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 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  28                                 time_after(jiffies, mpath->exp_time) && \
  29                                 !(mpath->flags & MESH_PATH_FIXED))
  30
  31 struct mpath_node {
  32         struct hlist_node list;
  33         struct rcu_head rcu;
  34         /* This indirection allows two different tables to point to the same
  35          * mesh_path structure, useful when resizing
  36          */
  37         struct mesh_path *mpath;
  38 };
  39
  40 static struct mesh_table __rcu *mesh_paths;
  41 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  42
  43 int mesh_paths_generation;
  44
  45 /* This lock will have the grow table function as writer and add / delete nodes
  46  * as readers. RCU provides sufficient protection only when reading the table
  47  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  48  * the read lock or we risk operating on an old table.  The write lock is only
  49  * needed when modifying the number of buckets a table.
  50  */
  51 static DEFINE_RWLOCK(pathtbl_resize_lock);
  52
  53
  54 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  55 {
  56         return rcu_dereference_protected(mesh_paths,
  57                 lockdep_is_held(&pathtbl_resize_lock));
  58 }
  59
  60 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  61 {
  62         return rcu_dereference_protected(mpp_paths,
  63                 lockdep_is_held(&pathtbl_resize_lock));
  64 }
  65
  66 /*
  67  * CAREFUL -- "tbl" must not be an expression,
  68  * in particular not an rcu_dereference(), since
  69  * it's used twice. So it is illegal to do
  70  *      for_each_mesh_entry(rcu_dereference(...), ...)
  71  */
  72 #define for_each_mesh_entry(tbl, p, node, i) \
  73         for (i = 0; i <= tbl->hash_mask; i++) \
  74                 hlist_for_each_entry_rcu(node, p, &tbl->hash_buckets[i], list)
  75
  76
  77 static struct mesh_table *mesh_table_alloc(int size_order)
  78 {
  79         int i;
  80         struct mesh_table *newtbl;
  81
  82         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  83         if (!newtbl)
  84                 return NULL;
  85
  86         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  87                         (1 << size_order), GFP_ATOMIC);
  88
  89         if (!newtbl->hash_buckets) {
  90                 kfree(newtbl);
  91                 return NULL;
  92         }
  93
  94         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  95                         (1 << size_order), GFP_ATOMIC);
  96         if (!newtbl->hashwlock) {
  97                 kfree(newtbl->hash_buckets);
  98                 kfree(newtbl);
  99                 return NULL;
 100         }
 101
 102         newtbl->size_order = size_order;
 103         newtbl->hash_mask = (1 << size_order) - 1;
 104         atomic_set(&newtbl->entries,  0);
 105         get_random_bytes(&newtbl->hash_rnd,
 106                         sizeof(newtbl->hash_rnd));
 107         for (i = 0; i <= newtbl->hash_mask; i++)
 108                 spin_lock_init(&newtbl->hashwlock[i]);
 109         spin_lock_init(&newtbl->gates_lock);
 110
 111         return newtbl;
 112 }
 113
 114 static void __mesh_table_free(struct mesh_table *tbl)
 115 {
 116         kfree(tbl->hash_buckets);
 117         kfree(tbl->hashwlock);
 118         kfree(tbl);
 119 }
 120
 121 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 122 {
 123         struct hlist_head *mesh_hash;
 124         struct hlist_node *p, *q;
 125         struct mpath_node *gate;
 126         int i;
 127
 128         mesh_hash = tbl->hash_buckets;
 129         for (i = 0; i <= tbl->hash_mask; i++) {
 130                 spin_lock_bh(&tbl->hashwlock[i]);
 131                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 132                         tbl->free_node(p, free_leafs);
 133                         atomic_dec(&tbl->entries);
 134                 }
 135                 spin_unlock_bh(&tbl->hashwlock[i]);
 136         }
 137         if (free_leafs) {
 138                 spin_lock_bh(&tbl->gates_lock);
 139                 hlist_for_each_entry_safe(gate, p, q,
 140                                          tbl->known_gates, list) {
 141                         hlist_del(&gate->list);
 142                         kfree(gate);
 143                 }
 144                 kfree(tbl->known_gates);
 145                 spin_unlock_bh(&tbl->gates_lock);
 146         }
 147
 148         __mesh_table_free(tbl);
 149 }
 150
 151 static int mesh_table_grow(struct mesh_table *oldtbl,
 152                            struct mesh_table *newtbl)
 153 {
 154         struct hlist_head *oldhash;
 155         struct hlist_node *p, *q;
 156         int i;
 157
 158         if (atomic_read(&oldtbl->entries)
 159                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 160                 return -EAGAIN;
 161
 162         newtbl->free_node = oldtbl->free_node;
 163         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 164         newtbl->copy_node = oldtbl->copy_node;
 165         newtbl->known_gates = oldtbl->known_gates;
 166         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 167
 168         oldhash = oldtbl->hash_buckets;
 169         for (i = 0; i <= oldtbl->hash_mask; i++)
 170                 hlist_for_each(p, &oldhash[i])
 171                         if (oldtbl->copy_node(p, newtbl) < 0)
 172                                 goto errcopy;
 173
 174         return 0;
 175
 176 errcopy:
 177         for (i = 0; i <= newtbl->hash_mask; i++) {
 178                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 179                         oldtbl->free_node(p, 0);
 180         }
 181         return -ENOMEM;
 182 }
 183
 184 static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
 185                            struct mesh_table *tbl)
 186 {
 187         /* Use last four bytes of hw addr and interface index as hash index */
 188         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
 189                 & tbl->hash_mask;
 190 }
 191
 192
 193 /**
 194  *
 195  * mesh_path_assign_nexthop - update mesh path next hop
 196  *
 197  * @mpath: mesh path to update
 198  * @sta: next hop to assign
 199  *
 200  * Locking: mpath->state_lock must be held when calling this function
 201  */
 202 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 203 {
 204         struct sk_buff *skb;
 205         struct ieee80211_hdr *hdr;
 206         unsigned long flags;
 207
 208         rcu_assign_pointer(mpath->next_hop, sta);
 209
 210         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 211         skb_queue_walk(&mpath->frame_queue, skb) {
 212                 hdr = (struct ieee80211_hdr *) skb->data;
 213                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 214                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 215         }
 216
 217         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 218 }
 219
 220 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 221                              struct mesh_path *gate_mpath)
 222 {
 223         struct ieee80211_hdr *hdr;
 224         struct ieee80211s_hdr *mshdr;
 225         int mesh_hdrlen, hdrlen;
 226         char *next_hop;
 227
 228         hdr = (struct ieee80211_hdr *) skb->data;
 229         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 230         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 231
 232         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 233                 /* size of the fixed part of the mesh header */
 234                 mesh_hdrlen = 6;
 235
 236                 /* make room for the two extended addresses */
 237                 skb_push(skb, 2 * ETH_ALEN);
 238                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 239
 240                 hdr = (struct ieee80211_hdr *) skb->data;
 241
 242                 /* we preserve the previous mesh header and only add
 243                  * the new addreses */
 244                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 245                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 246                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 247                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 248         }
 249
 250         /* update next hop */
 251         hdr = (struct ieee80211_hdr *) skb->data;
 252         rcu_read_lock();
 253         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 254         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 255         rcu_read_unlock();
 256         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 257         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 258 }
 259
 260 /**
 261  *
 262  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 263  *
 264  * This function is used to transfer or copy frames from an unresolved mpath to
 265  * a gate mpath.  The function also adds the Address Extension field and
 266  * updates the next hop.
 267  *
 268  * If a frame already has an Address Extension field, only the next hop and
 269  * destination addresses are updated.
 270  *
 271  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 272  *
 273  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 274  * @from_mpath: The failed mpath
 275  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 276  * move them.
 277  */
 278 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 279                                     struct mesh_path *from_mpath,
 280                                     bool copy)
 281 {
 282         struct sk_buff *skb, *fskb, *tmp;
 283         struct sk_buff_head failq;
 284         unsigned long flags;
 285
 286         BUG_ON(gate_mpath == from_mpath);
 287         BUG_ON(!gate_mpath->next_hop);
 288
 289         __skb_queue_head_init(&failq);
 290
 291         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 292         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 293         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 294
 295         skb_queue_walk_safe(&failq, fskb, tmp) {
 296                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 297                                   MESH_FRAME_QUEUE_LEN) {
 298                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 299                         break;
 300                 }
 301
 302                 skb = skb_copy(fskb, GFP_ATOMIC);
 303                 if (WARN_ON(!skb))
 304                         break;
 305
 306                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 307                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 308
 309                 if (copy)
 310                         continue;
 311
 312                 __skb_unlink(fskb, &failq);
 313                 kfree_skb(fskb);
 314         }
 315
 316         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 317                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 318
 319         if (!copy)
 320                 return;
 321
 322         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 323         skb_queue_splice(&failq, &from_mpath->frame_queue);
 324         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 325 }
 326
 327
 328 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, u8 *dst,
 329                                           struct ieee80211_sub_if_data *sdata)
 330 {
 331         struct mesh_path *mpath;
 332         struct hlist_node *n;
 333         struct hlist_head *bucket;
 334         struct mpath_node *node;
 335
 336         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 337         hlist_for_each_entry_rcu(node, n, bucket, list) {
 338                 mpath = node->mpath;
 339                 if (mpath->sdata == sdata &&
 340                     ether_addr_equal(dst, mpath->dst)) {
 341                         if (MPATH_EXPIRED(mpath)) {
 342                                 spin_lock_bh(&mpath->state_lock);
 343                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 344                                 spin_unlock_bh(&mpath->state_lock);
 345                         }
 346                         return mpath;
 347                 }
 348         }
 349         return NULL;
 350 }
 351
 352 /**
 353  * mesh_path_lookup - look up a path in the mesh path table
 354  * @dst: hardware address (ETH_ALEN length) of destination
 355  * @sdata: local subif
 356  *
 357  * Returns: pointer to the mesh path structure, or NULL if not found
 358  *
 359  * Locking: must be called within a read rcu section.
 360  */
 361 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 362 {
 363         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 364 }
 365
 366 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 367 {
 368         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 369 }
 370
 371
 372 /**
 373  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 374  * @idx: index
 375  * @sdata: local subif, or NULL for all entries
 376  *
 377  * Returns: pointer to the mesh path structure, or NULL if not found.
 378  *
 379  * Locking: must be called within a read rcu section.
 380  */
 381 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 382 {
 383         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 384         struct mpath_node *node;
 385         struct hlist_node *p;
 386         int i;
 387         int j = 0;
 388
 389         for_each_mesh_entry(tbl, p, node, i) {
 390                 if (sdata && node->mpath->sdata != sdata)
 391                         continue;
 392                 if (j++ == idx) {
 393                         if (MPATH_EXPIRED(node->mpath)) {
 394                                 spin_lock_bh(&node->mpath->state_lock);
 395                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 396                                 spin_unlock_bh(&node->mpath->state_lock);
 397                         }
 398                         return node->mpath;
 399                 }
 400         }
 401
 402         return NULL;
 403 }
 404
 405 /**
 406  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 407  * @mpath: gate path to add to table
 408  */
 409 int mesh_path_add_gate(struct mesh_path *mpath)
 410 {
 411         struct mesh_table *tbl;
 412         struct mpath_node *gate, *new_gate;
 413         struct hlist_node *n;
 414         int err;
 415
 416         rcu_read_lock();
 417         tbl = rcu_dereference(mesh_paths);
 418
 419         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
 420                 if (gate->mpath == mpath) {
 421                         err = -EEXIST;
 422                         goto err_rcu;
 423                 }
 424
 425         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 426         if (!new_gate) {
 427                 err = -ENOMEM;
 428                 goto err_rcu;
 429         }
 430
 431         mpath->is_gate = true;
 432         mpath->sdata->u.mesh.num_gates++;
 433         new_gate->mpath = mpath;
 434         spin_lock_bh(&tbl->gates_lock);
 435         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 436         spin_unlock_bh(&tbl->gates_lock);
 437         rcu_read_unlock();
 438         mpath_dbg(mpath->sdata,
 439                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 440                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 441         return 0;
 442 err_rcu:
 443         rcu_read_unlock();
 444         return err;
 445 }
 446
 447 /**
 448  * mesh_gate_del - remove a mesh gate from the list of known gates
 449  * @tbl: table which holds our list of known gates
 450  * @mpath: gate mpath
 451  *
 452  * Returns: 0 on success
 453  *
 454  * Locking: must be called inside rcu_read_lock() section
 455  */
 456 static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 457 {
 458         struct mpath_node *gate;
 459         struct hlist_node *p, *q;
 460
 461         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list)
 462                 if (gate->mpath == mpath) {
 463                         spin_lock_bh(&tbl->gates_lock);
 464                         hlist_del_rcu(&gate->list);
 465                         kfree_rcu(gate, rcu);
 466                         spin_unlock_bh(&tbl->gates_lock);
 467                         mpath->sdata->u.mesh.num_gates--;
 468                         mpath->is_gate = false;
 469                         mpath_dbg(mpath->sdata,
 470                                   "Mesh path: Deleted gate: %pM. %d known gates\n",
 471                                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 472                         break;
 473                 }
 474
 475         return 0;
 476 }
 477
 478 /**
 479  * mesh_gate_num - number of gates known to this interface
 480  * @sdata: subif data
 481  */
 482 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 483 {
 484         return sdata->u.mesh.num_gates;
 485 }
 486
 487 /**
 488  * mesh_path_add - allocate and add a new path to the mesh path table
 489  * @addr: destination address of the path (ETH_ALEN length)
 490  * @sdata: local subif
 491  *
 492  * Returns: 0 on success
 493  *
 494  * State: the initial state of the new path is set to 0
 495  */
 496 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 497 {
 498         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 499         struct ieee80211_local *local = sdata->local;
 500         struct mesh_table *tbl;
 501         struct mesh_path *mpath, *new_mpath;
 502         struct mpath_node *node, *new_node;
 503         struct hlist_head *bucket;
 504         struct hlist_node *n;
 505         int grow = 0;
 506         int err = 0;
 507         u32 hash_idx;
 508
 509         if (ether_addr_equal(dst, sdata->vif.addr))
 510                 /* never add ourselves as neighbours */
 511                 return -ENOTSUPP;
 512
 513         if (is_multicast_ether_addr(dst))
 514                 return -ENOTSUPP;
 515
 516         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 517                 return -ENOSPC;
 518
 519         err = -ENOMEM;
 520         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 521         if (!new_mpath)
 522                 goto err_path_alloc;
 523
 524         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 525         if (!new_node)
 526                 goto err_node_alloc;
 527
 528         read_lock_bh(&pathtbl_resize_lock);
 529         memcpy(new_mpath->dst, dst, ETH_ALEN);
 530         eth_broadcast_addr(new_mpath->rann_snd_addr);
 531         new_mpath->is_root = false;
 532         new_mpath->sdata = sdata;
 533         new_mpath->flags = 0;
 534         skb_queue_head_init(&new_mpath->frame_queue);
 535         new_node->mpath = new_mpath;
 536         new_mpath->timer.data = (unsigned long) new_mpath;
 537         new_mpath->timer.function = mesh_path_timer;
 538         new_mpath->exp_time = jiffies;
 539         spin_lock_init(&new_mpath->state_lock);
 540         init_timer(&new_mpath->timer);
 541
 542         tbl = resize_dereference_mesh_paths();
 543
 544         hash_idx = mesh_table_hash(dst, sdata, tbl);
 545         bucket = &tbl->hash_buckets[hash_idx];
 546
 547         spin_lock(&tbl->hashwlock[hash_idx]);
 548
 549         err = -EEXIST;
 550         hlist_for_each_entry(node, n, bucket, list) {
 551                 mpath = node->mpath;
 552                 if (mpath->sdata == sdata &&
 553                     ether_addr_equal(dst, mpath->dst))
 554                         goto err_exists;
 555         }
 556
 557         hlist_add_head_rcu(&new_node->list, bucket);
 558         if (atomic_inc_return(&tbl->entries) >=
 559             tbl->mean_chain_len * (tbl->hash_mask + 1))
 560                 grow = 1;
 561
 562         mesh_paths_generation++;
 563
 564         spin_unlock(&tbl->hashwlock[hash_idx]);
 565         read_unlock_bh(&pathtbl_resize_lock);
 566         if (grow) {
 567                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 568                 ieee80211_queue_work(&local->hw, &sdata->work);
 569         }
 570         return 0;
 571
 572 err_exists:
 573         spin_unlock(&tbl->hashwlock[hash_idx]);
 574         read_unlock_bh(&pathtbl_resize_lock);
 575         kfree(new_node);
 576 err_node_alloc:
 577         kfree(new_mpath);
 578 err_path_alloc:
 579         atomic_dec(&sdata->u.mesh.mpaths);
 580         return err;
 581 }
 582
 583 static void mesh_table_free_rcu(struct rcu_head *rcu)
 584 {
 585         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 586
 587         mesh_table_free(tbl, false);
 588 }
 589
 590 void mesh_mpath_table_grow(void)
 591 {
 592         struct mesh_table *oldtbl, *newtbl;
 593
 594         write_lock_bh(&pathtbl_resize_lock);
 595         oldtbl = resize_dereference_mesh_paths();
 596         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 597         if (!newtbl)
 598                 goto out;
 599         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 600                 __mesh_table_free(newtbl);
 601                 goto out;
 602         }
 603         rcu_assign_pointer(mesh_paths, newtbl);
 604
 605         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 606
 607  out:
 608         write_unlock_bh(&pathtbl_resize_lock);
 609 }
 610
 611 void mesh_mpp_table_grow(void)
 612 {
 613         struct mesh_table *oldtbl, *newtbl;
 614
 615         write_lock_bh(&pathtbl_resize_lock);
 616         oldtbl = resize_dereference_mpp_paths();
 617         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 618         if (!newtbl)
 619                 goto out;
 620         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 621                 __mesh_table_free(newtbl);
 622                 goto out;
 623         }
 624         rcu_assign_pointer(mpp_paths, newtbl);
 625         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 626
 627  out:
 628         write_unlock_bh(&pathtbl_resize_lock);
 629 }
 630
 631 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 632 {
 633         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 634         struct ieee80211_local *local = sdata->local;
 635         struct mesh_table *tbl;
 636         struct mesh_path *mpath, *new_mpath;
 637         struct mpath_node *node, *new_node;
 638         struct hlist_head *bucket;
 639         struct hlist_node *n;
 640         int grow = 0;
 641         int err = 0;
 642         u32 hash_idx;
 643
 644         if (ether_addr_equal(dst, sdata->vif.addr))
 645                 /* never add ourselves as neighbours */
 646                 return -ENOTSUPP;
 647
 648         if (is_multicast_ether_addr(dst))
 649                 return -ENOTSUPP;
 650
 651         err = -ENOMEM;
 652         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 653         if (!new_mpath)
 654                 goto err_path_alloc;
 655
 656         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 657         if (!new_node)
 658                 goto err_node_alloc;
 659
 660         read_lock_bh(&pathtbl_resize_lock);
 661         memcpy(new_mpath->dst, dst, ETH_ALEN);
 662         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 663         new_mpath->sdata = sdata;
 664         new_mpath->flags = 0;
 665         skb_queue_head_init(&new_mpath->frame_queue);
 666         new_node->mpath = new_mpath;
 667         init_timer(&new_mpath->timer);
 668         new_mpath->exp_time = jiffies;
 669         spin_lock_init(&new_mpath->state_lock);
 670
 671         tbl = resize_dereference_mpp_paths();
 672
 673         hash_idx = mesh_table_hash(dst, sdata, tbl);
 674         bucket = &tbl->hash_buckets[hash_idx];
 675
 676         spin_lock(&tbl->hashwlock[hash_idx]);
 677
 678         err = -EEXIST;
 679         hlist_for_each_entry(node, n, bucket, list) {
 680                 mpath = node->mpath;
 681                 if (mpath->sdata == sdata &&
 682                     ether_addr_equal(dst, mpath->dst))
 683                         goto err_exists;
 684         }
 685
 686         hlist_add_head_rcu(&new_node->list, bucket);
 687         if (atomic_inc_return(&tbl->entries) >=
 688             tbl->mean_chain_len * (tbl->hash_mask + 1))
 689                 grow = 1;
 690
 691         spin_unlock(&tbl->hashwlock[hash_idx]);
 692         read_unlock_bh(&pathtbl_resize_lock);
 693         if (grow) {
 694                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 695                 ieee80211_queue_work(&local->hw, &sdata->work);
 696         }
 697         return 0;
 698
 699 err_exists:
 700         spin_unlock(&tbl->hashwlock[hash_idx]);
 701         read_unlock_bh(&pathtbl_resize_lock);
 702         kfree(new_node);
 703 err_node_alloc:
 704         kfree(new_mpath);
 705 err_path_alloc:
 706         return err;
 707 }
 708
 709
 710 /**
 711  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 712  *
 713  * @sta: broken peer link
 714  *
 715  * This function must be called from the rate control algorithm if enough
 716  * delivery errors suggest that a peer link is no longer usable.
 717  */
 718 void mesh_plink_broken(struct sta_info *sta)
 719 {
 720         struct mesh_table *tbl;
 721         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 722         struct mesh_path *mpath;
 723         struct mpath_node *node;
 724         struct hlist_node *p;
 725         struct ieee80211_sub_if_data *sdata = sta->sdata;
 726         int i;
 727         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 728
 729         rcu_read_lock();
 730         tbl = rcu_dereference(mesh_paths);
 731         for_each_mesh_entry(tbl, p, node, i) {
 732                 mpath = node->mpath;
 733                 if (rcu_dereference(mpath->next_hop) == sta &&
 734                     mpath->flags & MESH_PATH_ACTIVE &&
 735                     !(mpath->flags & MESH_PATH_FIXED)) {
 736                         spin_lock_bh(&mpath->state_lock);
 737                         mpath->flags &= ~MESH_PATH_ACTIVE;
 738                         ++mpath->sn;
 739                         spin_unlock_bh(&mpath->state_lock);
 740                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 741                                         mpath->dst, cpu_to_le32(mpath->sn),
 742                                         reason, bcast, sdata);
 743                 }
 744         }
 745         rcu_read_unlock();
 746 }
 747
 748 static void mesh_path_node_reclaim(struct rcu_head *rp)
 749 {
 750         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 751         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 752
 753         del_timer_sync(&node->mpath->timer);
 754         atomic_dec(&sdata->u.mesh.mpaths);
 755         kfree(node->mpath);
 756         kfree(node);
 757 }
 758
 759 /* needs to be called with the corresponding hashwlock taken */
 760 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 761 {
 762         struct mesh_path *mpath;
 763         mpath = node->mpath;
 764         spin_lock(&mpath->state_lock);
 765         mpath->flags |= MESH_PATH_RESOLVING;
 766         if (mpath->is_gate)
 767                 mesh_gate_del(tbl, mpath);
 768         hlist_del_rcu(&node->list);
 769         call_rcu(&node->rcu, mesh_path_node_reclaim);
 770         spin_unlock(&mpath->state_lock);
 771         atomic_dec(&tbl->entries);
 772 }
 773
 774 /**
 775  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 776  *
 777  * @sta: mesh peer to match
 778  *
 779  * RCU notes: this function is called when a mesh plink transitions from
 780  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 781  * allows path creation. This will happen before the sta can be freed (because
 782  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 783  * protected against the plink disappearing.
 784  */
 785 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 786 {
 787         struct mesh_table *tbl;
 788         struct mesh_path *mpath;
 789         struct mpath_node *node;
 790         struct hlist_node *p;
 791         int i;
 792
 793         rcu_read_lock();
 794         read_lock_bh(&pathtbl_resize_lock);
 795         tbl = resize_dereference_mesh_paths();
 796         for_each_mesh_entry(tbl, p, node, i) {
 797                 mpath = node->mpath;
 798                 if (rcu_dereference(mpath->next_hop) == sta) {
 799                         spin_lock(&tbl->hashwlock[i]);
 800                         __mesh_path_del(tbl, node);
 801                         spin_unlock(&tbl->hashwlock[i]);
 802                 }
 803         }
 804         read_unlock_bh(&pathtbl_resize_lock);
 805         rcu_read_unlock();
 806 }
 807
 808 static void table_flush_by_iface(struct mesh_table *tbl,
 809                                  struct ieee80211_sub_if_data *sdata)
 810 {
 811         struct mesh_path *mpath;
 812         struct mpath_node *node;
 813         struct hlist_node *p;
 814         int i;
 815
 816         WARN_ON(!rcu_read_lock_held());
 817         for_each_mesh_entry(tbl, p, node, i) {
 818                 mpath = node->mpath;
 819                 if (mpath->sdata != sdata)
 820                         continue;
 821                 spin_lock_bh(&tbl->hashwlock[i]);
 822                 __mesh_path_del(tbl, node);
 823                 spin_unlock_bh(&tbl->hashwlock[i]);
 824         }
 825 }
 826
 827 /**
 828  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 829  *
 830  * This function deletes both mesh paths as well as mesh portal paths.
 831  *
 832  * @sdata: interface data to match
 833  *
 834  */
 835 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 836 {
 837         struct mesh_table *tbl;
 838
 839         rcu_read_lock();
 840         read_lock_bh(&pathtbl_resize_lock);
 841         tbl = resize_dereference_mesh_paths();
 842         table_flush_by_iface(tbl, sdata);
 843         tbl = resize_dereference_mpp_paths();
 844         table_flush_by_iface(tbl, sdata);
 845         read_unlock_bh(&pathtbl_resize_lock);
 846         rcu_read_unlock();
 847 }
 848
 849 /**
 850  * mesh_path_del - delete a mesh path from the table
 851  *
 852  * @addr: dst address (ETH_ALEN length)
 853  * @sdata: local subif
 854  *
 855  * Returns: 0 if successful
 856  */
 857 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 858 {
 859         struct mesh_table *tbl;
 860         struct mesh_path *mpath;
 861         struct mpath_node *node;
 862         struct hlist_head *bucket;
 863         struct hlist_node *n;
 864         int hash_idx;
 865         int err = 0;
 866
 867         read_lock_bh(&pathtbl_resize_lock);
 868         tbl = resize_dereference_mesh_paths();
 869         hash_idx = mesh_table_hash(addr, sdata, tbl);
 870         bucket = &tbl->hash_buckets[hash_idx];
 871
 872         spin_lock(&tbl->hashwlock[hash_idx]);
 873         hlist_for_each_entry(node, n, bucket, list) {
 874                 mpath = node->mpath;
 875                 if (mpath->sdata == sdata &&
 876                     ether_addr_equal(addr, mpath->dst)) {
 877                         __mesh_path_del(tbl, node);
 878                         goto enddel;
 879                 }
 880         }
 881
 882         err = -ENXIO;
 883 enddel:
 884         mesh_paths_generation++;
 885         spin_unlock(&tbl->hashwlock[hash_idx]);
 886         read_unlock_bh(&pathtbl_resize_lock);
 887         return err;
 888 }
 889
 890 /**
 891  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 892  *
 893  * @mpath: mesh path to activate
 894  *
 895  * Locking: the state_lock of the mpath structure must NOT be held when calling
 896  * this function.
 897  */
 898 void mesh_path_tx_pending(struct mesh_path *mpath)
 899 {
 900         if (mpath->flags & MESH_PATH_ACTIVE)
 901                 ieee80211_add_pending_skbs(mpath->sdata->local,
 902                                 &mpath->frame_queue);
 903 }
 904
 905 /**
 906  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 907  *
 908  * @mpath: mesh path whose queue will be emptied
 909  *
 910  * If there is only one gate, the frames are transferred from the failed mpath
 911  * queue to that gate's queue.  If there are more than one gates, the frames
 912  * are copied from each gate to the next.  After frames are copied, the
 913  * mpath queues are emptied onto the transmission queue.
 914  */
 915 int mesh_path_send_to_gates(struct mesh_path *mpath)
 916 {
 917         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 918         struct hlist_node *n;
 919         struct mesh_table *tbl;
 920         struct mesh_path *from_mpath = mpath;
 921         struct mpath_node *gate = NULL;
 922         bool copy = false;
 923         struct hlist_head *known_gates;
 924
 925         rcu_read_lock();
 926         tbl = rcu_dereference(mesh_paths);
 927         known_gates = tbl->known_gates;
 928         rcu_read_unlock();
 929
 930         if (!known_gates)
 931                 return -EHOSTUNREACH;
 932
 933         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
 934                 if (gate->mpath->sdata != sdata)
 935                         continue;
 936
 937                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 938                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 939                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 940                         from_mpath = gate->mpath;
 941                         copy = true;
 942                 } else {
 943                         mpath_dbg(sdata,
 944                                   "Not forwarding %p (flags %#x)\n",
 945                                   gate->mpath, gate->mpath->flags);
 946                 }
 947         }
 948
 949         hlist_for_each_entry_rcu(gate, n, known_gates, list)
 950                 if (gate->mpath->sdata == sdata) {
 951                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 952                         mesh_path_tx_pending(gate->mpath);
 953                 }
 954
 955         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 956 }
 957
 958 /**
 959  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 960  *
 961  * @skb: frame to discard
 962  * @sdata: network subif the frame was to be sent through
 963  *
 964  * Locking: the function must me called within a rcu_read_lock region
 965  */
 966 void mesh_path_discard_frame(struct sk_buff *skb,
 967                              struct ieee80211_sub_if_data *sdata)
 968 {
 969         kfree_skb(skb);
 970         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 971 }
 972
 973 /**
 974  * mesh_path_flush_pending - free the pending queue of a mesh path
 975  *
 976  * @mpath: mesh path whose queue has to be freed
 977  *
 978  * Locking: the function must me called within a rcu_read_lock region
 979  */
 980 void mesh_path_flush_pending(struct mesh_path *mpath)
 981 {
 982         struct sk_buff *skb;
 983
 984         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 985                 mesh_path_discard_frame(skb, mpath->sdata);
 986 }
 987
 988 /**
 989  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 990  *
 991  * @mpath: the mesh path to modify
 992  * @next_hop: the next hop to force
 993  *
 994  * Locking: this function must be called holding mpath->state_lock
 995  */
 996 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 997 {
 998         spin_lock_bh(&mpath->state_lock);
 999         mesh_path_assign_nexthop(mpath, next_hop);
1000         mpath->sn = 0xffff;
1001         mpath->metric = 0;
1002         mpath->hop_count = 0;
1003         mpath->exp_time = 0;
1004         mpath->flags |= MESH_PATH_FIXED;
1005         mesh_path_activate(mpath);
1006         spin_unlock_bh(&mpath->state_lock);
1007         mesh_path_tx_pending(mpath);
1008 }
1009
1010 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1011 {
1012         struct mesh_path *mpath;
1013         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1014         mpath = node->mpath;
1015         hlist_del_rcu(p);
1016         if (free_leafs) {
1017                 del_timer_sync(&mpath->timer);
1018                 kfree(mpath);
1019         }
1020         kfree(node);
1021 }
1022
1023 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1024 {
1025         struct mesh_path *mpath;
1026         struct mpath_node *node, *new_node;
1027         u32 hash_idx;
1028
1029         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1030         if (new_node == NULL)
1031                 return -ENOMEM;
1032
1033         node = hlist_entry(p, struct mpath_node, list);
1034         mpath = node->mpath;
1035         new_node->mpath = mpath;
1036         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1037         hlist_add_head(&new_node->list,
1038                         &newtbl->hash_buckets[hash_idx]);
1039         return 0;
1040 }
1041
1042 int mesh_pathtbl_init(void)
1043 {
1044         struct mesh_table *tbl_path, *tbl_mpp;
1045         int ret;
1046
1047         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1048         if (!tbl_path)
1049                 return -ENOMEM;
1050         tbl_path->free_node = &mesh_path_node_free;
1051         tbl_path->copy_node = &mesh_path_node_copy;
1052         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1053         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1054         if (!tbl_path->known_gates) {
1055                 ret = -ENOMEM;
1056                 goto free_path;
1057         }
1058         INIT_HLIST_HEAD(tbl_path->known_gates);
1059
1060
1061         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1062         if (!tbl_mpp) {
1063                 ret = -ENOMEM;
1064                 goto free_path;
1065         }
1066         tbl_mpp->free_node = &mesh_path_node_free;
1067         tbl_mpp->copy_node = &mesh_path_node_copy;
1068         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1069         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1070         if (!tbl_mpp->known_gates) {
1071                 ret = -ENOMEM;
1072                 goto free_mpp;
1073         }
1074         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1075
1076         /* Need no locking since this is during init */
1077         RCU_INIT_POINTER(mesh_paths, tbl_path);
1078         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1079
1080         return 0;
1081
1082 free_mpp:
1083         mesh_table_free(tbl_mpp, true);
1084 free_path:
1085         mesh_table_free(tbl_path, true);
1086         return ret;
1087 }
1088
1089 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1090 {
1091         struct mesh_table *tbl;
1092         struct mesh_path *mpath;
1093         struct mpath_node *node;
1094         struct hlist_node *p;
1095         int i;
1096
1097         rcu_read_lock();
1098         tbl = rcu_dereference(mesh_paths);
1099         for_each_mesh_entry(tbl, p, node, i) {
1100                 if (node->mpath->sdata != sdata)
1101                         continue;
1102                 mpath = node->mpath;
1103                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1104                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1105                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1106                         mesh_path_del(mpath->dst, mpath->sdata);
1107         }
1108         rcu_read_unlock();
1109 }
1110
1111 void mesh_pathtbl_unregister(void)
1112 {
1113         /* no need for locking during exit path */
1114         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1115         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1116 }