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 #ifdef CONFIG_MAC80211_VERBOSE_MPATH_DEBUG
  22 #define mpath_dbg(fmt, args...) printk(KERN_DEBUG fmt, ##args)
  23 #else
  24 #define mpath_dbg(fmt, args...) do { (void)(0); } while (0)
  25 #endif
  26
  27 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  28 #define INIT_PATHS_SIZE_ORDER   2
  29
  30 /* Keep the mean chain length below this constant */
  31 #define MEAN_CHAIN_LEN          2
  32
  33 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  34                                 time_after(jiffies, mpath->exp_time) && \
  35                                 !(mpath->flags & MESH_PATH_FIXED))
  36
  37 struct mpath_node {
  38         struct hlist_node list;
  39         struct rcu_head rcu;
  40         /* This indirection allows two different tables to point to the same
  41          * mesh_path structure, useful when resizing
  42          */
  43         struct mesh_path *mpath;
  44 };
  45
  46 static struct mesh_table __rcu *mesh_paths;
  47 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  48
  49 int mesh_paths_generation;
  50
  51 /* This lock will have the grow table function as writer and add / delete nodes
  52  * as readers. RCU provides sufficient protection only when reading the table
  53  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  54  * the read lock or we risk operating on an old table.  The write lock is only
  55  * needed when modifying the number of buckets a table.
  56  */
  57 static DEFINE_RWLOCK(pathtbl_resize_lock);
  58
  59
  60 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  61 {
  62         return rcu_dereference_protected(mesh_paths,
  63                 lockdep_is_held(&pathtbl_resize_lock));
  64 }
  65
  66 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  67 {
  68         return rcu_dereference_protected(mpp_paths,
  69                 lockdep_is_held(&pathtbl_resize_lock));
  70 }
  71
  72 /*
  73  * CAREFUL -- "tbl" must not be an expression,
  74  * in particular not an rcu_dereference(), since
  75  * it's used twice. So it is illegal to do
  76  *      for_each_mesh_entry(rcu_dereference(...), ...)
  77  */
  78 #define for_each_mesh_entry(tbl, p, node, i) \
  79         for (i = 0; i <= tbl->hash_mask; i++) \
  80                 hlist_for_each_entry_rcu(node, p, &tbl->hash_buckets[i], list)
  81
  82
  83 static struct mesh_table *mesh_table_alloc(int size_order)
  84 {
  85         int i;
  86         struct mesh_table *newtbl;
  87
  88         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  89         if (!newtbl)
  90                 return NULL;
  91
  92         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  93                         (1 << size_order), GFP_ATOMIC);
  94
  95         if (!newtbl->hash_buckets) {
  96                 kfree(newtbl);
  97                 return NULL;
  98         }
  99
 100         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
 101                         (1 << size_order), GFP_ATOMIC);
 102         if (!newtbl->hashwlock) {
 103                 kfree(newtbl->hash_buckets);
 104                 kfree(newtbl);
 105                 return NULL;
 106         }
 107
 108         newtbl->size_order = size_order;
 109         newtbl->hash_mask = (1 << size_order) - 1;
 110         atomic_set(&newtbl->entries,  0);
 111         get_random_bytes(&newtbl->hash_rnd,
 112                         sizeof(newtbl->hash_rnd));
 113         for (i = 0; i <= newtbl->hash_mask; i++)
 114                 spin_lock_init(&newtbl->hashwlock[i]);
 115         spin_lock_init(&newtbl->gates_lock);
 116
 117         return newtbl;
 118 }
 119
 120 static void __mesh_table_free(struct mesh_table *tbl)
 121 {
 122         kfree(tbl->hash_buckets);
 123         kfree(tbl->hashwlock);
 124         kfree(tbl);
 125 }
 126
 127 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 128 {
 129         struct hlist_head *mesh_hash;
 130         struct hlist_node *p, *q;
 131         struct mpath_node *gate;
 132         int i;
 133
 134         mesh_hash = tbl->hash_buckets;
 135         for (i = 0; i <= tbl->hash_mask; i++) {
 136                 spin_lock_bh(&tbl->hashwlock[i]);
 137                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 138                         tbl->free_node(p, free_leafs);
 139                         atomic_dec(&tbl->entries);
 140                 }
 141                 spin_unlock_bh(&tbl->hashwlock[i]);
 142         }
 143         if (free_leafs) {
 144                 spin_lock_bh(&tbl->gates_lock);
 145                 hlist_for_each_entry_safe(gate, p, q,
 146                                          tbl->known_gates, list) {
 147                         hlist_del(&gate->list);
 148                         kfree(gate);
 149                 }
 150                 kfree(tbl->known_gates);
 151                 spin_unlock_bh(&tbl->gates_lock);
 152         }
 153
 154         __mesh_table_free(tbl);
 155 }
 156
 157 static int mesh_table_grow(struct mesh_table *oldtbl,
 158                            struct mesh_table *newtbl)
 159 {
 160         struct hlist_head *oldhash;
 161         struct hlist_node *p, *q;
 162         int i;
 163
 164         if (atomic_read(&oldtbl->entries)
 165                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 166                 return -EAGAIN;
 167
 168         newtbl->free_node = oldtbl->free_node;
 169         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 170         newtbl->copy_node = oldtbl->copy_node;
 171         newtbl->known_gates = oldtbl->known_gates;
 172         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 173
 174         oldhash = oldtbl->hash_buckets;
 175         for (i = 0; i <= oldtbl->hash_mask; i++)
 176                 hlist_for_each(p, &oldhash[i])
 177                         if (oldtbl->copy_node(p, newtbl) < 0)
 178                                 goto errcopy;
 179
 180         return 0;
 181
 182 errcopy:
 183         for (i = 0; i <= newtbl->hash_mask; i++) {
 184                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 185                         oldtbl->free_node(p, 0);
 186         }
 187         return -ENOMEM;
 188 }
 189
 190 static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
 191                            struct mesh_table *tbl)
 192 {
 193         /* Use last four bytes of hw addr and interface index as hash index */
 194         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
 195                 & tbl->hash_mask;
 196 }
 197
 198
 199 /**
 200  *
 201  * mesh_path_assign_nexthop - update mesh path next hop
 202  *
 203  * @mpath: mesh path to update
 204  * @sta: next hop to assign
 205  *
 206  * Locking: mpath->state_lock must be held when calling this function
 207  */
 208 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 209 {
 210         struct sk_buff *skb;
 211         struct ieee80211_hdr *hdr;
 212         struct sk_buff_head tmpq;
 213         unsigned long flags;
 214
 215         rcu_assign_pointer(mpath->next_hop, sta);
 216
 217         __skb_queue_head_init(&tmpq);
 218
 219         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 220
 221         while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
 222                 hdr = (struct ieee80211_hdr *) skb->data;
 223                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 224                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 225                 __skb_queue_tail(&tmpq, skb);
 226         }
 227
 228         skb_queue_splice(&tmpq, &mpath->frame_queue);
 229         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 230 }
 231
 232 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 233                              struct mesh_path *gate_mpath)
 234 {
 235         struct ieee80211_hdr *hdr;
 236         struct ieee80211s_hdr *mshdr;
 237         int mesh_hdrlen, hdrlen;
 238         char *next_hop;
 239
 240         hdr = (struct ieee80211_hdr *) skb->data;
 241         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 242         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 243
 244         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 245                 /* size of the fixed part of the mesh header */
 246                 mesh_hdrlen = 6;
 247
 248                 /* make room for the two extended addresses */
 249                 skb_push(skb, 2 * ETH_ALEN);
 250                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 251
 252                 hdr = (struct ieee80211_hdr *) skb->data;
 253
 254                 /* we preserve the previous mesh header and only add
 255                  * the new addreses */
 256                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 257                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 258                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 259                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 260         }
 261
 262         /* update next hop */
 263         hdr = (struct ieee80211_hdr *) skb->data;
 264         rcu_read_lock();
 265         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 266         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 267         rcu_read_unlock();
 268         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 269         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 270 }
 271
 272 /**
 273  *
 274  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 275  *
 276  * This function is used to transfer or copy frames from an unresolved mpath to
 277  * a gate mpath.  The function also adds the Address Extension field and
 278  * updates the next hop.
 279  *
 280  * If a frame already has an Address Extension field, only the next hop and
 281  * destination addresses are updated.
 282  *
 283  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 284  *
 285  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 286  * @from_mpath: The failed mpath
 287  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 288  * move them.
 289  */
 290 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 291                                     struct mesh_path *from_mpath,
 292                                     bool copy)
 293 {
 294         struct sk_buff *skb, *cp_skb = NULL;
 295         struct sk_buff_head gateq, failq;
 296         unsigned long flags;
 297         int num_skbs;
 298
 299         BUG_ON(gate_mpath == from_mpath);
 300         BUG_ON(!gate_mpath->next_hop);
 301
 302         __skb_queue_head_init(&gateq);
 303         __skb_queue_head_init(&failq);
 304
 305         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 306         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 307         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 308
 309         num_skbs = skb_queue_len(&failq);
 310
 311         while (num_skbs--) {
 312                 skb = __skb_dequeue(&failq);
 313                 if (copy) {
 314                         cp_skb = skb_copy(skb, GFP_ATOMIC);
 315                         if (cp_skb)
 316                                 __skb_queue_tail(&failq, cp_skb);
 317                 }
 318
 319                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 320                 __skb_queue_tail(&gateq, skb);
 321         }
 322
 323         spin_lock_irqsave(&gate_mpath->frame_queue.lock, flags);
 324         skb_queue_splice(&gateq, &gate_mpath->frame_queue);
 325         mpath_dbg("Mpath queue for gate %pM has %d frames\n",
 326                         gate_mpath->dst,
 327                         skb_queue_len(&gate_mpath->frame_queue));
 328         spin_unlock_irqrestore(&gate_mpath->frame_queue.lock, flags);
 329
 330         if (!copy)
 331                 return;
 332
 333         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 334         skb_queue_splice(&failq, &from_mpath->frame_queue);
 335         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 336 }
 337
 338
 339 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, u8 *dst,
 340                                           struct ieee80211_sub_if_data *sdata)
 341 {
 342         struct mesh_path *mpath;
 343         struct hlist_node *n;
 344         struct hlist_head *bucket;
 345         struct mpath_node *node;
 346
 347         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 348         hlist_for_each_entry_rcu(node, n, bucket, list) {
 349                 mpath = node->mpath;
 350                 if (mpath->sdata == sdata &&
 351                     ether_addr_equal(dst, mpath->dst)) {
 352                         if (MPATH_EXPIRED(mpath)) {
 353                                 spin_lock_bh(&mpath->state_lock);
 354                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 355                                 spin_unlock_bh(&mpath->state_lock);
 356                         }
 357                         return mpath;
 358                 }
 359         }
 360         return NULL;
 361 }
 362
 363 /**
 364  * mesh_path_lookup - look up a path in the mesh path table
 365  * @dst: hardware address (ETH_ALEN length) of destination
 366  * @sdata: local subif
 367  *
 368  * Returns: pointer to the mesh path structure, or NULL if not found
 369  *
 370  * Locking: must be called within a read rcu section.
 371  */
 372 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 373 {
 374         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 375 }
 376
 377 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 378 {
 379         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 380 }
 381
 382
 383 /**
 384  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 385  * @idx: index
 386  * @sdata: local subif, or NULL for all entries
 387  *
 388  * Returns: pointer to the mesh path structure, or NULL if not found.
 389  *
 390  * Locking: must be called within a read rcu section.
 391  */
 392 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 393 {
 394         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 395         struct mpath_node *node;
 396         struct hlist_node *p;
 397         int i;
 398         int j = 0;
 399
 400         for_each_mesh_entry(tbl, p, node, i) {
 401                 if (sdata && node->mpath->sdata != sdata)
 402                         continue;
 403                 if (j++ == idx) {
 404                         if (MPATH_EXPIRED(node->mpath)) {
 405                                 spin_lock_bh(&node->mpath->state_lock);
 406                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 407                                 spin_unlock_bh(&node->mpath->state_lock);
 408                         }
 409                         return node->mpath;
 410                 }
 411         }
 412
 413         return NULL;
 414 }
 415
 416 /**
 417  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 418  * @mpath: gate path to add to table
 419  */
 420 int mesh_path_add_gate(struct mesh_path *mpath)
 421 {
 422         struct mesh_table *tbl;
 423         struct mpath_node *gate, *new_gate;
 424         struct hlist_node *n;
 425         int err;
 426
 427         rcu_read_lock();
 428         tbl = rcu_dereference(mesh_paths);
 429
 430         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
 431                 if (gate->mpath == mpath) {
 432                         err = -EEXIST;
 433                         goto err_rcu;
 434                 }
 435
 436         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 437         if (!new_gate) {
 438                 err = -ENOMEM;
 439                 goto err_rcu;
 440         }
 441
 442         mpath->is_gate = true;
 443         mpath->sdata->u.mesh.num_gates++;
 444         new_gate->mpath = mpath;
 445         spin_lock_bh(&tbl->gates_lock);
 446         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 447         spin_unlock_bh(&tbl->gates_lock);
 448         rcu_read_unlock();
 449         mpath_dbg("Mesh path (%s): Recorded new gate: %pM. %d known gates\n",
 450                   mpath->sdata->name, mpath->dst,
 451                   mpath->sdata->u.mesh.num_gates);
 452         return 0;
 453 err_rcu:
 454         rcu_read_unlock();
 455         return err;
 456 }
 457
 458 /**
 459  * mesh_gate_del - remove a mesh gate from the list of known gates
 460  * @tbl: table which holds our list of known gates
 461  * @mpath: gate mpath
 462  *
 463  * Returns: 0 on success
 464  *
 465  * Locking: must be called inside rcu_read_lock() section
 466  */
 467 static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 468 {
 469         struct mpath_node *gate;
 470         struct hlist_node *p, *q;
 471
 472         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list)
 473                 if (gate->mpath == mpath) {
 474                         spin_lock_bh(&tbl->gates_lock);
 475                         hlist_del_rcu(&gate->list);
 476                         kfree_rcu(gate, rcu);
 477                         spin_unlock_bh(&tbl->gates_lock);
 478                         mpath->sdata->u.mesh.num_gates--;
 479                         mpath->is_gate = false;
 480                         mpath_dbg("Mesh path (%s): Deleted gate: %pM. "
 481                                   "%d known gates\n", mpath->sdata->name,
 482                                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 483                         break;
 484                 }
 485
 486         return 0;
 487 }
 488
 489 /**
 490  * mesh_gate_num - number of gates known to this interface
 491  * @sdata: subif data
 492  */
 493 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 494 {
 495         return sdata->u.mesh.num_gates;
 496 }
 497
 498 /**
 499  * mesh_path_add - allocate and add a new path to the mesh path table
 500  * @addr: destination address of the path (ETH_ALEN length)
 501  * @sdata: local subif
 502  *
 503  * Returns: 0 on success
 504  *
 505  * State: the initial state of the new path is set to 0
 506  */
 507 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 508 {
 509         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 510         struct ieee80211_local *local = sdata->local;
 511         struct mesh_table *tbl;
 512         struct mesh_path *mpath, *new_mpath;
 513         struct mpath_node *node, *new_node;
 514         struct hlist_head *bucket;
 515         struct hlist_node *n;
 516         int grow = 0;
 517         int err = 0;
 518         u32 hash_idx;
 519
 520         if (ether_addr_equal(dst, sdata->vif.addr))
 521                 /* never add ourselves as neighbours */
 522                 return -ENOTSUPP;
 523
 524         if (is_multicast_ether_addr(dst))
 525                 return -ENOTSUPP;
 526
 527         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 528                 return -ENOSPC;
 529
 530         err = -ENOMEM;
 531         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 532         if (!new_mpath)
 533                 goto err_path_alloc;
 534
 535         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 536         if (!new_node)
 537                 goto err_node_alloc;
 538
 539         read_lock_bh(&pathtbl_resize_lock);
 540         memcpy(new_mpath->dst, dst, ETH_ALEN);
 541         memset(new_mpath->rann_snd_addr, 0xff, ETH_ALEN);
 542         new_mpath->is_root = false;
 543         new_mpath->sdata = sdata;
 544         new_mpath->flags = 0;
 545         skb_queue_head_init(&new_mpath->frame_queue);
 546         new_node->mpath = new_mpath;
 547         new_mpath->timer.data = (unsigned long) new_mpath;
 548         new_mpath->timer.function = mesh_path_timer;
 549         new_mpath->exp_time = jiffies;
 550         spin_lock_init(&new_mpath->state_lock);
 551         init_timer(&new_mpath->timer);
 552
 553         tbl = resize_dereference_mesh_paths();
 554
 555         hash_idx = mesh_table_hash(dst, sdata, tbl);
 556         bucket = &tbl->hash_buckets[hash_idx];
 557
 558         spin_lock(&tbl->hashwlock[hash_idx]);
 559
 560         err = -EEXIST;
 561         hlist_for_each_entry(node, n, bucket, list) {
 562                 mpath = node->mpath;
 563                 if (mpath->sdata == sdata &&
 564                     ether_addr_equal(dst, mpath->dst))
 565                         goto err_exists;
 566         }
 567
 568         hlist_add_head_rcu(&new_node->list, bucket);
 569         if (atomic_inc_return(&tbl->entries) >=
 570             tbl->mean_chain_len * (tbl->hash_mask + 1))
 571                 grow = 1;
 572
 573         mesh_paths_generation++;
 574
 575         spin_unlock(&tbl->hashwlock[hash_idx]);
 576         read_unlock_bh(&pathtbl_resize_lock);
 577         if (grow) {
 578                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 579                 ieee80211_queue_work(&local->hw, &sdata->work);
 580         }
 581         return 0;
 582
 583 err_exists:
 584         spin_unlock(&tbl->hashwlock[hash_idx]);
 585         read_unlock_bh(&pathtbl_resize_lock);
 586         kfree(new_node);
 587 err_node_alloc:
 588         kfree(new_mpath);
 589 err_path_alloc:
 590         atomic_dec(&sdata->u.mesh.mpaths);
 591         return err;
 592 }
 593
 594 static void mesh_table_free_rcu(struct rcu_head *rcu)
 595 {
 596         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 597
 598         mesh_table_free(tbl, false);
 599 }
 600
 601 void mesh_mpath_table_grow(void)
 602 {
 603         struct mesh_table *oldtbl, *newtbl;
 604
 605         write_lock_bh(&pathtbl_resize_lock);
 606         oldtbl = resize_dereference_mesh_paths();
 607         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 608         if (!newtbl)
 609                 goto out;
 610         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 611                 __mesh_table_free(newtbl);
 612                 goto out;
 613         }
 614         rcu_assign_pointer(mesh_paths, newtbl);
 615
 616         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 617
 618  out:
 619         write_unlock_bh(&pathtbl_resize_lock);
 620 }
 621
 622 void mesh_mpp_table_grow(void)
 623 {
 624         struct mesh_table *oldtbl, *newtbl;
 625
 626         write_lock_bh(&pathtbl_resize_lock);
 627         oldtbl = resize_dereference_mpp_paths();
 628         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 629         if (!newtbl)
 630                 goto out;
 631         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 632                 __mesh_table_free(newtbl);
 633                 goto out;
 634         }
 635         rcu_assign_pointer(mpp_paths, newtbl);
 636         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 637
 638  out:
 639         write_unlock_bh(&pathtbl_resize_lock);
 640 }
 641
 642 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 643 {
 644         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 645         struct ieee80211_local *local = sdata->local;
 646         struct mesh_table *tbl;
 647         struct mesh_path *mpath, *new_mpath;
 648         struct mpath_node *node, *new_node;
 649         struct hlist_head *bucket;
 650         struct hlist_node *n;
 651         int grow = 0;
 652         int err = 0;
 653         u32 hash_idx;
 654
 655         if (ether_addr_equal(dst, sdata->vif.addr))
 656                 /* never add ourselves as neighbours */
 657                 return -ENOTSUPP;
 658
 659         if (is_multicast_ether_addr(dst))
 660                 return -ENOTSUPP;
 661
 662         err = -ENOMEM;
 663         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 664         if (!new_mpath)
 665                 goto err_path_alloc;
 666
 667         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 668         if (!new_node)
 669                 goto err_node_alloc;
 670
 671         read_lock_bh(&pathtbl_resize_lock);
 672         memcpy(new_mpath->dst, dst, ETH_ALEN);
 673         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 674         new_mpath->sdata = sdata;
 675         new_mpath->flags = 0;
 676         skb_queue_head_init(&new_mpath->frame_queue);
 677         new_node->mpath = new_mpath;
 678         init_timer(&new_mpath->timer);
 679         new_mpath->exp_time = jiffies;
 680         spin_lock_init(&new_mpath->state_lock);
 681
 682         tbl = resize_dereference_mpp_paths();
 683
 684         hash_idx = mesh_table_hash(dst, sdata, tbl);
 685         bucket = &tbl->hash_buckets[hash_idx];
 686
 687         spin_lock(&tbl->hashwlock[hash_idx]);
 688
 689         err = -EEXIST;
 690         hlist_for_each_entry(node, n, bucket, list) {
 691                 mpath = node->mpath;
 692                 if (mpath->sdata == sdata &&
 693                     ether_addr_equal(dst, mpath->dst))
 694                         goto err_exists;
 695         }
 696
 697         hlist_add_head_rcu(&new_node->list, bucket);
 698         if (atomic_inc_return(&tbl->entries) >=
 699             tbl->mean_chain_len * (tbl->hash_mask + 1))
 700                 grow = 1;
 701
 702         spin_unlock(&tbl->hashwlock[hash_idx]);
 703         read_unlock_bh(&pathtbl_resize_lock);
 704         if (grow) {
 705                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 706                 ieee80211_queue_work(&local->hw, &sdata->work);
 707         }
 708         return 0;
 709
 710 err_exists:
 711         spin_unlock(&tbl->hashwlock[hash_idx]);
 712         read_unlock_bh(&pathtbl_resize_lock);
 713         kfree(new_node);
 714 err_node_alloc:
 715         kfree(new_mpath);
 716 err_path_alloc:
 717         return err;
 718 }
 719
 720
 721 /**
 722  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 723  *
 724  * @sta: broken peer link
 725  *
 726  * This function must be called from the rate control algorithm if enough
 727  * delivery errors suggest that a peer link is no longer usable.
 728  */
 729 void mesh_plink_broken(struct sta_info *sta)
 730 {
 731         struct mesh_table *tbl;
 732         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 733         struct mesh_path *mpath;
 734         struct mpath_node *node;
 735         struct hlist_node *p;
 736         struct ieee80211_sub_if_data *sdata = sta->sdata;
 737         int i;
 738         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 739
 740         rcu_read_lock();
 741         tbl = rcu_dereference(mesh_paths);
 742         for_each_mesh_entry(tbl, p, node, i) {
 743                 mpath = node->mpath;
 744                 if (rcu_dereference(mpath->next_hop) == sta &&
 745                     mpath->flags & MESH_PATH_ACTIVE &&
 746                     !(mpath->flags & MESH_PATH_FIXED)) {
 747                         spin_lock_bh(&mpath->state_lock);
 748                         mpath->flags &= ~MESH_PATH_ACTIVE;
 749                         ++mpath->sn;
 750                         spin_unlock_bh(&mpath->state_lock);
 751                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 752                                         mpath->dst, cpu_to_le32(mpath->sn),
 753                                         reason, bcast, sdata);
 754                 }
 755         }
 756         rcu_read_unlock();
 757 }
 758
 759 static void mesh_path_node_reclaim(struct rcu_head *rp)
 760 {
 761         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 762         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 763
 764         del_timer_sync(&node->mpath->timer);
 765         atomic_dec(&sdata->u.mesh.mpaths);
 766         kfree(node->mpath);
 767         kfree(node);
 768 }
 769
 770 /* needs to be called with the corresponding hashwlock taken */
 771 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 772 {
 773         struct mesh_path *mpath;
 774         mpath = node->mpath;
 775         spin_lock(&mpath->state_lock);
 776         mpath->flags |= MESH_PATH_RESOLVING;
 777         if (mpath->is_gate)
 778                 mesh_gate_del(tbl, mpath);
 779         hlist_del_rcu(&node->list);
 780         call_rcu(&node->rcu, mesh_path_node_reclaim);
 781         spin_unlock(&mpath->state_lock);
 782         atomic_dec(&tbl->entries);
 783 }
 784
 785 /**
 786  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 787  *
 788  * @sta - mesh peer to match
 789  *
 790  * RCU notes: this function is called when a mesh plink transitions from
 791  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 792  * allows path creation. This will happen before the sta can be freed (because
 793  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 794  * protected against the plink disappearing.
 795  */
 796 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 797 {
 798         struct mesh_table *tbl;
 799         struct mesh_path *mpath;
 800         struct mpath_node *node;
 801         struct hlist_node *p;
 802         int i;
 803
 804         rcu_read_lock();
 805         read_lock_bh(&pathtbl_resize_lock);
 806         tbl = resize_dereference_mesh_paths();
 807         for_each_mesh_entry(tbl, p, node, i) {
 808                 mpath = node->mpath;
 809                 if (rcu_dereference(mpath->next_hop) == sta) {
 810                         spin_lock(&tbl->hashwlock[i]);
 811                         __mesh_path_del(tbl, node);
 812                         spin_unlock(&tbl->hashwlock[i]);
 813                 }
 814         }
 815         read_unlock_bh(&pathtbl_resize_lock);
 816         rcu_read_unlock();
 817 }
 818
 819 static void table_flush_by_iface(struct mesh_table *tbl,
 820                                  struct ieee80211_sub_if_data *sdata)
 821 {
 822         struct mesh_path *mpath;
 823         struct mpath_node *node;
 824         struct hlist_node *p;
 825         int i;
 826
 827         WARN_ON(!rcu_read_lock_held());
 828         for_each_mesh_entry(tbl, p, node, i) {
 829                 mpath = node->mpath;
 830                 if (mpath->sdata != sdata)
 831                         continue;
 832                 spin_lock_bh(&tbl->hashwlock[i]);
 833                 __mesh_path_del(tbl, node);
 834                 spin_unlock_bh(&tbl->hashwlock[i]);
 835         }
 836 }
 837
 838 /**
 839  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 840  *
 841  * This function deletes both mesh paths as well as mesh portal paths.
 842  *
 843  * @sdata - interface data to match
 844  *
 845  */
 846 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 847 {
 848         struct mesh_table *tbl;
 849
 850         rcu_read_lock();
 851         read_lock_bh(&pathtbl_resize_lock);
 852         tbl = resize_dereference_mesh_paths();
 853         table_flush_by_iface(tbl, sdata);
 854         tbl = resize_dereference_mpp_paths();
 855         table_flush_by_iface(tbl, sdata);
 856         read_unlock_bh(&pathtbl_resize_lock);
 857         rcu_read_unlock();
 858 }
 859
 860 /**
 861  * mesh_path_del - delete a mesh path from the table
 862  *
 863  * @addr: dst address (ETH_ALEN length)
 864  * @sdata: local subif
 865  *
 866  * Returns: 0 if successful
 867  */
 868 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 869 {
 870         struct mesh_table *tbl;
 871         struct mesh_path *mpath;
 872         struct mpath_node *node;
 873         struct hlist_head *bucket;
 874         struct hlist_node *n;
 875         int hash_idx;
 876         int err = 0;
 877
 878         read_lock_bh(&pathtbl_resize_lock);
 879         tbl = resize_dereference_mesh_paths();
 880         hash_idx = mesh_table_hash(addr, sdata, tbl);
 881         bucket = &tbl->hash_buckets[hash_idx];
 882
 883         spin_lock(&tbl->hashwlock[hash_idx]);
 884         hlist_for_each_entry(node, n, bucket, list) {
 885                 mpath = node->mpath;
 886                 if (mpath->sdata == sdata &&
 887                     ether_addr_equal(addr, mpath->dst)) {
 888                         __mesh_path_del(tbl, node);
 889                         goto enddel;
 890                 }
 891         }
 892
 893         err = -ENXIO;
 894 enddel:
 895         mesh_paths_generation++;
 896         spin_unlock(&tbl->hashwlock[hash_idx]);
 897         read_unlock_bh(&pathtbl_resize_lock);
 898         return err;
 899 }
 900
 901 /**
 902  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 903  *
 904  * @mpath: mesh path to activate
 905  *
 906  * Locking: the state_lock of the mpath structure must NOT be held when calling
 907  * this function.
 908  */
 909 void mesh_path_tx_pending(struct mesh_path *mpath)
 910 {
 911         if (mpath->flags & MESH_PATH_ACTIVE)
 912                 ieee80211_add_pending_skbs(mpath->sdata->local,
 913                                 &mpath->frame_queue);
 914 }
 915
 916 /**
 917  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 918  *
 919  * @mpath: mesh path whose queue will be emptied
 920  *
 921  * If there is only one gate, the frames are transferred from the failed mpath
 922  * queue to that gate's queue.  If there are more than one gates, the frames
 923  * are copied from each gate to the next.  After frames are copied, the
 924  * mpath queues are emptied onto the transmission queue.
 925  */
 926 int mesh_path_send_to_gates(struct mesh_path *mpath)
 927 {
 928         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 929         struct hlist_node *n;
 930         struct mesh_table *tbl;
 931         struct mesh_path *from_mpath = mpath;
 932         struct mpath_node *gate = NULL;
 933         bool copy = false;
 934         struct hlist_head *known_gates;
 935
 936         rcu_read_lock();
 937         tbl = rcu_dereference(mesh_paths);
 938         known_gates = tbl->known_gates;
 939         rcu_read_unlock();
 940
 941         if (!known_gates)
 942                 return -EHOSTUNREACH;
 943
 944         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
 945                 if (gate->mpath->sdata != sdata)
 946                         continue;
 947
 948                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 949                         mpath_dbg("Forwarding to %pM\n", gate->mpath->dst);
 950                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 951                         from_mpath = gate->mpath;
 952                         copy = true;
 953                 } else {
 954                         mpath_dbg("Not forwarding %p\n", gate->mpath);
 955                         mpath_dbg("flags %x\n", gate->mpath->flags);
 956                 }
 957         }
 958
 959         hlist_for_each_entry_rcu(gate, n, known_gates, list)
 960                 if (gate->mpath->sdata == sdata) {
 961                         mpath_dbg("Sending to %pM\n", gate->mpath->dst);
 962                         mesh_path_tx_pending(gate->mpath);
 963                 }
 964
 965         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 966 }
 967
 968 /**
 969  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 970  *
 971  * @skb: frame to discard
 972  * @sdata: network subif the frame was to be sent through
 973  *
 974  * Locking: the function must me called within a rcu_read_lock region
 975  */
 976 void mesh_path_discard_frame(struct sk_buff *skb,
 977                              struct ieee80211_sub_if_data *sdata)
 978 {
 979         kfree_skb(skb);
 980         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 981 }
 982
 983 /**
 984  * mesh_path_flush_pending - free the pending queue of a mesh path
 985  *
 986  * @mpath: mesh path whose queue has to be freed
 987  *
 988  * Locking: the function must me called within a rcu_read_lock region
 989  */
 990 void mesh_path_flush_pending(struct mesh_path *mpath)
 991 {
 992         struct sk_buff *skb;
 993
 994         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 995                 mesh_path_discard_frame(skb, mpath->sdata);
 996 }
 997
 998 /**
 999  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1000  *
1001  * @mpath: the mesh path to modify
1002  * @next_hop: the next hop to force
1003  *
1004  * Locking: this function must be called holding mpath->state_lock
1005  */
1006 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1007 {
1008         spin_lock_bh(&mpath->state_lock);
1009         mesh_path_assign_nexthop(mpath, next_hop);
1010         mpath->sn = 0xffff;
1011         mpath->metric = 0;
1012         mpath->hop_count = 0;
1013         mpath->exp_time = 0;
1014         mpath->flags |= MESH_PATH_FIXED;
1015         mesh_path_activate(mpath);
1016         spin_unlock_bh(&mpath->state_lock);
1017         mesh_path_tx_pending(mpath);
1018 }
1019
1020 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1021 {
1022         struct mesh_path *mpath;
1023         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1024         mpath = node->mpath;
1025         hlist_del_rcu(p);
1026         if (free_leafs) {
1027                 del_timer_sync(&mpath->timer);
1028                 kfree(mpath);
1029         }
1030         kfree(node);
1031 }
1032
1033 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1034 {
1035         struct mesh_path *mpath;
1036         struct mpath_node *node, *new_node;
1037         u32 hash_idx;
1038
1039         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1040         if (new_node == NULL)
1041                 return -ENOMEM;
1042
1043         node = hlist_entry(p, struct mpath_node, list);
1044         mpath = node->mpath;
1045         new_node->mpath = mpath;
1046         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1047         hlist_add_head(&new_node->list,
1048                         &newtbl->hash_buckets[hash_idx]);
1049         return 0;
1050 }
1051
1052 int mesh_pathtbl_init(void)
1053 {
1054         struct mesh_table *tbl_path, *tbl_mpp;
1055         int ret;
1056
1057         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1058         if (!tbl_path)
1059                 return -ENOMEM;
1060         tbl_path->free_node = &mesh_path_node_free;
1061         tbl_path->copy_node = &mesh_path_node_copy;
1062         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1063         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1064         if (!tbl_path->known_gates) {
1065                 ret = -ENOMEM;
1066                 goto free_path;
1067         }
1068         INIT_HLIST_HEAD(tbl_path->known_gates);
1069
1070
1071         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1072         if (!tbl_mpp) {
1073                 ret = -ENOMEM;
1074                 goto free_path;
1075         }
1076         tbl_mpp->free_node = &mesh_path_node_free;
1077         tbl_mpp->copy_node = &mesh_path_node_copy;
1078         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1079         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1080         if (!tbl_mpp->known_gates) {
1081                 ret = -ENOMEM;
1082                 goto free_mpp;
1083         }
1084         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1085
1086         /* Need no locking since this is during init */
1087         RCU_INIT_POINTER(mesh_paths, tbl_path);
1088         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1089
1090         return 0;
1091
1092 free_mpp:
1093         mesh_table_free(tbl_mpp, true);
1094 free_path:
1095         mesh_table_free(tbl_path, true);
1096         return ret;
1097 }
1098
1099 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1100 {
1101         struct mesh_table *tbl;
1102         struct mesh_path *mpath;
1103         struct mpath_node *node;
1104         struct hlist_node *p;
1105         int i;
1106
1107         rcu_read_lock();
1108         tbl = rcu_dereference(mesh_paths);
1109         for_each_mesh_entry(tbl, p, node, i) {
1110                 if (node->mpath->sdata != sdata)
1111                         continue;
1112                 mpath = node->mpath;
1113                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1114                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1115                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1116                         mesh_path_del(mpath->dst, mpath->sdata);
1117         }
1118         rcu_read_unlock();
1119 }
1120
1121 void mesh_pathtbl_unregister(void)
1122 {
1123         /* no need for locking during exit path */
1124         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1125         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1126 }