net/mac80211/mesh_pathtbl.c

   1 /*
   2  * Copyright (c) 2008 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/spinlock.h>
  14 #include <linux/string.h>
  15 #include <net/mac80211.h>
  16 #include "ieee80211_i.h"
  17 #include "mesh.h"
  18
  19 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  20 #define INIT_PATHS_SIZE_ORDER   2
  21
  22 /* Keep the mean chain length below this constant */
  23 #define MEAN_CHAIN_LEN          2
  24
  25 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  26                                 time_after(jiffies, mpath->exp_time) && \
  27                                 !(mpath->flags & MESH_PATH_FIXED))
  28
  29 struct mpath_node {
  30         struct hlist_node list;
  31         struct rcu_head rcu;
  32         /* This indirection allows two different tables to point to the same
  33          * mesh_path structure, useful when resizing
  34          */
  35         struct mesh_path *mpath;
  36 };
  37
  38 static struct mesh_table *mesh_paths;
  39 static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
  40
  41 int mesh_paths_generation;
  42 static void __mesh_table_free(struct mesh_table *tbl)
  43 {
  44         kfree(tbl->hash_buckets);
  45         kfree(tbl->hashwlock);
  46         kfree(tbl);
  47 }
  48
  49 void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
  50 {
  51         struct hlist_head *mesh_hash;
  52         struct hlist_node *p, *q;
  53         int i;
  54
  55         mesh_hash = tbl->hash_buckets;
  56         for (i = 0; i <= tbl->hash_mask; i++) {
  57                 spin_lock(&tbl->hashwlock[i]);
  58                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
  59                         tbl->free_node(p, free_leafs);
  60                         atomic_dec(&tbl->entries);
  61                 }
  62                 spin_unlock(&tbl->hashwlock[i]);
  63         }
  64         __mesh_table_free(tbl);
  65 }
  66
  67 static struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
  68 {
  69         struct mesh_table *newtbl;
  70         struct hlist_head *oldhash;
  71         struct hlist_node *p, *q;
  72         int i;
  73
  74         if (atomic_read(&tbl->entries)
  75                         < tbl->mean_chain_len * (tbl->hash_mask + 1))
  76                 goto endgrow;
  77
  78         newtbl = mesh_table_alloc(tbl->size_order + 1);
  79         if (!newtbl)
  80                 goto endgrow;
  81
  82         newtbl->free_node = tbl->free_node;
  83         newtbl->mean_chain_len = tbl->mean_chain_len;
  84         newtbl->copy_node = tbl->copy_node;
  85         atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
  86
  87         oldhash = tbl->hash_buckets;
  88         for (i = 0; i <= tbl->hash_mask; i++)
  89                 hlist_for_each(p, &oldhash[i])
  90                         if (tbl->copy_node(p, newtbl) < 0)
  91                                 goto errcopy;
  92
  93         return newtbl;
  94
  95 errcopy:
  96         for (i = 0; i <= newtbl->hash_mask; i++) {
  97                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
  98                         tbl->free_node(p, 0);
  99         }
 100         __mesh_table_free(newtbl);
 101 endgrow:
 102         return NULL;
 103 }
 104
 105
 106 /* This lock will have the grow table function as writer and add / delete nodes
 107  * as readers. When reading the table (i.e. doing lookups) we are well protected
 108  * by RCU
 109  */
 110 static DEFINE_RWLOCK(pathtbl_resize_lock);
 111
 112 /**
 113  *
 114  * mesh_path_assign_nexthop - update mesh path next hop
 115  *
 116  * @mpath: mesh path to update
 117  * @sta: next hop to assign
 118  *
 119  * Locking: mpath->state_lock must be held when calling this function
 120  */
 121 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 122 {
 123         struct sk_buff *skb;
 124         struct ieee80211_hdr *hdr;
 125         struct sk_buff_head tmpq;
 126         unsigned long flags;
 127
 128         rcu_assign_pointer(mpath->next_hop, sta);
 129
 130         __skb_queue_head_init(&tmpq);
 131
 132         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 133
 134         while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
 135                 hdr = (struct ieee80211_hdr *) skb->data;
 136                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 137                 __skb_queue_tail(&tmpq, skb);
 138         }
 139
 140         skb_queue_splice(&tmpq, &mpath->frame_queue);
 141         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 142 }
 143
 144
 145 /**
 146  * mesh_path_lookup - look up a path in the mesh path table
 147  * @dst: hardware address (ETH_ALEN length) of destination
 148  * @sdata: local subif
 149  *
 150  * Returns: pointer to the mesh path structure, or NULL if not found
 151  *
 152  * Locking: must be called within a read rcu section.
 153  */
 154 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 155 {
 156         struct mesh_path *mpath;
 157         struct hlist_node *n;
 158         struct hlist_head *bucket;
 159         struct mesh_table *tbl;
 160         struct mpath_node *node;
 161
 162         tbl = rcu_dereference(mesh_paths);
 163
 164         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 165         hlist_for_each_entry_rcu(node, n, bucket, list) {
 166                 mpath = node->mpath;
 167                 if (mpath->sdata == sdata &&
 168                                 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 169                         if (MPATH_EXPIRED(mpath)) {
 170                                 spin_lock_bh(&mpath->state_lock);
 171                                 if (MPATH_EXPIRED(mpath))
 172                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 173                                 spin_unlock_bh(&mpath->state_lock);
 174                         }
 175                         return mpath;
 176                 }
 177         }
 178         return NULL;
 179 }
 180
 181 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 182 {
 183         struct mesh_path *mpath;
 184         struct hlist_node *n;
 185         struct hlist_head *bucket;
 186         struct mesh_table *tbl;
 187         struct mpath_node *node;
 188
 189         tbl = rcu_dereference(mpp_paths);
 190
 191         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 192         hlist_for_each_entry_rcu(node, n, bucket, list) {
 193                 mpath = node->mpath;
 194                 if (mpath->sdata == sdata &&
 195                     memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 196                         if (MPATH_EXPIRED(mpath)) {
 197                                 spin_lock_bh(&mpath->state_lock);
 198                                 if (MPATH_EXPIRED(mpath))
 199                                         mpath->flags &= ~MESH_PATH_ACTIVE;
 200                                 spin_unlock_bh(&mpath->state_lock);
 201                         }
 202                         return mpath;
 203                 }
 204         }
 205         return NULL;
 206 }
 207
 208
 209 /**
 210  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 211  * @idx: index
 212  * @sdata: local subif, or NULL for all entries
 213  *
 214  * Returns: pointer to the mesh path structure, or NULL if not found.
 215  *
 216  * Locking: must be called within a read rcu section.
 217  */
 218 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 219 {
 220         struct mpath_node *node;
 221         struct hlist_node *p;
 222         int i;
 223         int j = 0;
 224
 225         for_each_mesh_entry(mesh_paths, p, node, i) {
 226                 if (sdata && node->mpath->sdata != sdata)
 227                         continue;
 228                 if (j++ == idx) {
 229                         if (MPATH_EXPIRED(node->mpath)) {
 230                                 spin_lock_bh(&node->mpath->state_lock);
 231                                 if (MPATH_EXPIRED(node->mpath))
 232                                         node->mpath->flags &= ~MESH_PATH_ACTIVE;
 233                                 spin_unlock_bh(&node->mpath->state_lock);
 234                         }
 235                         return node->mpath;
 236                 }
 237         }
 238
 239         return NULL;
 240 }
 241
 242 /**
 243  * mesh_path_add - allocate and add a new path to the mesh path table
 244  * @addr: destination address of the path (ETH_ALEN length)
 245  * @sdata: local subif
 246  *
 247  * Returns: 0 on sucess
 248  *
 249  * State: the initial state of the new path is set to 0
 250  */
 251 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 252 {
 253         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 254         struct ieee80211_local *local = sdata->local;
 255         struct mesh_path *mpath, *new_mpath;
 256         struct mpath_node *node, *new_node;
 257         struct hlist_head *bucket;
 258         struct hlist_node *n;
 259         int grow = 0;
 260         int err = 0;
 261         u32 hash_idx;
 262
 263         if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
 264                 /* never add ourselves as neighbours */
 265                 return -ENOTSUPP;
 266
 267         if (is_multicast_ether_addr(dst))
 268                 return -ENOTSUPP;
 269
 270         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 271                 return -ENOSPC;
 272
 273         err = -ENOMEM;
 274         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 275         if (!new_mpath)
 276                 goto err_path_alloc;
 277
 278         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 279         if (!new_node)
 280                 goto err_node_alloc;
 281
 282         read_lock(&pathtbl_resize_lock);
 283         memcpy(new_mpath->dst, dst, ETH_ALEN);
 284         new_mpath->sdata = sdata;
 285         new_mpath->flags = 0;
 286         skb_queue_head_init(&new_mpath->frame_queue);
 287         new_node->mpath = new_mpath;
 288         new_mpath->timer.data = (unsigned long) new_mpath;
 289         new_mpath->timer.function = mesh_path_timer;
 290         new_mpath->exp_time = jiffies;
 291         spin_lock_init(&new_mpath->state_lock);
 292         init_timer(&new_mpath->timer);
 293
 294         hash_idx = mesh_table_hash(dst, sdata, mesh_paths);
 295         bucket = &mesh_paths->hash_buckets[hash_idx];
 296
 297         spin_lock(&mesh_paths->hashwlock[hash_idx]);
 298
 299         err = -EEXIST;
 300         hlist_for_each_entry(node, n, bucket, list) {
 301                 mpath = node->mpath;
 302                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 303                         goto err_exists;
 304         }
 305
 306         hlist_add_head_rcu(&new_node->list, bucket);
 307         if (atomic_inc_return(&mesh_paths->entries) >=
 308                 mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
 309                 grow = 1;
 310
 311         mesh_paths_generation++;
 312
 313         spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 314         read_unlock(&pathtbl_resize_lock);
 315         if (grow) {
 316                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 317                 ieee80211_queue_work(&local->hw, &ifmsh->work);
 318         }
 319         return 0;
 320
 321 err_exists:
 322         spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 323         read_unlock(&pathtbl_resize_lock);
 324         kfree(new_node);
 325 err_node_alloc:
 326         kfree(new_mpath);
 327 err_path_alloc:
 328         atomic_dec(&sdata->u.mesh.mpaths);
 329         return err;
 330 }
 331
 332 void mesh_mpath_table_grow(void)
 333 {
 334         struct mesh_table *oldtbl, *newtbl;
 335
 336         write_lock(&pathtbl_resize_lock);
 337         oldtbl = mesh_paths;
 338         newtbl = mesh_table_grow(mesh_paths);
 339         if (!newtbl) {
 340                 write_unlock(&pathtbl_resize_lock);
 341                 return;
 342         }
 343         rcu_assign_pointer(mesh_paths, newtbl);
 344         write_unlock(&pathtbl_resize_lock);
 345
 346         synchronize_rcu();
 347         mesh_table_free(oldtbl, false);
 348 }
 349
 350 void mesh_mpp_table_grow(void)
 351 {
 352         struct mesh_table *oldtbl, *newtbl;
 353
 354         write_lock(&pathtbl_resize_lock);
 355         oldtbl = mpp_paths;
 356         newtbl = mesh_table_grow(mpp_paths);
 357         if (!newtbl) {
 358                 write_unlock(&pathtbl_resize_lock);
 359                 return;
 360         }
 361         rcu_assign_pointer(mpp_paths, newtbl);
 362         write_unlock(&pathtbl_resize_lock);
 363
 364         synchronize_rcu();
 365         mesh_table_free(oldtbl, false);
 366 }
 367
 368 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 369 {
 370         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 371         struct ieee80211_local *local = sdata->local;
 372         struct mesh_path *mpath, *new_mpath;
 373         struct mpath_node *node, *new_node;
 374         struct hlist_head *bucket;
 375         struct hlist_node *n;
 376         int grow = 0;
 377         int err = 0;
 378         u32 hash_idx;
 379
 380         if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
 381                 /* never add ourselves as neighbours */
 382                 return -ENOTSUPP;
 383
 384         if (is_multicast_ether_addr(dst))
 385                 return -ENOTSUPP;
 386
 387         err = -ENOMEM;
 388         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 389         if (!new_mpath)
 390                 goto err_path_alloc;
 391
 392         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 393         if (!new_node)
 394                 goto err_node_alloc;
 395
 396         read_lock(&pathtbl_resize_lock);
 397         memcpy(new_mpath->dst, dst, ETH_ALEN);
 398         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 399         new_mpath->sdata = sdata;
 400         new_mpath->flags = 0;
 401         skb_queue_head_init(&new_mpath->frame_queue);
 402         new_node->mpath = new_mpath;
 403         new_mpath->exp_time = jiffies;
 404         spin_lock_init(&new_mpath->state_lock);
 405
 406         hash_idx = mesh_table_hash(dst, sdata, mpp_paths);
 407         bucket = &mpp_paths->hash_buckets[hash_idx];
 408
 409         spin_lock(&mpp_paths->hashwlock[hash_idx]);
 410
 411         err = -EEXIST;
 412         hlist_for_each_entry(node, n, bucket, list) {
 413                 mpath = node->mpath;
 414                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 415                         goto err_exists;
 416         }
 417
 418         hlist_add_head_rcu(&new_node->list, bucket);
 419         if (atomic_inc_return(&mpp_paths->entries) >=
 420                 mpp_paths->mean_chain_len * (mpp_paths->hash_mask + 1))
 421                 grow = 1;
 422
 423         spin_unlock(&mpp_paths->hashwlock[hash_idx]);
 424         read_unlock(&pathtbl_resize_lock);
 425         if (grow) {
 426                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 427                 ieee80211_queue_work(&local->hw, &ifmsh->work);
 428         }
 429         return 0;
 430
 431 err_exists:
 432         spin_unlock(&mpp_paths->hashwlock[hash_idx]);
 433         read_unlock(&pathtbl_resize_lock);
 434         kfree(new_node);
 435 err_node_alloc:
 436         kfree(new_mpath);
 437 err_path_alloc:
 438         return err;
 439 }
 440
 441
 442 /**
 443  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 444  *
 445  * @sta: broken peer link
 446  *
 447  * This function must be called from the rate control algorithm if enough
 448  * delivery errors suggest that a peer link is no longer usable.
 449  */
 450 void mesh_plink_broken(struct sta_info *sta)
 451 {
 452         struct mesh_path *mpath;
 453         struct mpath_node *node;
 454         struct hlist_node *p;
 455         struct ieee80211_sub_if_data *sdata = sta->sdata;
 456         int i;
 457
 458         rcu_read_lock();
 459         for_each_mesh_entry(mesh_paths, p, node, i) {
 460                 mpath = node->mpath;
 461                 spin_lock_bh(&mpath->state_lock);
 462                 if (mpath->next_hop == sta &&
 463                     mpath->flags & MESH_PATH_ACTIVE &&
 464                     !(mpath->flags & MESH_PATH_FIXED)) {
 465                         mpath->flags &= ~MESH_PATH_ACTIVE;
 466                         ++mpath->dsn;
 467                         spin_unlock_bh(&mpath->state_lock);
 468                         mesh_path_error_tx(mpath->dst,
 469                                         cpu_to_le32(mpath->dsn),
 470                                         sdata->dev->broadcast, sdata);
 471                 } else
 472                 spin_unlock_bh(&mpath->state_lock);
 473         }
 474         rcu_read_unlock();
 475 }
 476
 477 /**
 478  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 479  *
 480  * @sta - mesh peer to match
 481  *
 482  * RCU notes: this function is called when a mesh plink transitions from
 483  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 484  * allows path creation. This will happen before the sta can be freed (because
 485  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 486  * protected against the plink disappearing.
 487  */
 488 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 489 {
 490         struct mesh_path *mpath;
 491         struct mpath_node *node;
 492         struct hlist_node *p;
 493         int i;
 494
 495         for_each_mesh_entry(mesh_paths, p, node, i) {
 496                 mpath = node->mpath;
 497                 if (mpath->next_hop == sta)
 498                         mesh_path_del(mpath->dst, mpath->sdata);
 499         }
 500 }
 501
 502 void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
 503 {
 504         struct mesh_path *mpath;
 505         struct mpath_node *node;
 506         struct hlist_node *p;
 507         int i;
 508
 509         for_each_mesh_entry(mesh_paths, p, node, i) {
 510                 mpath = node->mpath;
 511                 if (mpath->sdata == sdata)
 512                         mesh_path_del(mpath->dst, mpath->sdata);
 513         }
 514 }
 515
 516 static void mesh_path_node_reclaim(struct rcu_head *rp)
 517 {
 518         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 519         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 520
 521         del_timer_sync(&node->mpath->timer);
 522         atomic_dec(&sdata->u.mesh.mpaths);
 523         kfree(node->mpath);
 524         kfree(node);
 525 }
 526
 527 /**
 528  * mesh_path_del - delete a mesh path from the table
 529  *
 530  * @addr: dst address (ETH_ALEN length)
 531  * @sdata: local subif
 532  *
 533  * Returns: 0 if succesful
 534  */
 535 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 536 {
 537         struct mesh_path *mpath;
 538         struct mpath_node *node;
 539         struct hlist_head *bucket;
 540         struct hlist_node *n;
 541         int hash_idx;
 542         int err = 0;
 543
 544         read_lock(&pathtbl_resize_lock);
 545         hash_idx = mesh_table_hash(addr, sdata, mesh_paths);
 546         bucket = &mesh_paths->hash_buckets[hash_idx];
 547
 548         spin_lock(&mesh_paths->hashwlock[hash_idx]);
 549         hlist_for_each_entry(node, n, bucket, list) {
 550                 mpath = node->mpath;
 551                 if (mpath->sdata == sdata &&
 552                                 memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
 553                         spin_lock_bh(&mpath->state_lock);
 554                         mpath->flags |= MESH_PATH_RESOLVING;
 555                         hlist_del_rcu(&node->list);
 556                         call_rcu(&node->rcu, mesh_path_node_reclaim);
 557                         atomic_dec(&mesh_paths->entries);
 558                         spin_unlock_bh(&mpath->state_lock);
 559                         goto enddel;
 560                 }
 561         }
 562
 563         err = -ENXIO;
 564 enddel:
 565         mesh_paths_generation++;
 566         spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 567         read_unlock(&pathtbl_resize_lock);
 568         return err;
 569 }
 570
 571 /**
 572  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 573  *
 574  * @mpath: mesh path to activate
 575  *
 576  * Locking: the state_lock of the mpath structure must NOT be held when calling
 577  * this function.
 578  */
 579 void mesh_path_tx_pending(struct mesh_path *mpath)
 580 {
 581         if (mpath->flags & MESH_PATH_ACTIVE)
 582                 ieee80211_add_pending_skbs(mpath->sdata->local,
 583                                 &mpath->frame_queue);
 584 }
 585
 586 /**
 587  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 588  *
 589  * @skb: frame to discard
 590  * @sdata: network subif the frame was to be sent through
 591  *
 592  * If the frame was being forwarded from another MP, a PERR frame will be sent
 593  * to the precursor.  The precursor's address (i.e. the previous hop) was saved
 594  * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
 595  * the destination is successfully resolved.
 596  *
 597  * Locking: the function must me called within a rcu_read_lock region
 598  */
 599 void mesh_path_discard_frame(struct sk_buff *skb,
 600                              struct ieee80211_sub_if_data *sdata)
 601 {
 602         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 603         struct mesh_path *mpath;
 604         u32 dsn = 0;
 605
 606         if (memcmp(hdr->addr4, sdata->dev->dev_addr, ETH_ALEN) != 0) {
 607                 u8 *ra, *da;
 608
 609                 da = hdr->addr3;
 610                 ra = hdr->addr1;
 611                 mpath = mesh_path_lookup(da, sdata);
 612                 if (mpath)
 613                         dsn = ++mpath->dsn;
 614                 mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, sdata);
 615         }
 616
 617         kfree_skb(skb);
 618         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 619 }
 620
 621 /**
 622  * mesh_path_flush_pending - free the pending queue of a mesh path
 623  *
 624  * @mpath: mesh path whose queue has to be freed
 625  *
 626  * Locking: the function must me called withing a rcu_read_lock region
 627  */
 628 void mesh_path_flush_pending(struct mesh_path *mpath)
 629 {
 630         struct sk_buff *skb;
 631
 632         while ((skb = skb_dequeue(&mpath->frame_queue)) &&
 633                         (mpath->flags & MESH_PATH_ACTIVE))
 634                 mesh_path_discard_frame(skb, mpath->sdata);
 635 }
 636
 637 /**
 638  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 639  *
 640  * @mpath: the mesh path to modify
 641  * @next_hop: the next hop to force
 642  *
 643  * Locking: this function must be called holding mpath->state_lock
 644  */
 645 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 646 {
 647         spin_lock_bh(&mpath->state_lock);
 648         mesh_path_assign_nexthop(mpath, next_hop);
 649         mpath->dsn = 0xffff;
 650         mpath->metric = 0;
 651         mpath->hop_count = 0;
 652         mpath->exp_time = 0;
 653         mpath->flags |= MESH_PATH_FIXED;
 654         mesh_path_activate(mpath);
 655         spin_unlock_bh(&mpath->state_lock);
 656         mesh_path_tx_pending(mpath);
 657 }
 658
 659 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
 660 {
 661         struct mesh_path *mpath;
 662         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
 663         mpath = node->mpath;
 664         hlist_del_rcu(p);
 665         if (free_leafs)
 666                 kfree(mpath);
 667         kfree(node);
 668 }
 669
 670 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
 671 {
 672         struct mesh_path *mpath;
 673         struct mpath_node *node, *new_node;
 674         u32 hash_idx;
 675
 676         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 677         if (new_node == NULL)
 678                 return -ENOMEM;
 679
 680         node = hlist_entry(p, struct mpath_node, list);
 681         mpath = node->mpath;
 682         new_node->mpath = mpath;
 683         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
 684         hlist_add_head(&new_node->list,
 685                         &newtbl->hash_buckets[hash_idx]);
 686         return 0;
 687 }
 688
 689 int mesh_pathtbl_init(void)
 690 {
 691         mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 692         if (!mesh_paths)
 693                 return -ENOMEM;
 694         mesh_paths->free_node = &mesh_path_node_free;
 695         mesh_paths->copy_node = &mesh_path_node_copy;
 696         mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
 697
 698         mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 699         if (!mpp_paths) {
 700                 mesh_table_free(mesh_paths, true);
 701                 return -ENOMEM;
 702         }
 703         mpp_paths->free_node = &mesh_path_node_free;
 704         mpp_paths->copy_node = &mesh_path_node_copy;
 705         mpp_paths->mean_chain_len = MEAN_CHAIN_LEN;
 706
 707         return 0;
 708 }
 709
 710 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 711 {
 712         struct mesh_path *mpath;
 713         struct mpath_node *node;
 714         struct hlist_node *p;
 715         int i;
 716
 717         read_lock(&pathtbl_resize_lock);
 718         for_each_mesh_entry(mesh_paths, p, node, i) {
 719                 if (node->mpath->sdata != sdata)
 720                         continue;
 721                 mpath = node->mpath;
 722                 spin_lock_bh(&mpath->state_lock);
 723                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 724                     (!(mpath->flags & MESH_PATH_FIXED)) &&
 725                         time_after(jiffies,
 726                          mpath->exp_time + MESH_PATH_EXPIRE)) {
 727                         spin_unlock_bh(&mpath->state_lock);
 728                         mesh_path_del(mpath->dst, mpath->sdata);
 729                 } else
 730                         spin_unlock_bh(&mpath->state_lock);
 731         }
 732         read_unlock(&pathtbl_resize_lock);
 733 }
 734
 735 void mesh_pathtbl_unregister(void)
 736 {
 737         mesh_table_free(mesh_paths, true);
 738         mesh_table_free(mpp_paths, true);
 739 }