bh(&mesh_paths->hashwlock[hash_idx]);
 622         read_unlock_bh(&pathtbl_resize_lock);
 623         return err;
 624 }
 625
 626 /**
 627  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 628  *
 629  * @mpath: mesh path to activate
 630  *
 631  * Locking: the state_lock of the mpath structure must NOT be held when calling
 632  * this function.
 633  */
 634 void mesh_path_tx_pending(struct mesh_path *mpath)
 635 {
 636         if (mpath->flags & MESH_PATH_ACTIVE)
 637                 ieee80211_add_pending_skbs(mpath->sdata->local,
 638                                 &mpath->frame_queue);
 639 }
 640
 641 /**
 642  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 643  *
 644  * @skb: frame to discard
 645  * @sdata: network subif the frame was to be sent through
 646  *
 647  * If the frame was being forwarded from another MP, a PERR frame will be sent
 648  * to the precursor.  The precursor's address (i.e. the previous hop) was saved
 649  * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
 650  * the destination is successfully resolved.
 651  *
 652  * Locking: the function must me called within a rcu_read_lock region
 653  */
 654 void mesh_path_discard_frame(struct sk_buff *skb,
 655                              struct ieee80211_sub_if_data *sdata)
 656 {
 657         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 658         struct mesh_path *mpath;
 659         u32 sn = 0;
 660
 661         if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
 662                 u8 *ra, *da;
 663
 664                 da = hdr->addr3;
 665                 ra = hdr->addr1;
 666                 mpath = mesh_path_lookup(da, sdata);
 667                 if (mpath)
 668                         sn = ++mpath->sn;
 669                 mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, skb->data,
 670                                    cpu_to_le32(sn),
 671                                    cpu_to_le16(PERR_RCODE_NO_ROUTE), ra, sdata);
 672         }
 673
 674         kfree_skb(skb);
 675         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 676 }
 677
 678 /**
 679  * mesh_path_flush_pending - free the pending queue of a mesh path
 680  *
 681  * @mpath: mesh path whose queue has to be freed
 682  *
 683  * Locking: the function must me called within a rcu_read_lock region
 684  */
 685 void mesh_path_flush_pending(struct mesh_path *mpath)
 686 {
 687         struct sk_buff *skb;
 688
 689         while ((skb = skb_dequeue(&mpath->frame_queue)) &&
 690                         (mpath->flags & MESH_PATH_ACTIVE))
 691                 mesh_path_discard_frame(skb, mpath->sdata);
 692 }
 693
 694 /**
 695  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 696  *
 697  * @mpath: the mesh path to modify
 698  * @next_hop: the next hop to force
 699  *
 700  * Locking: this function must be called holding mpath->state_lock
 701  */
 702 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 703 {
 704         spin_lock_bh(&mpath->state_lock);
 705         mesh_path_assign_nexthop(mpath, next_hop);
 706         mpath->sn = 0xffff;
 707         mpath->metric = 0;
 708         mpath->hop_count = 0;
 709         mpath->exp_time = 0;
 710         mpath->flags |= MESH_PATH_FIXED;
 711         mesh_path_activate(mpath);
 712         spin_unlock_bh(&mpath->state_lock);
 713         mesh_path_tx_pending(mpath);
 714 }
 715
 716 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
 717 {
 718         struct mesh_path *mpath;
 719         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
 720         mpath = node->mpath;
 721         hlist_del_rcu(p);
 722         if (free_leafs)
 723                 kfree(mpath);
 724         kfree(node);
 725 }
 726
 727 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
 728 {
 729         struct mesh_path *mpath;
 730         struct mpath_node *node, *new_node;
 731         u32 hash_idx;
 732
 733         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 734         if (new_node == NULL)
 735                 return -ENOMEM;
 736
 737         node = hlist_entry(p, struct mpath_node, list);
 738         mpath = node->mpath;
 739         new_node->mpath = mpath;
 740         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
 741         hlist_add_head(&new_node->list,
 742                         &newtbl->hash_buckets[hash_idx]);
 743         return 0;
 744 }
 745
 746 int mesh_pathtbl_init(void)
 747 {
 748         mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 749         if (!mesh_paths)
 750                 return -ENOMEM;
 751         mesh_paths->free_node = &mesh_path_node_free;
 752         mesh_paths->copy_node = &mesh_path_node_copy;
 753         mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
 754
 755         mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 756         if (!mpp_paths) {
 757                 mesh_table_free(mesh_paths, true);
 758                 return -ENOMEM;
 759         }
 760         mpp_paths->free_node = &mesh_path_node_free;
 761         mpp_paths->copy_node = &mesh_path_node_copy;
 762         mpp_paths->mean_chain_len = MEAN_CHAIN_LEN;
 763
 764         return 0;
 765 }
 766
 767 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 768 {
 769         struct mesh_path *mpath;
 770         struct mpath_node *node;
 771         struct hlist_node *p;
 772         int i;
 773
 774         read_lock_bh(&pathtbl_resize_lock);
 775         for_each_mesh_entry(mesh_paths, p, node, i) {
 776                 if (node->mpath->sdata != sdata)
 777                         continue;
 778                 mpath = node->mpath;
 779                 spin_lock_bh(&mpath->state_lock);
 780                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 781                     (!(mpath->flags & MESH_PATH_FIXED)) &&
 782                         time_after(jiffies,
 783                          mpath->exp_time + MESH_PATH_EXPIRE)) {
 784                         spin_unlock_bh(&mpath->state_lock);
 785                         mesh_path_del(mpath->dst, mpath->sdata);
 786                 } else
 787                         spin_unlock_bh(&mpath->state_lock);
 788         }
 789         read_unlock_bh(&pathtbl_resize_lock);
 790 }
 791
 792 void mesh_pathtbl_unregister(void)
 793 {
 794         mesh_table_free(mesh_paths, true);
 795         mesh_table_free(mpp_paths, true);
 796 }