kernel/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 int mpp_paths_generation;
  48
  49 /* This lock will have the grow table function as writer and add / delete nodes
  50  * as readers. RCU provides sufficient protection only when reading the table
  51  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  52  * the read lock or we risk operating on an old table.  The write lock is only
  53  * needed when modifying the number of buckets a table.
  54  */
  55 static DEFINE_RWLOCK(pathtbl_resize_lock);
  56
  57
  58 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  59 {
  60         return rcu_dereference_protected(mesh_paths,
  61                 lockdep_is_held(&pathtbl_resize_lock));
  62 }
  63
  64 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  65 {
  66         return rcu_dereference_protected(mpp_paths,
  67                 lockdep_is_held(&pathtbl_resize_lock));
  68 }
  69
  70 /*
  71  * CAREFUL -- "tbl" must not be an expression,
  72  * in particular not an rcu_dereference(), since
  73  * it's used twice. So it is illegal to do
  74  *      for_each_mesh_entry(rcu_dereference(...), ...)
  75  */
  76 #define for_each_mesh_entry(tbl, node, i) \
  77         for (i = 0; i <= tbl->hash_mask; i++) \
  78                 hlist_for_each_entry_rcu(node, &tbl->hash_buckets[i], list)
  79
  80
  81 static struct mesh_table *mesh_table_alloc(int size_order)
  82 {
  83         int i;
  84         struct mesh_table *newtbl;
  85
  86         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  87         if (!newtbl)
  88                 return NULL;
  89
  90         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  91                         (1 << size_order), GFP_ATOMIC);
  92
  93         if (!newtbl->hash_buckets) {
  94                 kfree(newtbl);
  95                 return NULL;
  96         }
  97
  98         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  99                         (1 << size_order), GFP_ATOMIC);
 100         if (!newtbl->hashwlock) {
 101                 kfree(newtbl->hash_buckets);
 102                 kfree(newtbl);
 103                 return NULL;
 104         }
 105
 106         newtbl->size_order = size_order;
 107         newtbl->hash_mask = (1 << size_order) - 1;
 108         atomic_set(&newtbl->entries,  0);
 109         get_random_bytes(&newtbl->hash_rnd,
 110                         sizeof(newtbl->hash_rnd));
 111         for (i = 0; i <= newtbl->hash_mask; i++)
 112                 spin_lock_init(&newtbl->hashwlock[i]);
 113         spin_lock_init(&newtbl->gates_lock);
 114
 115         return newtbl;
 116 }
 117
 118 static void __mesh_table_free(struct mesh_table *tbl)
 119 {
 120         kfree(tbl->hash_buckets);
 121         kfree(tbl->hashwlock);
 122         kfree(tbl);
 123 }
 124
 125 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 126 {
 127         struct hlist_head *mesh_hash;
 128         struct hlist_node *p, *q;
 129         struct mpath_node *gate;
 130         int i;
 131
 132         mesh_hash = tbl->hash_buckets;
 133         for (i = 0; i <= tbl->hash_mask; i++) {
 134                 spin_lock_bh(&tbl->hashwlock[i]);
 135                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 136                         tbl->free_node(p, free_leafs);
 137                         atomic_dec(&tbl->entries);
 138                 }
 139                 spin_unlock_bh(&tbl->hashwlock[i]);
 140         }
 141         if (free_leafs) {
 142                 spin_lock_bh(&tbl->gates_lock);
 143                 hlist_for_each_entry_safe(gate, q,
 144                                          tbl->known_gates, list) {
 145                         hlist_del(&gate->list);
 146                         kfree(gate);
 147                 }
 148                 kfree(tbl->known_gates);
 149                 spin_unlock_bh(&tbl->gates_lock);
 150         }
 151
 152         __mesh_table_free(tbl);
 153 }
 154
 155 static int mesh_table_grow(struct mesh_table *oldtbl,
 156                            struct mesh_table *newtbl)
 157 {
 158         struct hlist_head *oldhash;
 159         struct hlist_node *p, *q;
 160         int i;
 161
 162         if (atomic_read(&oldtbl->entries)
 163                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 164                 return -EAGAIN;
 165
 166         newtbl->free_node = oldtbl->free_node;
 167         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 168         newtbl->copy_node = oldtbl->copy_node;
 169         newtbl->known_gates = oldtbl->known_gates;
 170         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 171
 172         oldhash = oldtbl->hash_buckets;
 173         for (i = 0; i <= oldtbl->hash_mask; i++)
 174                 hlist_for_each(p, &oldhash[i])
 175                         if (oldtbl->copy_node(p, newtbl) < 0)
 176                                 goto errcopy;
 177
 178         return 0;
 179
 180 errcopy:
 181         for (i = 0; i <= newtbl->hash_mask; i++) {
 182                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 183                         oldtbl->free_node(p, 0);
 184         }
 185         return -ENOMEM;
 186 }
 187
 188 static u32 mesh_table_hash(const u8 *addr, struct ieee80211_sub_if_data *sdata,
 189                            struct mesh_table *tbl)
 190 {
 191         /* Use last four bytes of hw addr and interface index as hash index */
 192         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex,
 193                             tbl->hash_rnd) & tbl->hash_mask;
 194 }
 195
 196
 197 /**
 198  *
 199  * mesh_path_assign_nexthop - update mesh path next hop
 200  *
 201  * @mpath: mesh path to update
 202  * @sta: next hop to assign
 203  *
 204  * Locking: mpath->state_lock must be held when calling this function
 205  */
 206 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 207 {
 208         struct sk_buff *skb;
 209         struct ieee80211_hdr *hdr;
 210         unsigned long flags;
 211
 212         rcu_assign_pointer(mpath->next_hop, sta);
 213
 214         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 215         skb_queue_walk(&mpath->frame_queue, skb) {
 216                 hdr = (struct ieee80211_hdr *) skb->data;
 217                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 218                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 219                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 220         }
 221
 222         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 223 }
 224
 225 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 226                              struct mesh_path *gate_mpath)
 227 {
 228         struct ieee80211_hdr *hdr;
 229         struct ieee80211s_hdr *mshdr;
 230         int mesh_hdrlen, hdrlen;
 231         char *next_hop;
 232
 233         hdr = (struct ieee80211_hdr *) skb->data;
 234         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 235         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 236
 237         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 238                 /* size of the fixed part of the mesh header */
 239                 mesh_hdrlen = 6;
 240
 241                 /* make room for the two extended addresses */
 242                 skb_push(skb, 2 * ETH_ALEN);
 243                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 244
 245                 hdr = (struct ieee80211_hdr *) skb->data;
 246
 247                 /* we preserve the previous mesh header and only add
 248                  * the new addreses */
 249                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 250                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 251                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 252                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 253         }
 254
 255         /* update next hop */
 256         hdr = (struct ieee80211_hdr *) skb->data;
 257         rcu_read_lock();
 258         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 259         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 260         rcu_read_unlock();
 261         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 262         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 263 }
 264
 265 /**
 266  *
 267  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 268  *
 269  * This function is used to transfer or copy frames from an unresolved mpath to
 270  * a gate mpath.  The function also adds the Address Extension field and
 271  * updates the next hop.
 272  *
 273  * If a frame already has an Address Extension field, only the next hop and
 274  * destination addresses are updated.
 275  *
 276  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 277  *
 278  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 279  * @from_mpath: The failed mpath
 280  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 281  * move them.
 282  */
 283 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 284                                     struct mesh_path *from_mpath,
 285                                     bool copy)
 286 {
 287         struct sk_buff *skb, *fskb, *tmp;
 288         struct sk_buff_head failq;
 289         unsigned long flags;
 290
 291         if (WARN_ON(gate_mpath == from_mpath))
 292                 return;
 293         if (WARN_ON(!gate_mpath->next_hop))
 294                 return;
 295
 296         __skb_queue_head_init(&failq);
 297
 298         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 299         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 300         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 301
 302         skb_queue_walk_safe(&failq, fskb, tmp) {
 303                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 304                                   MESH_FRAME_QUEUE_LEN) {
 305                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 306                         break;
 307                 }
 308
 309                 skb = skb_copy(fskb, GFP_ATOMIC);
 310                 if (WARN_ON(!skb))
 311                         break;
 312
 313                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 314                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 315
 316                 if (copy)
 317                         continue;
 318
 319                 __skb_unlink(fskb, &failq);
 320                 kfree_skb(fskb);
 321         }
 322
 323         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 324                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 325
 326         if (!copy)
 327                 return;
 328
 329         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 330         skb_queue_splice(&failq, &from_mpath->frame_queue);
 331         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 332 }
 333
 334
 335 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 336                                       struct ieee80211_sub_if_data *sdata)
 337 {
 338         struct mesh_path *mpath;
 339         struct hlist_head *bucket;
 340         struct mpath_node *node;
 341
 342         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 343         hlist_for_each_entry_rcu(node, bucket, list) {
 344                 mpath = node->mpath;
 345                 if (mpath->sdata == sdata &&
 346                     ether_addr_equal(dst, mpath->dst)) {
 347                         if (mpath_expired(mpath)) {
 348                                 spin_lock_bh(&mpath->state_lock);
 349                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 350                                 spin_unlock_bh(&mpath->state_lock);
 351                         }
 352                         return mpath;
 353                 }
 354         }
 355         return NULL;
 356 }
 357
 358 /**
 359  * mesh_path_lookup - look up a path in the mesh path table
 360  * @sdata: local subif
 361  * @dst: hardware address (ETH_ALEN length) of destination
 362  *
 363  * Returns: pointer to the mesh path structure, or NULL if not found
 364  *
 365  * Locking: must be called within a read rcu section.
 366  */
 367 struct mesh_path *
 368 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 369 {
 370         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 371 }
 372
 373 struct mesh_path *
 374 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 375 {
 376         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 377 }
 378
 379
 380 /**
 381  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 382  * @idx: index
 383  * @sdata: local subif, or NULL for all entries
 384  *
 385  * Returns: pointer to the mesh path structure, or NULL if not found.
 386  *
 387  * Locking: must be called within a read rcu section.
 388  */
 389 struct mesh_path *
 390 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 391 {
 392         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 393         struct mpath_node *node;
 394         int i;
 395         int j = 0;
 396
 397         for_each_mesh_entry(tbl, node, i) {
 398                 if (sdata && node->mpath->sdata != sdata)
 399                         continue;
 400                 if (j++ == idx) {
 401                         if (mpath_expired(node->mpath)) {
 402                                 spin_lock_bh(&node->mpath->state_lock);
 403                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 404                                 spin_unlock_bh(&node->mpath->state_lock);
 405                         }
 406                         return node->mpath;
 407                 }
 408         }
 409
 410         return NULL;
 411 }
 412
 413 /**
 414  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 415  * @idx: index
 416  * @sdata: local subif, or NULL for all entries
 417  *
 418  * Returns: pointer to the proxy path structure, or NULL if not found.
 419  *
 420  * Locking: must be called within a read rcu section.
 421  */
 422 struct mesh_path *
 423 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 424 {
 425         struct mesh_table *tbl = rcu_dereference(mpp_paths);
 426         struct mpath_node *node;
 427         int i;
 428         int j = 0;
 429
 430         for_each_mesh_entry(tbl, node, i) {
 431                 if (sdata && node->mpath->sdata != sdata)
 432                         continue;
 433                 if (j++ == idx)
 434                         return node->mpath;
 435         }
 436
 437         return NULL;
 438 }
 439
 440 /**
 441  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 442  * @mpath: gate path to add to table
 443  */
 444 int mesh_path_add_gate(struct mesh_path *mpath)
 445 {
 446         struct mesh_table *tbl;
 447         struct mpath_node *gate, *new_gate;
 448         int err;
 449
 450         rcu_read_lock();
 451         tbl = rcu_dereference(mesh_paths);
 452
 453         hlist_for_each_entry_rcu(gate, tbl->known_gates, list)
 454                 if (gate->mpath == mpath) {
 455                         err = -EEXIST;
 456                         goto err_rcu;
 457                 }
 458
 459         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 460         if (!new_gate) {
 461                 err = -ENOMEM;
 462                 goto err_rcu;
 463         }
 464
 465         mpath->is_gate = true;
 466         mpath->sdata->u.mesh.num_gates++;
 467         new_gate->mpath = mpath;
 468         spin_lock_bh(&tbl->gates_lock);
 469         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 470         spin_unlock_bh(&tbl->gates_lock);
 471         mpath_dbg(mpath->sdata,
 472                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 473                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 474         err = 0;
 475 err_rcu:
 476         rcu_read_unlock();
 477         return err;
 478 }
 479
 480 /**
 481  * mesh_gate_del - remove a mesh gate from the list of known gates
 482  * @tbl: table which holds our list of known gates
 483  * @mpath: gate mpath
 484  *
 485  * Locking: must be called inside rcu_read_lock() section
 486  */
 487 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 488 {
 489         struct mpath_node *gate;
 490         struct hlist_node *q;
 491
 492         hlist_for_each_entry_safe(gate, q, tbl->known_gates, list) {
 493                 if (gate->mpath != mpath)
 494                         continue;
 495                 spin_lock_bh(&tbl->gates_lock);
 496                 hlist_del_rcu(&gate->list);
 497                 kfree_rcu(gate, rcu);
 498                 spin_unlock_bh(&tbl->gates_lock);
 499                 mpath->sdata->u.mesh.num_gates--;
 500                 mpath->is_gate = false;
 501                 mpath_dbg(mpath->sdata,
 502                           "Mesh path: Deleted gate: %pM. %d known gates\n",
 503                           mpath->dst, mpath->sdata->u.mesh.num_gates);
 504                 break;
 505         }
 506 }
 507
 508 /**
 509  * mesh_gate_num - number of gates known to this interface
 510  * @sdata: subif data
 511  */
 512 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 513 {
 514         return sdata->u.mesh.num_gates;
 515 }
 516
 517 /**
 518  * mesh_path_add - allocate and add a new path to the mesh path table
 519  * @dst: destination address of the path (ETH_ALEN length)
 520  * @sdata: local subif
 521  *
 522  * Returns: 0 on success
 523  *
 524  * State: the initial state of the new path is set to 0
 525  */
 526 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 527                                 const u8 *dst)
 528 {
 529         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 530         struct ieee80211_local *local = sdata->local;
 531         struct mesh_table *tbl;
 532         struct mesh_path *mpath, *new_mpath;
 533         struct mpath_node *node, *new_node;
 534         struct hlist_head *bucket;
 535         int grow = 0;
 536         int err;
 537         u32 hash_idx;
 538
 539         if (ether_addr_equal(dst, sdata->vif.addr))
 540                 /* never add ourselves as neighbours */
 541                 return ERR_PTR(-ENOTSUPP);
 542
 543         if (is_multicast_ether_addr(dst))
 544                 return ERR_PTR(-ENOTSUPP);
 545
 546         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 547                 return ERR_PTR(-ENOSPC);
 548
 549         read_lock_bh(&pathtbl_resize_lock);
 550         tbl = resize_dereference_mesh_paths();
 551
 552         hash_idx = mesh_table_hash(dst, sdata, tbl);
 553         bucket = &tbl->hash_buckets[hash_idx];
 554
 555         spin_lock(&tbl->hashwlock[hash_idx]);
 556
 557         hlist_for_each_entry(node, bucket, list) {
 558                 mpath = node->mpath;
 559                 if (mpath->sdata == sdata &&
 560                     ether_addr_equal(dst, mpath->dst))
 561                         goto found;
 562         }
 563
 564         err = -ENOMEM;
 565         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 566         if (!new_mpath)
 567                 goto err_path_alloc;
 568
 569         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 570         if (!new_node)
 571                 goto err_node_alloc;
 572
 573         memcpy(new_mpath->dst, dst, ETH_ALEN);
 574         eth_broadcast_addr(new_mpath->rann_snd_addr);
 575         new_mpath->is_root = false;
 576         new_mpath->sdata = sdata;
 577         new_mpath->flags = 0;
 578         skb_queue_head_init(&new_mpath->frame_queue);
 579         new_node->mpath = new_mpath;
 580         new_mpath->timer.data = (unsigned long) new_mpath;
 581         new_mpath->timer.function = mesh_path_timer;
 582         new_mpath->exp_time = jiffies;
 583         spin_lock_init(&new_mpath->state_lock);
 584         init_timer(&new_mpath->timer);
 585
 586         hlist_add_head_rcu(&new_node->list, bucket);
 587         if (atomic_inc_return(&tbl->entries) >=
 588             tbl->mean_chain_len * (tbl->hash_mask + 1))
 589                 grow = 1;
 590
 591         mesh_paths_generation++;
 592
 593         if (grow) {
 594                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 595                 ieee80211_queue_work(&local->hw, &sdata->work);
 596         }
 597         mpath = new_mpath;
 598 found:
 599         spin_unlock(&tbl->hashwlock[hash_idx]);
 600         read_unlock_bh(&pathtbl_resize_lock);
 601         return mpath;
 602
 603 err_node_alloc:
 604         kfree(new_mpath);
 605 err_path_alloc:
 606         atomic_dec(&sdata->u.mesh.mpaths);
 607         spin_unlock(&tbl->hashwlock[hash_idx]);
 608         read_unlock_bh(&pathtbl_resize_lock);
 609         return ERR_PTR(err);
 610 }
 611
 612 static void mesh_table_free_rcu(struct rcu_head *rcu)
 613 {
 614         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 615
 616         mesh_table_free(tbl, false);
 617 }
 618
 619 void mesh_mpath_table_grow(void)
 620 {
 621         struct mesh_table *oldtbl, *newtbl;
 622
 623         write_lock_bh(&pathtbl_resize_lock);
 624         oldtbl = resize_dereference_mesh_paths();
 625         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 626         if (!newtbl)
 627                 goto out;
 628         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 629                 __mesh_table_free(newtbl);
 630                 goto out;
 631         }
 632         rcu_assign_pointer(mesh_paths, newtbl);
 633
 634         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 635
 636  out:
 637         write_unlock_bh(&pathtbl_resize_lock);
 638 }
 639
 640 void mesh_mpp_table_grow(void)
 641 {
 642         struct mesh_table *oldtbl, *newtbl;
 643
 644         write_lock_bh(&pathtbl_resize_lock);
 645         oldtbl = resize_dereference_mpp_paths();
 646         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 647         if (!newtbl)
 648                 goto out;
 649         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 650                 __mesh_table_free(newtbl);
 651                 goto out;
 652         }
 653         rcu_assign_pointer(mpp_paths, newtbl);
 654         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 655
 656  out:
 657         write_unlock_bh(&pathtbl_resize_lock);
 658 }
 659
 660 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 661                  const u8 *dst, const u8 *mpp)
 662 {
 663         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 664         struct ieee80211_local *local = sdata->local;
 665         struct mesh_table *tbl;
 666         struct mesh_path *mpath, *new_mpath;
 667         struct mpath_node *node, *new_node;
 668         struct hlist_head *bucket;
 669         int grow = 0;
 670         int err = 0;
 671         u32 hash_idx;
 672
 673         if (ether_addr_equal(dst, sdata->vif.addr))
 674                 /* never add ourselves as neighbours */
 675                 return -ENOTSUPP;
 676
 677         if (is_multicast_ether_addr(dst))
 678                 return -ENOTSUPP;
 679
 680         err = -ENOMEM;
 681         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 682         if (!new_mpath)
 683                 goto err_path_alloc;
 684
 685         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 686         if (!new_node)
 687                 goto err_node_alloc;
 688
 689         read_lock_bh(&pathtbl_resize_lock);
 690         memcpy(new_mpath->dst, dst, ETH_ALEN);
 691         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 692         new_mpath->sdata = sdata;
 693         new_mpath->flags = 0;
 694         skb_queue_head_init(&new_mpath->frame_queue);
 695         new_node->mpath = new_mpath;
 696         init_timer(&new_mpath->timer);
 697         new_mpath->exp_time = jiffies;
 698         spin_lock_init(&new_mpath->state_lock);
 699
 700         tbl = resize_dereference_mpp_paths();
 701
 702         hash_idx = mesh_table_hash(dst, sdata, tbl);
 703         bucket = &tbl->hash_buckets[hash_idx];
 704
 705         spin_lock(&tbl->hashwlock[hash_idx]);
 706
 707         err = -EEXIST;
 708         hlist_for_each_entry(node, bucket, list) {
 709                 mpath = node->mpath;
 710                 if (mpath->sdata == sdata &&
 711                     ether_addr_equal(dst, mpath->dst))
 712                         goto err_exists;
 713         }
 714
 715         hlist_add_head_rcu(&new_node->list, bucket);
 716         if (atomic_inc_return(&tbl->entries) >=
 717             tbl->mean_chain_len * (tbl->hash_mask + 1))
 718                 grow = 1;
 719
 720         spin_unlock(&tbl->hashwlock[hash_idx]);
 721         read_unlock_bh(&pathtbl_resize_lock);
 722
 723         mpp_paths_generation++;
 724
 725         if (grow) {
 726                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 727                 ieee80211_queue_work(&local->hw, &sdata->work);
 728         }
 729         return 0;
 730
 731 err_exists:
 732         spin_unlock(&tbl->hashwlock[hash_idx]);
 733         read_unlock_bh(&pathtbl_resize_lock);
 734         kfree(new_node);
 735 err_node_alloc:
 736         kfree(new_mpath);
 737 err_path_alloc:
 738         return err;
 739 }
 740
 741
 742 /**
 743  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 744  *
 745  * @sta: broken peer link
 746  *
 747  * This function must be called from the rate control algorithm if enough
 748  * delivery errors suggest that a peer link is no longer usable.
 749  */
 750 void mesh_plink_broken(struct sta_info *sta)
 751 {
 752         struct mesh_table *tbl;
 753         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 754         struct mesh_path *mpath;
 755         struct mpath_node *node;
 756         struct ieee80211_sub_if_data *sdata = sta->sdata;
 757         int i;
 758
 759         rcu_read_lock();
 760         tbl = rcu_dereference(mesh_paths);
 761         for_each_mesh_entry(tbl, node, i) {
 762                 mpath = node->mpath;
 763                 if (rcu_access_pointer(mpath->next_hop) == sta &&
 764                     mpath->flags & MESH_PATH_ACTIVE &&
 765                     !(mpath->flags & MESH_PATH_FIXED)) {
 766                         spin_lock_bh(&mpath->state_lock);
 767                         mpath->flags &= ~MESH_PATH_ACTIVE;
 768                         ++mpath->sn;
 769                         spin_unlock_bh(&mpath->state_lock);
 770                         mesh_path_error_tx(sdata,
 771                                 sdata->u.mesh.mshcfg.element_ttl,
 772                                 mpath->dst, mpath->sn,
 773                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 774                 }
 775         }
 776         rcu_read_unlock();
 777 }
 778
 779 static void mesh_path_node_reclaim(struct rcu_head *rp)
 780 {
 781         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 782         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 783
 784         del_timer_sync(&node->mpath->timer);
 785         atomic_dec(&sdata->u.mesh.mpaths);
 786         kfree(node->mpath);
 787         kfree(node);
 788 }
 789
 790 /* needs to be called with the corresponding hashwlock taken */
 791 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 792 {
 793         struct mesh_path *mpath;
 794         mpath = node->mpath;
 795         spin_lock(&mpath->state_lock);
 796         mpath->flags |= MESH_PATH_RESOLVING;
 797         if (mpath->is_gate)
 798                 mesh_gate_del(tbl, mpath);
 799         hlist_del_rcu(&node->list);
 800         call_rcu(&node->rcu, mesh_path_node_reclaim);
 801         spin_unlock(&mpath->state_lock);
 802         atomic_dec(&tbl->entries);
 803 }
 804
 805 /**
 806  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 807  *
 808  * @sta: mesh peer to match
 809  *
 810  * RCU notes: this function is called when a mesh plink transitions from
 811  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 812  * allows path creation. This will happen before the sta can be freed (because
 813  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 814  * protected against the plink disappearing.
 815  */
 816 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 817 {
 818         struct mesh_table *tbl;
 819         struct mesh_path *mpath;
 820         struct mpath_node *node;
 821         int i;
 822
 823         rcu_read_lock();
 824         read_lock_bh(&pathtbl_resize_lock);
 825         tbl = resize_dereference_mesh_paths();
 826         for_each_mesh_entry(tbl, node, i) {
 827                 mpath = node->mpath;
 828                 if (rcu_access_pointer(mpath->next_hop) == sta) {
 829                         spin_lock(&tbl->hashwlock[i]);
 830                         __mesh_path_del(tbl, node);
 831                         spin_unlock(&tbl->hashwlock[i]);
 832                 }
 833         }
 834         read_unlock_bh(&pathtbl_resize_lock);
 835         rcu_read_unlock();
 836 }
 837
 838 static void table_flush_by_iface(struct mesh_table *tbl,
 839                                  struct ieee80211_sub_if_data *sdata)
 840 {
 841         struct mesh_path *mpath;
 842         struct mpath_node *node;
 843         int i;
 844
 845         WARN_ON(!rcu_read_lock_held());
 846         for_each_mesh_entry(tbl, node, i) {
 847                 mpath = node->mpath;
 848                 if (mpath->sdata != sdata)
 849                         continue;
 850                 spin_lock_bh(&tbl->hashwlock[i]);
 851                 __mesh_path_del(tbl, node);
 852                 spin_unlock_bh(&tbl->hashwlock[i]);
 853         }
 854 }
 855
 856 /**
 857  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 858  *
 859  * This function deletes both mesh paths as well as mesh portal paths.
 860  *
 861  * @sdata: interface data to match
 862  *
 863  */
 864 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 865 {
 866         struct mesh_table *tbl;
 867
 868         rcu_read_lock();
 869         read_lock_bh(&pathtbl_resize_lock);
 870         tbl = resize_dereference_mesh_paths();
 871         table_flush_by_iface(tbl, sdata);
 872         tbl = resize_dereference_mpp_paths();
 873         table_flush_by_iface(tbl, sdata);
 874         read_unlock_bh(&pathtbl_resize_lock);
 875         rcu_read_unlock();
 876 }
 877
 878 /**
 879  * mesh_path_del - delete a mesh path from the table
 880  *
 881  * @addr: dst address (ETH_ALEN length)
 882  * @sdata: local subif
 883  *
 884  * Returns: 0 if successful
 885  */
 886 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 887 {
 888         struct mesh_table *tbl;
 889         struct mesh_path *mpath;
 890         struct mpath_node *node;
 891         struct hlist_head *bucket;
 892         int hash_idx;
 893         int err = 0;
 894
 895         read_lock_bh(&pathtbl_resize_lock);
 896         tbl = resize_dereference_mesh_paths();
 897         hash_idx = mesh_table_hash(addr, sdata, tbl);
 898         bucket = &tbl->hash_buckets[hash_idx];
 899
 900         spin_lock(&tbl->hashwlock[hash_idx]);
 901         hlist_for_each_entry(node, bucket, list) {
 902                 mpath = node->mpath;
 903                 if (mpath->sdata == sdata &&
 904                     ether_addr_equal(addr, mpath->dst)) {
 905                         __mesh_path_del(tbl, node);
 906                         goto enddel;
 907                 }
 908         }
 909
 910         err = -ENXIO;
 911 enddel:
 912         mesh_paths_generation++;
 913         spin_unlock(&tbl->hashwlock[hash_idx]);
 914         read_unlock_bh(&pathtbl_resize_lock);
 915         return err;
 916 }
 917
 918 /**
 919  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 920  *
 921  * @mpath: mesh path to activate
 922  *
 923  * Locking: the state_lock of the mpath structure must NOT be held when calling
 924  * this function.
 925  */
 926 void mesh_path_tx_pending(struct mesh_path *mpath)
 927 {
 928         if (mpath->flags & MESH_PATH_ACTIVE)
 929                 ieee80211_add_pending_skbs(mpath->sdata->local,
 930                                 &mpath->frame_queue);
 931 }
 932
 933 /**
 934  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 935  *
 936  * @mpath: mesh path whose queue will be emptied
 937  *
 938  * If there is only one gate, the frames are transferred from the failed mpath
 939  * queue to that gate's queue.  If there are more than one gates, the frames
 940  * are copied from each gate to the next.  After frames are copied, the
 941  * mpath queues are emptied onto the transmission queue.
 942  */
 943 int mesh_path_send_to_gates(struct mesh_path *mpath)
 944 {
 945         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 946         struct mesh_table *tbl;
 947         struct mesh_path *from_mpath = mpath;
 948         struct mpath_node *gate = NULL;
 949         bool copy = false;
 950         struct hlist_head *known_gates;
 951
 952         rcu_read_lock();
 953         tbl = rcu_dereference(mesh_paths);
 954         known_gates = tbl->known_gates;
 955         rcu_read_unlock();
 956
 957         if (!known_gates)
 958                 return -EHOSTUNREACH;
 959
 960         hlist_for_each_entry_rcu(gate, known_gates, list) {
 961                 if (gate->mpath->sdata != sdata)
 962                         continue;
 963
 964                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 965                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 966                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 967                         from_mpath = gate->mpath;
 968                         copy = true;
 969                 } else {
 970                         mpath_dbg(sdata,
 971                                   "Not forwarding %p (flags %#x)\n",
 972                                   gate->mpath, gate->mpath->flags);
 973                 }
 974         }
 975
 976         hlist_for_each_entry_rcu(gate, known_gates, list)
 977                 if (gate->mpath->sdata == sdata) {
 978                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 979                         mesh_path_tx_pending(gate->mpath);
 980                 }
 981
 982         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 983 }
 984
 985 /**
 986  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 987  *
 988  * @skb: frame to discard
 989  * @sdata: network subif the frame was to be sent through
 990  *
 991  * Locking: the function must me called within a rcu_read_lock region
 992  */
 993 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 994                              struct sk_buff *skb)
 995 {
 996         kfree_skb(skb);
 997         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 998 }
 999
1000 /**
1001  * mesh_path_flush_pending - free the pending queue of a mesh path
1002  *
1003  * @mpath: mesh path whose queue has to be freed
1004  *
1005  * Locking: the function must me called within a rcu_read_lock region
1006  */
1007 void mesh_path_flush_pending(struct mesh_path *mpath)
1008 {
1009         struct sk_buff *skb;
1010
1011         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
1012                 mesh_path_discard_frame(mpath->sdata, skb);
1013 }
1014
1015 /**
1016  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1017  *
1018  * @mpath: the mesh path to modify
1019  * @next_hop: the next hop to force
1020  *
1021  * Locking: this function must be called holding mpath->state_lock
1022  */
1023 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1024 {
1025         spin_lock_bh(&mpath->state_lock);
1026         mesh_path_assign_nexthop(mpath, next_hop);
1027         mpath->sn = 0xffff;
1028         mpath->metric = 0;
1029         mpath->hop_count = 0;
1030         mpath->exp_time = 0;
1031         mpath->flags |= MESH_PATH_FIXED;
1032         mesh_path_activate(mpath);
1033         spin_unlock_bh(&mpath->state_lock);
1034         mesh_path_tx_pending(mpath);
1035 }
1036
1037 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1038 {
1039         struct mesh_path *mpath;
1040         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1041         mpath = node->mpath;
1042         hlist_del_rcu(p);
1043         if (free_leafs) {
1044                 del_timer_sync(&mpath->timer);
1045                 kfree(mpath);
1046         }
1047         kfree(node);
1048 }
1049
1050 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1051 {
1052         struct mesh_path *mpath;
1053         struct mpath_node *node, *new_node;
1054         u32 hash_idx;
1055
1056         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1057         if (new_node == NULL)
1058                 return -ENOMEM;
1059
1060         node = hlist_entry(p, struct mpath_node, list);
1061         mpath = node->mpath;
1062         new_node->mpath = mpath;
1063         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1064         hlist_add_head(&new_node->list,
1065                         &newtbl->hash_buckets[hash_idx]);
1066         return 0;
1067 }
1068
1069 int mesh_pathtbl_init(void)
1070 {
1071         struct mesh_table *tbl_path, *tbl_mpp;
1072         int ret;
1073
1074         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1075         if (!tbl_path)
1076                 return -ENOMEM;
1077         tbl_path->free_node = &mesh_path_node_free;
1078         tbl_path->copy_node = &mesh_path_node_copy;
1079         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1080         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1081         if (!tbl_path->known_gates) {
1082                 ret = -ENOMEM;
1083                 goto free_path;
1084         }
1085         INIT_HLIST_HEAD(tbl_path->known_gates);
1086
1087
1088         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1089         if (!tbl_mpp) {
1090                 ret = -ENOMEM;
1091                 goto free_path;
1092         }
1093         tbl_mpp->free_node = &mesh_path_node_free;
1094         tbl_mpp->copy_node = &mesh_path_node_copy;
1095         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1096         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1097         if (!tbl_mpp->known_gates) {
1098                 ret = -ENOMEM;
1099                 goto free_mpp;
1100         }
1101         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1102
1103         /* Need no locking since this is during init */
1104         RCU_INIT_POINTER(mesh_paths, tbl_path);
1105         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1106
1107         return 0;
1108
1109 free_mpp:
1110         mesh_table_free(tbl_mpp, true);
1111 free_path:
1112         mesh_table_free(tbl_path, true);
1113         return ret;
1114 }
1115
1116 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1117 {
1118         struct mesh_table *tbl;
1119         struct mesh_path *mpath;
1120         struct mpath_node *node;
1121         int i;
1122
1123         rcu_read_lock();
1124         tbl = rcu_dereference(mesh_paths);
1125         for_each_mesh_entry(tbl, node, i) {
1126                 if (node->mpath->sdata != sdata)
1127                         continue;
1128                 mpath = node->mpath;
1129                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1130                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1131                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1132                         mesh_path_del(mpath->sdata, mpath->dst);
1133         }
1134         rcu_read_unlock();
1135 }
1136
1137 void mesh_pathtbl_unregister(void)
1138 {
1139         /* no need for locking during exit path */
1140         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1141         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1142 }