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