Pileus Git - ~andy/linux/blob - net/mac80211/mesh_pathtbl.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/etherdevice.h>
  11 #include <linux/list.h>
  12 #include <linux/random.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/string.h>
  16 #include <net/mac80211.h>
  17 #include "wme.h"
  18 #include "ieee80211_i.h"
  19 #include "mesh.h"
  20
  21 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  22 #define INIT_PATHS_SIZE_ORDER   2
  23
  24 /* Keep the mean chain length below this constant */
  25 #define MEAN_CHAIN_LEN          2
  26
  27 static inline bool mpath_expired(struct mesh_path *mpath)
  28 {
  29         return (mpath->flags & MESH_PATH_ACTIVE) &&
  30                time_after(jiffies, mpath->exp_time) &&
  31                !(mpath->flags & MESH_PATH_FIXED);
  32 }
  33
  34 struct mpath_node {
  35         struct hlist_node list;
  36         struct rcu_head rcu;
  37         /* This indirection allows two different tables to point to the same
  38          * mesh_path structure, useful when resizing
  39          */
  40         struct mesh_path *mpath;
  41 };
  42
  43 static struct mesh_table __rcu *mesh_paths;
  44 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  45
  46 int mesh_paths_generation;
  47
  48 /* This lock will have the grow table function as writer and add / delete nodes
  49  * as readers. RCU provides sufficient protection only when reading the table
  50  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  51  * the read lock or we risk operating on an old table.  The write lock is only
  52  * needed when modifying the number of buckets a table.
  53  */
  54 static DEFINE_RWLOCK(pathtbl_resize_lock);
  55
  56
  57 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  58 {
  59         return rcu_dereference_protected(mesh_paths,
  60                 lockdep_is_held(&pathtbl_resize_lock));
  61 }
  62
  63 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  64 {
  65         return rcu_dereference_protected(mpp_paths,
  66                 lockdep_is_held(&pathtbl_resize_lock));
  67 }
  68
  69 /*
  70  * CAREFUL -- "tbl" must not be an expression,
  71  * in particular not an rcu_dereference(), since
  72  * it's used twice. So it is illegal to do
  73  *      for_each_mesh_entry(rcu_dereference(...), ...)
  74  */
  75 #define for_each_mesh_entry(tbl, 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         spin_lock_init(&newtbl->gates_lock);
 113
 114         return newtbl;
 115 }
 116
 117 static void __mesh_table_free(struct mesh_table *tbl)
 118 {
 119         kfree(tbl->hash_buckets);
 120         kfree(tbl->hashwlock);
 121         kfree(tbl);
 122 }
 123
 124 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 125 {
 126         struct hlist_head *mesh_hash;
 127         struct hlist_node *p, *q;
 128         struct mpath_node *gate;
 129         int i;
 130
 131         mesh_hash = tbl->hash_buckets;
 132         for (i = 0; i <= tbl->hash_mask; i++) {
 133                 spin_lock_bh(&tbl->hashwlock[i]);
 134                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 135                         tbl->free_node(p, free_leafs);
 136                         atomic_dec(&tbl->entries);
 137                 }
 138                 spin_unlock_bh(&tbl->hashwlock[i]);
 139         }
 140         if (free_leafs) {
 141                 spin_lock_bh(&tbl->gates_lock);
 142                 hlist_for_each_entry_safe(gate, p, q,
 143                                          tbl->known_gates, list) {
 144                         hlist_del(&gate->list);
 145                         kfree(gate);
 146                 }
 147                 kfree(tbl->known_gates);
 148                 spin_unlock_bh(&tbl->gates_lock);
 149         }
 150
 151         __mesh_table_free(tbl);
 152 }
 153
 154 static int mesh_table_grow(struct mesh_table *oldtbl,
 155                            struct mesh_table *newtbl)
 156 {
 157         struct hlist_head *oldhash;
 158         struct hlist_node *p, *q;
 159         int i;
 160
 161         if (atomic_read(&oldtbl->entries)
 162                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 163                 return -EAGAIN;
 164
 165         newtbl->free_node = oldtbl->free_node;
 166         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 167         newtbl->copy_node = oldtbl->copy_node;
 168         newtbl->known_gates = oldtbl->known_gates;
 169         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 170
 171         oldhash = oldtbl->hash_buckets;
 172         for (i = 0; i <= oldtbl->hash_mask; i++)
 173                 hlist_for_each(p, &oldhash[i])
 174                         if (oldtbl->copy_node(p, newtbl) < 0)
 175                                 goto errcopy;
 176
 177         return 0;
 178
 179 errcopy:
 180         for (i = 0; i <= newtbl->hash_mask; i++) {
 181                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 182                         oldtbl->free_node(p, 0);
 183         }
 184         return -ENOMEM;
 185 }
 186
 187 static u32 mesh_table_hash(const u8 *addr, struct ieee80211_sub_if_data *sdata,
 188                            struct mesh_table *tbl)
 189 {
 190         /* Use last four bytes of hw addr and interface index as hash index */
 191         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex,
 192                             tbl->hash_rnd) & tbl->hash_mask;
 193 }
 194
 195
 196 /**
 197  *
 198  * mesh_path_assign_nexthop - update mesh path next hop
 199  *
 200  * @mpath: mesh path to update
 201  * @sta: next hop to assign
 202  *
 203  * Locking: mpath->state_lock must be held when calling this function
 204  */
 205 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 206 {
 207         struct sk_buff *skb;
 208         struct ieee80211_hdr *hdr;
 209         unsigned long flags;
 210
 211         rcu_assign_pointer(mpath->next_hop, sta);
 212
 213         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 214         skb_queue_walk(&mpath->frame_queue, skb) {
 215                 hdr = (struct ieee80211_hdr *) skb->data;
 216                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 217                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 218                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 219         }
 220
 221         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 222 }
 223
 224 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 225                              struct mesh_path *gate_mpath)
 226 {
 227         struct ieee80211_hdr *hdr;
 228         struct ieee80211s_hdr *mshdr;
 229         int mesh_hdrlen, hdrlen;
 230         char *next_hop;
 231
 232         hdr = (struct ieee80211_hdr *) skb->data;
 233         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 234         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 235
 236         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 237                 /* size of the fixed part of the mesh header */
 238                 mesh_hdrlen = 6;
 239
 240                 /* make room for the two extended addresses */
 241                 skb_push(skb, 2 * ETH_ALEN);
 242                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 243
 244                 hdr = (struct ieee80211_hdr *) skb->data;
 245
 246                 /* we preserve the previous mesh header and only add
 247                  * the new addreses */
 248                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 249                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 250                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 251                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 252         }
 253
 254         /* update next hop */
 255         hdr = (struct ieee80211_hdr *) skb->data;
 256         rcu_read_lock();
 257         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 258         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 259         rcu_read_unlock();
 260         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 261         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 262 }
 263
 264 /**
 265  *
 266  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 267  *
 268  * This function is used to transfer or copy frames from an unresolved mpath to
 269  * a gate mpath.  The function also adds the Address Extension field and
 270  * updates the next hop.
 271  *
 272  * If a frame already has an Address Extension field, only the next hop and
 273  * destination addresses are updated.
 274  *
 275  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 276  *
 277  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 278  * @from_mpath: The failed mpath
 279  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 280  * move them.
 281  */
 282 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 283                                     struct mesh_path *from_mpath,
 284                                     bool copy)
 285 {
 286         struct sk_buff *skb, *fskb, *tmp;
 287         struct sk_buff_head failq;
 288         unsigned long flags;
 289
 290         BUG_ON(gate_mpath == from_mpath);
 291         BUG_ON(!gate_mpath->next_hop);
 292
 293         __skb_queue_head_init(&failq);
 294
 295         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 296         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 297         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 298
 299         skb_queue_walk_safe(&failq, fskb, tmp) {
 300                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 301                                   MESH_FRAME_QUEUE_LEN) {
 302                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 303                         break;
 304                 }
 305
 306                 skb = skb_copy(fskb, GFP_ATOMIC);
 307                 if (WARN_ON(!skb))
 308                         break;
 309
 310                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 311                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 312
 313                 if (copy)
 314                         continue;
 315
 316                 __skb_unlink(fskb, &failq);
 317                 kfree_skb(fskb);
 318         }
 319
 320         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 321                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 322
 323         if (!copy)
 324                 return;
 325
 326         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 327         skb_queue_splice(&failq, &from_mpath->frame_queue);
 328         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 329 }
 330
 331
 332 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 333                                       struct ieee80211_sub_if_data *sdata)
 334 {
 335         struct mesh_path *mpath;
 336         struct hlist_node *n;
 337         struct hlist_head *bucket;
 338         struct mpath_node *node;
 339
 340         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 341         hlist_for_each_entry_rcu(node, n, bucket, list) {
 342                 mpath = node->mpath;
 343                 if (mpath->sdata == sdata &&
 344                     ether_addr_equal(dst, mpath->dst)) {
 345                         if (mpath_expired(mpath)) {
 346                                 spin_lock_bh(&mpath->state_lock);
 347                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 348                                 spin_unlock_bh(&mpath->state_lock);
 349                         }
 350                         return mpath;
 351                 }
 352         }
 353         return NULL;
 354 }
 355
 356 /**
 357  * mesh_path_lookup - look up a path in the mesh path table
 358  * @sdata: local subif
 359  * @dst: hardware address (ETH_ALEN length) of destination
 360  *
 361  * Returns: pointer to the mesh path structure, or NULL if not found
 362  *
 363  * Locking: must be called within a read rcu section.
 364  */
 365 struct mesh_path *
 366 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 367 {
 368         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 369 }
 370
 371 struct mesh_path *
 372 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 373 {
 374         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 375 }
 376
 377
 378 /**
 379  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 380  * @idx: index
 381  * @sdata: local subif, or NULL for all entries
 382  *
 383  * Returns: pointer to the mesh path structure, or NULL if not found.
 384  *
 385  * Locking: must be called within a read rcu section.
 386  */
 387 struct mesh_path *
 388 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 389 {
 390         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 391         struct mpath_node *node;
 392         struct hlist_node *p;
 393         int i;
 394         int j = 0;
 395
 396         for_each_mesh_entry(tbl, p, node, i) {
 397                 if (sdata && node->mpath->sdata != sdata)
 398                         continue;
 399                 if (j++ == idx) {
 400                         if (mpath_expired(node->mpath)) {
 401                                 spin_lock_bh(&node->mpath->state_lock);
 402                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 403                                 spin_unlock_bh(&node->mpath->state_lock);
 404                         }
 405                         return node->mpath;
 406                 }
 407         }
 408
 409         return NULL;
 410 }
 411
 412 /**
 413  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 414  * @mpath: gate path to add to table
 415  */
 416 int mesh_path_add_gate(struct mesh_path *mpath)
 417 {
 418         struct mesh_table *tbl;
 419         struct mpath_node *gate, *new_gate;
 420         struct hlist_node *n;
 421         int err;
 422
 423         rcu_read_lock();
 424         tbl = rcu_dereference(mesh_paths);
 425
 426         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
 427                 if (gate->mpath == mpath) {
 428                         err = -EEXIST;
 429                         goto err_rcu;
 430                 }
 431
 432         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 433         if (!new_gate) {
 434                 err = -ENOMEM;
 435                 goto err_rcu;
 436         }
 437
 438         mpath->is_gate = true;
 439         mpath->sdata->u.mesh.num_gates++;
 440         new_gate->mpath = mpath;
 441         spin_lock_bh(&tbl->gates_lock);
 442         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 443         spin_unlock_bh(&tbl->gates_lock);
 444         mpath_dbg(mpath->sdata,
 445                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 446                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 447         err = 0;
 448 err_rcu:
 449         rcu_read_unlock();
 450         return err;
 451 }
 452
 453 /**
 454  * mesh_gate_del - remove a mesh gate from the list of known gates
 455  * @tbl: table which holds our list of known gates
 456  * @mpath: gate mpath
 457  *
 458  * Locking: must be called inside rcu_read_lock() section
 459  */
 460 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 461 {
 462         struct mpath_node *gate;
 463         struct hlist_node *p, *q;
 464
 465         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list) {
 466                 if (gate->mpath != mpath)
 467                         continue;
 468                 spin_lock_bh(&tbl->gates_lock);
 469                 hlist_del_rcu(&gate->list);
 470                 kfree_rcu(gate, rcu);
 471                 spin_unlock_bh(&tbl->gates_lock);
 472                 mpath->sdata->u.mesh.num_gates--;
 473                 mpath->is_gate = false;
 474                 mpath_dbg(mpath->sdata,
 475                           "Mesh path: Deleted gate: %pM. %d known gates\n",
 476                           mpath->dst, mpath->sdata->u.mesh.num_gates);
 477                 break;
 478         }
 479 }
 480
 481 /**
 482  * mesh_gate_num - number of gates known to this interface
 483  * @sdata: subif data
 484  */
 485 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 486 {
 487         return sdata->u.mesh.num_gates;
 488 }
 489
 490 /**
 491  * mesh_path_add - allocate and add a new path to the mesh path table
 492  * @dst: destination address of the path (ETH_ALEN length)
 493  * @sdata: local subif
 494  *
 495  * Returns: 0 on success
 496  *
 497  * State: the initial state of the new path is set to 0
 498  */
 499 int mesh_path_add(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 500 {
 501         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 502         struct ieee80211_local *local = sdata->local;
 503         struct mesh_table *tbl;
 504         struct mesh_path *mpath, *new_mpath;
 505         struct mpath_node *node, *new_node;
 506         struct hlist_head *bucket;
 507         struct hlist_node *n;
 508         int grow = 0;
 509         int err = 0;
 510         u32 hash_idx;
 511
 512         if (ether_addr_equal(dst, sdata->vif.addr))
 513                 /* never add ourselves as neighbours */
 514                 return -ENOTSUPP;
 515
 516         if (is_multicast_ether_addr(dst))
 517                 return -ENOTSUPP;
 518
 519         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 520                 return -ENOSPC;
 521
 522         err = -ENOMEM;
 523         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 524         if (!new_mpath)
 525                 goto err_path_alloc;
 526
 527         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 528         if (!new_node)
 529                 goto err_node_alloc;
 530
 531         read_lock_bh(&pathtbl_resize_lock);
 532         memcpy(new_mpath->dst, dst, ETH_ALEN);
 533         eth_broadcast_addr(new_mpath->rann_snd_addr);
 534         new_mpath->is_root = false;
 535         new_mpath->sdata = sdata;
 536         new_mpath->flags = 0;
 537         skb_queue_head_init(&new_mpath->frame_queue);
 538         new_node->mpath = new_mpath;
 539         new_mpath->timer.data = (unsigned long) new_mpath;
 540         new_mpath->timer.function = mesh_path_timer;
 541         new_mpath->exp_time = jiffies;
 542         spin_lock_init(&new_mpath->state_lock);
 543         init_timer(&new_mpath->timer);
 544
 545         tbl = resize_dereference_mesh_paths();
 546
 547         hash_idx = mesh_table_hash(dst, sdata, tbl);
 548         bucket = &tbl->hash_buckets[hash_idx];
 549
 550         spin_lock(&tbl->hashwlock[hash_idx]);
 551
 552         err = -EEXIST;
 553         hlist_for_each_entry(node, n, bucket, list) {
 554                 mpath = node->mpath;
 555                 if (mpath->sdata == sdata &&
 556                     ether_addr_equal(dst, mpath->dst))
 557                         goto err_exists;
 558         }
 559
 560         hlist_add_head_rcu(&new_node->list, bucket);
 561         if (atomic_inc_return(&tbl->entries) >=
 562             tbl->mean_chain_len * (tbl->hash_mask + 1))
 563                 grow = 1;
 564
 565         mesh_paths_generation++;
 566
 567         spin_unlock(&tbl->hashwlock[hash_idx]);
 568         read_unlock_bh(&pathtbl_resize_lock);
 569         if (grow) {
 570                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 571                 ieee80211_queue_work(&local->hw, &sdata->work);
 572         }
 573         return 0;
 574
 575 err_exists:
 576         spin_unlock(&tbl->hashwlock[hash_idx]);
 577         read_unlock_bh(&pathtbl_resize_lock);
 578         kfree(new_node);
 579 err_node_alloc:
 580         kfree(new_mpath);
 581 err_path_alloc:
 582         atomic_dec(&sdata->u.mesh.mpaths);
 583         return err;
 584 }
 585
 586 static void mesh_table_free_rcu(struct rcu_head *rcu)
 587 {
 588         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 589
 590         mesh_table_free(tbl, false);
 591 }
 592
 593 void mesh_mpath_table_grow(void)
 594 {
 595         struct mesh_table *oldtbl, *newtbl;
 596
 597         write_lock_bh(&pathtbl_resize_lock);
 598         oldtbl = resize_dereference_mesh_paths();
 599         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 600         if (!newtbl)
 601                 goto out;
 602         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 603                 __mesh_table_free(newtbl);
 604                 goto out;
 605         }
 606         rcu_assign_pointer(mesh_paths, newtbl);
 607
 608         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 609
 610  out:
 611         write_unlock_bh(&pathtbl_resize_lock);
 612 }
 613
 614 void mesh_mpp_table_grow(void)
 615 {
 616         struct mesh_table *oldtbl, *newtbl;
 617
 618         write_lock_bh(&pathtbl_resize_lock);
 619         oldtbl = resize_dereference_mpp_paths();
 620         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 621         if (!newtbl)
 622                 goto out;
 623         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 624                 __mesh_table_free(newtbl);
 625                 goto out;
 626         }
 627         rcu_assign_pointer(mpp_paths, newtbl);
 628         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 629
 630  out:
 631         write_unlock_bh(&pathtbl_resize_lock);
 632 }
 633
 634 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 635                  const u8 *dst, const u8 *mpp)
 636 {
 637         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 638         struct ieee80211_local *local = sdata->local;
 639         struct mesh_table *tbl;
 640         struct mesh_path *mpath, *new_mpath;
 641         struct mpath_node *node, *new_node;
 642         struct hlist_head *bucket;
 643         struct hlist_node *n;
 644         int grow = 0;
 645         int err = 0;
 646         u32 hash_idx;
 647
 648         if (ether_addr_equal(dst, sdata->vif.addr))
 649                 /* never add ourselves as neighbours */
 650                 return -ENOTSUPP;
 651
 652         if (is_multicast_ether_addr(dst))
 653                 return -ENOTSUPP;
 654
 655         err = -ENOMEM;
 656         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 657         if (!new_mpath)
 658                 goto err_path_alloc;
 659
 660         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 661         if (!new_node)
 662                 goto err_node_alloc;
 663
 664         read_lock_bh(&pathtbl_resize_lock);
 665         memcpy(new_mpath->dst, dst, ETH_ALEN);
 666         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 667         new_mpath->sdata = sdata;
 668         new_mpath->flags = 0;
 669         skb_queue_head_init(&new_mpath->frame_queue);
 670         new_node->mpath = new_mpath;
 671         init_timer(&new_mpath->timer);
 672         new_mpath->exp_time = jiffies;
 673         spin_lock_init(&new_mpath->state_lock);
 674
 675         tbl = resize_dereference_mpp_paths();
 676
 677         hash_idx = mesh_table_hash(dst, sdata, tbl);
 678         bucket = &tbl->hash_buckets[hash_idx];
 679
 680         spin_lock(&tbl->hashwlock[hash_idx]);
 681
 682         err = -EEXIST;
 683         hlist_for_each_entry(node, n, bucket, list) {
 684                 mpath = node->mpath;
 685                 if (mpath->sdata == sdata &&
 686                     ether_addr_equal(dst, mpath->dst))
 687                         goto err_exists;
 688         }
 689
 690         hlist_add_head_rcu(&new_node->list, bucket);
 691         if (atomic_inc_return(&tbl->entries) >=
 692             tbl->mean_chain_len * (tbl->hash_mask + 1))
 693                 grow = 1;
 694
 695         spin_unlock(&tbl->hashwlock[hash_idx]);
 696         read_unlock_bh(&pathtbl_resize_lock);
 697         if (grow) {
 698                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 699                 ieee80211_queue_work(&local->hw, &sdata->work);
 700         }
 701         return 0;
 702
 703 err_exists:
 704         spin_unlock(&tbl->hashwlock[hash_idx]);
 705         read_unlock_bh(&pathtbl_resize_lock);
 706         kfree(new_node);
 707 err_node_alloc:
 708         kfree(new_mpath);
 709 err_path_alloc:
 710         return err;
 711 }
 712
 713
 714 /**
 715  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 716  *
 717  * @sta: broken peer link
 718  *
 719  * This function must be called from the rate control algorithm if enough
 720  * delivery errors suggest that a peer link is no longer usable.
 721  */
 722 void mesh_plink_broken(struct sta_info *sta)
 723 {
 724         struct mesh_table *tbl;
 725         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 726         struct mesh_path *mpath;
 727         struct mpath_node *node;
 728         struct hlist_node *p;
 729         struct ieee80211_sub_if_data *sdata = sta->sdata;
 730         int i;
 731         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 732
 733         rcu_read_lock();
 734         tbl = rcu_dereference(mesh_paths);
 735         for_each_mesh_entry(tbl, p, node, i) {
 736                 mpath = node->mpath;
 737                 if (rcu_dereference(mpath->next_hop) == sta &&
 738                     mpath->flags & MESH_PATH_ACTIVE &&
 739                     !(mpath->flags & MESH_PATH_FIXED)) {
 740                         spin_lock_bh(&mpath->state_lock);
 741                         mpath->flags &= ~MESH_PATH_ACTIVE;
 742                         ++mpath->sn;
 743                         spin_unlock_bh(&mpath->state_lock);
 744                         mesh_path_error_tx(sdata,
 745                                            sdata->u.mesh.mshcfg.element_ttl,
 746                                            mpath->dst, cpu_to_le32(mpath->sn),
 747                                            reason, bcast);
 748                 }
 749         }
 750         rcu_read_unlock();
 751 }
 752
 753 static void mesh_path_node_reclaim(struct rcu_head *rp)
 754 {
 755         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 756         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 757
 758         del_timer_sync(&node->mpath->timer);
 759         atomic_dec(&sdata->u.mesh.mpaths);
 760         kfree(node->mpath);
 761         kfree(node);
 762 }
 763
 764 /* needs to be called with the corresponding hashwlock taken */
 765 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 766 {
 767         struct mesh_path *mpath;
 768         mpath = node->mpath;
 769         spin_lock(&mpath->state_lock);
 770         mpath->flags |= MESH_PATH_RESOLVING;
 771         if (mpath->is_gate)
 772                 mesh_gate_del(tbl, mpath);
 773         hlist_del_rcu(&node->list);
 774         call_rcu(&node->rcu, mesh_path_node_reclaim);
 775         spin_unlock(&mpath->state_lock);
 776         atomic_dec(&tbl->entries);
 777 }
 778
 779 /**
 780  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 781  *
 782  * @sta: mesh peer to match
 783  *
 784  * RCU notes: this function is called when a mesh plink transitions from
 785  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 786  * allows path creation. This will happen before the sta can be freed (because
 787  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 788  * protected against the plink disappearing.
 789  */
 790 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 791 {
 792         struct mesh_table *tbl;
 793         struct mesh_path *mpath;
 794         struct mpath_node *node;
 795         struct hlist_node *p;
 796         int i;
 797
 798         rcu_read_lock();
 799         read_lock_bh(&pathtbl_resize_lock);
 800         tbl = resize_dereference_mesh_paths();
 801         for_each_mesh_entry(tbl, p, node, i) {
 802                 mpath = node->mpath;
 803                 if (rcu_dereference(mpath->next_hop) == sta) {
 804                         spin_lock(&tbl->hashwlock[i]);
 805                         __mesh_path_del(tbl, node);
 806                         spin_unlock(&tbl->hashwlock[i]);
 807                 }
 808         }
 809         read_unlock_bh(&pathtbl_resize_lock);
 810         rcu_read_unlock();
 811 }
 812
 813 static void table_flush_by_iface(struct mesh_table *tbl,
 814                                  struct ieee80211_sub_if_data *sdata)
 815 {
 816         struct mesh_path *mpath;
 817         struct mpath_node *node;
 818         struct hlist_node *p;
 819         int i;
 820
 821         WARN_ON(!rcu_read_lock_held());
 822         for_each_mesh_entry(tbl, p, node, i) {
 823                 mpath = node->mpath;
 824                 if (mpath->sdata != sdata)
 825                         continue;
 826                 spin_lock_bh(&tbl->hashwlock[i]);
 827                 __mesh_path_del(tbl, node);
 828                 spin_unlock_bh(&tbl->hashwlock[i]);
 829         }
 830 }
 831
 832 /**
 833  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 834  *
 835  * This function deletes both mesh paths as well as mesh portal paths.
 836  *
 837  * @sdata: interface data to match
 838  *
 839  */
 840 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 841 {
 842         struct mesh_table *tbl;
 843
 844         rcu_read_lock();
 845         read_lock_bh(&pathtbl_resize_lock);
 846         tbl = resize_dereference_mesh_paths();
 847         table_flush_by_iface(tbl, sdata);
 848         tbl = resize_dereference_mpp_paths();
 849         table_flush_by_iface(tbl, sdata);
 850         read_unlock_bh(&pathtbl_resize_lock);
 851         rcu_read_unlock();
 852 }
 853
 854 /**
 855  * mesh_path_del - delete a mesh path from the table
 856  *
 857  * @addr: dst address (ETH_ALEN length)
 858  * @sdata: local subif
 859  *
 860  * Returns: 0 if successful
 861  */
 862 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 863 {
 864         struct mesh_table *tbl;
 865         struct mesh_path *mpath;
 866         struct mpath_node *node;
 867         struct hlist_head *bucket;
 868         struct hlist_node *n;
 869         int hash_idx;
 870         int err = 0;
 871
 872         read_lock_bh(&pathtbl_resize_lock);
 873         tbl = resize_dereference_mesh_paths();
 874         hash_idx = mesh_table_hash(addr, sdata, tbl);
 875         bucket = &tbl->hash_buckets[hash_idx];
 876
 877         spin_lock(&tbl->hashwlock[hash_idx]);
 878         hlist_for_each_entry(node, n, bucket, list) {
 879                 mpath = node->mpath;
 880                 if (mpath->sdata == sdata &&
 881                     ether_addr_equal(addr, mpath->dst)) {
 882                         __mesh_path_del(tbl, node);
 883                         goto enddel;
 884                 }
 885         }
 886
 887         err = -ENXIO;
 888 enddel:
 889         mesh_paths_generation++;
 890         spin_unlock(&tbl->hashwlock[hash_idx]);
 891         read_unlock_bh(&pathtbl_resize_lock);
 892         return err;
 893 }
 894
 895 /**
 896  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 897  *
 898  * @mpath: mesh path to activate
 899  *
 900  * Locking: the state_lock of the mpath structure must NOT be held when calling
 901  * this function.
 902  */
 903 void mesh_path_tx_pending(struct mesh_path *mpath)
 904 {
 905         if (mpath->flags & MESH_PATH_ACTIVE)
 906                 ieee80211_add_pending_skbs(mpath->sdata->local,
 907                                 &mpath->frame_queue);
 908 }
 909
 910 /**
 911  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 912  *
 913  * @mpath: mesh path whose queue will be emptied
 914  *
 915  * If there is only one gate, the frames are transferred from the failed mpath
 916  * queue to that gate's queue.  If there are more than one gates, the frames
 917  * are copied from each gate to the next.  After frames are copied, the
 918  * mpath queues are emptied onto the transmission queue.
 919  */
 920 int mesh_path_send_to_gates(struct mesh_path *mpath)
 921 {
 922         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 923         struct hlist_node *n;
 924         struct mesh_table *tbl;
 925         struct mesh_path *from_mpath = mpath;
 926         struct mpath_node *gate = NULL;
 927         bool copy = false;
 928         struct hlist_head *known_gates;
 929
 930         rcu_read_lock();
 931         tbl = rcu_dereference(mesh_paths);
 932         known_gates = tbl->known_gates;
 933         rcu_read_unlock();
 934
 935         if (!known_gates)
 936                 return -EHOSTUNREACH;
 937
 938         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
 939                 if (gate->mpath->sdata != sdata)
 940                         continue;
 941
 942                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 943                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 944                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 945                         from_mpath = gate->mpath;
 946                         copy = true;
 947                 } else {
 948                         mpath_dbg(sdata,
 949                                   "Not forwarding %p (flags %#x)\n",
 950                                   gate->mpath, gate->mpath->flags);
 951                 }
 952         }
 953
 954         hlist_for_each_entry_rcu(gate, n, known_gates, list)
 955                 if (gate->mpath->sdata == sdata) {
 956                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 957                         mesh_path_tx_pending(gate->mpath);
 958                 }
 959
 960         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 961 }
 962
 963 /**
 964  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 965  *
 966  * @skb: frame to discard
 967  * @sdata: network subif the frame was to be sent through
 968  *
 969  * Locking: the function must me called within a rcu_read_lock region
 970  */
 971 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 972                              struct sk_buff *skb)
 973 {
 974         kfree_skb(skb);
 975         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 976 }
 977
 978 /**
 979  * mesh_path_flush_pending - free the pending queue of a mesh path
 980  *
 981  * @mpath: mesh path whose queue has to be freed
 982  *
 983  * Locking: the function must me called within a rcu_read_lock region
 984  */
 985 void mesh_path_flush_pending(struct mesh_path *mpath)
 986 {
 987         struct sk_buff *skb;
 988
 989         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 990                 mesh_path_discard_frame(mpath->sdata, skb);
 991 }
 992
 993 /**
 994  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 995  *
 996  * @mpath: the mesh path to modify
 997  * @next_hop: the next hop to force
 998  *
 999  * Locking: this function must be called holding mpath->state_lock
1000  */
1001 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1002 {
1003         spin_lock_bh(&mpath->state_lock);
1004         mesh_path_assign_nexthop(mpath, next_hop);
1005         mpath->sn = 0xffff;
1006         mpath->metric = 0;
1007         mpath->hop_count = 0;
1008         mpath->exp_time = 0;
1009         mpath->flags |= MESH_PATH_FIXED;
1010         mesh_path_activate(mpath);
1011         spin_unlock_bh(&mpath->state_lock);
1012         mesh_path_tx_pending(mpath);
1013 }
1014
1015 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1016 {
1017         struct mesh_path *mpath;
1018         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1019         mpath = node->mpath;
1020         hlist_del_rcu(p);
1021         if (free_leafs) {
1022                 del_timer_sync(&mpath->timer);
1023                 kfree(mpath);
1024         }
1025         kfree(node);
1026 }
1027
1028 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1029 {
1030         struct mesh_path *mpath;
1031         struct mpath_node *node, *new_node;
1032         u32 hash_idx;
1033
1034         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1035         if (new_node == NULL)
1036                 return -ENOMEM;
1037
1038         node = hlist_entry(p, struct mpath_node, list);
1039         mpath = node->mpath;
1040         new_node->mpath = mpath;
1041         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1042         hlist_add_head(&new_node->list,
1043                         &newtbl->hash_buckets[hash_idx]);
1044         return 0;
1045 }
1046
1047 int mesh_pathtbl_init(void)
1048 {
1049         struct mesh_table *tbl_path, *tbl_mpp;
1050         int ret;
1051
1052         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1053         if (!tbl_path)
1054                 return -ENOMEM;
1055         tbl_path->free_node = &mesh_path_node_free;
1056         tbl_path->copy_node = &mesh_path_node_copy;
1057         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1058         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1059         if (!tbl_path->known_gates) {
1060                 ret = -ENOMEM;
1061                 goto free_path;
1062         }
1063         INIT_HLIST_HEAD(tbl_path->known_gates);
1064
1065
1066         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1067         if (!tbl_mpp) {
1068                 ret = -ENOMEM;
1069                 goto free_path;
1070         }
1071         tbl_mpp->free_node = &mesh_path_node_free;
1072         tbl_mpp->copy_node = &mesh_path_node_copy;
1073         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1074         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1075         if (!tbl_mpp->known_gates) {
1076                 ret = -ENOMEM;
1077                 goto free_mpp;
1078         }
1079         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1080
1081         /* Need no locking since this is during init */
1082         RCU_INIT_POINTER(mesh_paths, tbl_path);
1083         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1084
1085         return 0;
1086
1087 free_mpp:
1088         mesh_table_free(tbl_mpp, true);
1089 free_path:
1090         mesh_table_free(tbl_path, true);
1091         return ret;
1092 }
1093
1094 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1095 {
1096         struct mesh_table *tbl;
1097         struct mesh_path *mpath;
1098         struct mpath_node *node;
1099         struct hlist_node *p;
1100         int i;
1101
1102         rcu_read_lock();
1103         tbl = rcu_dereference(mesh_paths);
1104         for_each_mesh_entry(tbl, p, node, i) {
1105                 if (node->mpath->sdata != sdata)
1106                         continue;
1107                 mpath = node->mpath;
1108                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1109                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1110                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1111                         mesh_path_del(mpath->sdata, mpath->dst);
1112         }
1113         rcu_read_unlock();
1114 }
1115
1116 void mesh_pathtbl_unregister(void)
1117 {
1118         /* no need for locking during exit path */
1119         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1120         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1121 }