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 *path_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                                 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 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 path_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 path_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 static void mesh_gate_node_reclaim(struct rcu_head *rp)
 417 {
 418         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 419         kfree(node);
 420 }
 421
 422 /**
 423  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 424  * @mpath: gate path to add to table
 425  */
 426 int mesh_path_add_gate(struct mesh_path *mpath)
 427 {
 428         struct mesh_table *tbl;
 429         struct mpath_node *gate, *new_gate;
 430         struct hlist_node *n;
 431         int err;
 432
 433         rcu_read_lock();
 434         tbl = rcu_dereference(mesh_paths);
 435
 436         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
 437                 if (gate->mpath == mpath) {
 438                         err = -EEXIST;
 439                         goto err_rcu;
 440                 }
 441
 442         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 443         if (!new_gate) {
 444                 err = -ENOMEM;
 445                 goto err_rcu;
 446         }
 447
 448         mpath->is_gate = true;
 449         mpath->sdata->u.mesh.num_gates++;
 450         new_gate->mpath = mpath;
 451         spin_lock_bh(&tbl->gates_lock);
 452         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 453         spin_unlock_bh(&tbl->gates_lock);
 454         rcu_read_unlock();
 455         mpath_dbg("Mesh path (%s): Recorded new gate: %pM. %d known gates\n",
 456                   mpath->sdata->name, mpath->dst,
 457                   mpath->sdata->u.mesh.num_gates);
 458         return 0;
 459 err_rcu:
 460         rcu_read_unlock();
 461         return err;
 462 }
 463
 464 /**
 465  * mesh_gate_del - remove a mesh gate from the list of known gates
 466  * @tbl: table which holds our list of known gates
 467  * @mpath: gate mpath
 468  *
 469  * Returns: 0 on success
 470  *
 471  * Locking: must be called inside rcu_read_lock() section
 472  */
 473 static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 474 {
 475         struct mpath_node *gate;
 476         struct hlist_node *p, *q;
 477
 478         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list)
 479                 if (gate->mpath == mpath) {
 480                         spin_lock_bh(&tbl->gates_lock);
 481                         hlist_del_rcu(&gate->list);
 482                         call_rcu(&gate->rcu, mesh_gate_node_reclaim);
 483                         spin_unlock_bh(&tbl->gates_lock);
 484                         mpath->sdata->u.mesh.num_gates--;
 485                         mpath->is_gate = false;
 486                         mpath_dbg("Mesh path (%s): Deleted gate: %pM. "
 487                                   "%d known gates\n", mpath->sdata->name,
 488                                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 489                         break;
 490                 }
 491
 492         return 0;
 493 }
 494
 495 /**
 496  * mesh_gate_num - number of gates known to this interface
 497  * @sdata: subif data
 498  */
 499 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 500 {
 501         return sdata->u.mesh.num_gates;
 502 }
 503
 504 /**
 505  * mesh_path_add - allocate and add a new path to the mesh path table
 506  * @addr: destination address of the path (ETH_ALEN length)
 507  * @sdata: local subif
 508  *
 509  * Returns: 0 on success
 510  *
 511  * State: the initial state of the new path is set to 0
 512  */
 513 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 514 {
 515         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 516         struct ieee80211_local *local = sdata->local;
 517         struct mesh_table *tbl;
 518         struct mesh_path *mpath, *new_mpath;
 519         struct mpath_node *node, *new_node;
 520         struct hlist_head *bucket;
 521         struct hlist_node *n;
 522         int grow = 0;
 523         int err = 0;
 524         u32 hash_idx;
 525
 526         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 527                 /* never add ourselves as neighbours */
 528                 return -ENOTSUPP;
 529
 530         if (is_multicast_ether_addr(dst))
 531                 return -ENOTSUPP;
 532
 533         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 534                 return -ENOSPC;
 535
 536         err = -ENOMEM;
 537         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 538         if (!new_mpath)
 539                 goto err_path_alloc;
 540
 541         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 542         if (!new_node)
 543                 goto err_node_alloc;
 544
 545         read_lock_bh(&pathtbl_resize_lock);
 546         memcpy(new_mpath->dst, dst, ETH_ALEN);
 547         new_mpath->sdata = sdata;
 548         new_mpath->flags = 0;
 549         skb_queue_head_init(&new_mpath->frame_queue);
 550         new_node->mpath = new_mpath;
 551         new_mpath->timer.data = (unsigned long) new_mpath;
 552         new_mpath->timer.function = mesh_path_timer;
 553         new_mpath->exp_time = jiffies;
 554         spin_lock_init(&new_mpath->state_lock);
 555         init_timer(&new_mpath->timer);
 556
 557         tbl = resize_dereference_mesh_paths();
 558
 559         hash_idx = mesh_table_hash(dst, sdata, tbl);
 560         bucket = &tbl->hash_buckets[hash_idx];
 561
 562         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 563
 564         err = -EEXIST;
 565         hlist_for_each_entry(node, n, bucket, list) {
 566                 mpath = node->mpath;
 567                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 568                         goto err_exists;
 569         }
 570
 571         hlist_add_head_rcu(&new_node->list, bucket);
 572         if (atomic_inc_return(&tbl->entries) >=
 573             tbl->mean_chain_len * (tbl->hash_mask + 1))
 574                 grow = 1;
 575
 576         mesh_paths_generation++;
 577
 578         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 579         read_unlock_bh(&pathtbl_resize_lock);
 580         if (grow) {
 581                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 582                 ieee80211_queue_work(&local->hw, &sdata->work);
 583         }
 584         return 0;
 585
 586 err_exists:
 587         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 588         read_unlock_bh(&pathtbl_resize_lock);
 589         kfree(new_node);
 590 err_node_alloc:
 591         kfree(new_mpath);
 592 err_path_alloc:
 593         atomic_dec(&sdata->u.mesh.mpaths);
 594         return err;
 595 }
 596
 597 static void mesh_table_free_rcu(struct rcu_head *rcu)
 598 {
 599         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 600
 601         mesh_table_free(tbl, false);
 602 }
 603
 604 void mesh_mpath_table_grow(void)
 605 {
 606         struct mesh_table *oldtbl, *newtbl;
 607
 608         write_lock_bh(&pathtbl_resize_lock);
 609         oldtbl = resize_dereference_mesh_paths();
 610         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 611         if (!newtbl)
 612                 goto out;
 613         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 614                 __mesh_table_free(newtbl);
 615                 goto out;
 616         }
 617         rcu_assign_pointer(mesh_paths, newtbl);
 618
 619         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 620
 621  out:
 622         write_unlock_bh(&pathtbl_resize_lock);
 623 }
 624
 625 void mesh_mpp_table_grow(void)
 626 {
 627         struct mesh_table *oldtbl, *newtbl;
 628
 629         write_lock_bh(&pathtbl_resize_lock);
 630         oldtbl = resize_dereference_mpp_paths();
 631         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 632         if (!newtbl)
 633                 goto out;
 634         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 635                 __mesh_table_free(newtbl);
 636                 goto out;
 637         }
 638         rcu_assign_pointer(mpp_paths, newtbl);
 639         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 640
 641  out:
 642         write_unlock_bh(&pathtbl_resize_lock);
 643 }
 644
 645 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 646 {
 647         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 648         struct ieee80211_local *local = sdata->local;
 649         struct mesh_table *tbl;
 650         struct mesh_path *mpath, *new_mpath;
 651         struct mpath_node *node, *new_node;
 652         struct hlist_head *bucket;
 653         struct hlist_node *n;
 654         int grow = 0;
 655         int err = 0;
 656         u32 hash_idx;
 657
 658         if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
 659                 /* never add ourselves as neighbours */
 660                 return -ENOTSUPP;
 661
 662         if (is_multicast_ether_addr(dst))
 663                 return -ENOTSUPP;
 664
 665         err = -ENOMEM;
 666         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 667         if (!new_mpath)
 668                 goto err_path_alloc;
 669
 670         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 671         if (!new_node)
 672                 goto err_node_alloc;
 673
 674         read_lock_bh(&pathtbl_resize_lock);
 675         memcpy(new_mpath->dst, dst, ETH_ALEN);
 676         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 677         new_mpath->sdata = sdata;
 678         new_mpath->flags = 0;
 679         skb_queue_head_init(&new_mpath->frame_queue);
 680         new_node->mpath = new_mpath;
 681         init_timer(&new_mpath->timer);
 682         new_mpath->exp_time = jiffies;
 683         spin_lock_init(&new_mpath->state_lock);
 684
 685         tbl = resize_dereference_mpp_paths();
 686
 687         hash_idx = mesh_table_hash(dst, sdata, tbl);
 688         bucket = &tbl->hash_buckets[hash_idx];
 689
 690         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 691
 692         err = -EEXIST;
 693         hlist_for_each_entry(node, n, bucket, list) {
 694                 mpath = node->mpath;
 695                 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 696                         goto err_exists;
 697         }
 698
 699         hlist_add_head_rcu(&new_node->list, bucket);
 700         if (atomic_inc_return(&tbl->entries) >=
 701             tbl->mean_chain_len * (tbl->hash_mask + 1))
 702                 grow = 1;
 703
 704         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 705         read_unlock_bh(&pathtbl_resize_lock);
 706         if (grow) {
 707                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 708                 ieee80211_queue_work(&local->hw, &sdata->work);
 709         }
 710         return 0;
 711
 712 err_exists:
 713         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 714         read_unlock_bh(&pathtbl_resize_lock);
 715         kfree(new_node);
 716 err_node_alloc:
 717         kfree(new_mpath);
 718 err_path_alloc:
 719         return err;
 720 }
 721
 722
 723 /**
 724  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 725  *
 726  * @sta: broken peer link
 727  *
 728  * This function must be called from the rate control algorithm if enough
 729  * delivery errors suggest that a peer link is no longer usable.
 730  */
 731 void mesh_plink_broken(struct sta_info *sta)
 732 {
 733         struct mesh_table *tbl;
 734         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 735         struct mesh_path *mpath;
 736         struct mpath_node *node;
 737         struct hlist_node *p;
 738         struct ieee80211_sub_if_data *sdata = sta->sdata;
 739         int i;
 740         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 741
 742         rcu_read_lock();
 743         tbl = rcu_dereference(mesh_paths);
 744         for_each_mesh_entry(tbl, p, node, i) {
 745                 mpath = node->mpath;
 746                 if (rcu_dereference(mpath->next_hop) == sta &&
 747                     mpath->flags & MESH_PATH_ACTIVE &&
 748                     !(mpath->flags & MESH_PATH_FIXED)) {
 749                         spin_lock_bh(&mpath->state_lock);
 750                         mpath->flags &= ~MESH_PATH_ACTIVE;
 751                         ++mpath->sn;
 752                         spin_unlock_bh(&mpath->state_lock);
 753                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 754                                         mpath->dst, cpu_to_le32(mpath->sn),
 755                                         reason, bcast, sdata);
 756                 }
 757         }
 758         rcu_read_unlock();
 759 }
 760
 761 static void mesh_path_node_reclaim(struct rcu_head *rp)
 762 {
 763         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 764         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 765
 766         del_timer_sync(&node->mpath->timer);
 767         atomic_dec(&sdata->u.mesh.mpaths);
 768         kfree(node->mpath);
 769         kfree(node);
 770 }
 771
 772 /* needs to be called with the corresponding hashwlock taken */
 773 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 774 {
 775         struct mesh_path *mpath;
 776         mpath = node->mpath;
 777         spin_lock(&mpath->state_lock);
 778         mpath->flags |= MESH_PATH_RESOLVING;
 779         if (mpath->is_gate)
 780                 mesh_gate_del(tbl, mpath);
 781         hlist_del_rcu(&node->list);
 782         call_rcu(&node->rcu, mesh_path_node_reclaim);
 783         spin_unlock(&mpath->state_lock);
 784         atomic_dec(&tbl->entries);
 785 }
 786
 787 /**
 788  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 789  *
 790  * @sta - mesh peer to match
 791  *
 792  * RCU notes: this function is called when a mesh plink transitions from
 793  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 794  * allows path creation. This will happen before the sta can be freed (because
 795  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 796  * protected against the plink disappearing.
 797  */
 798 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 799 {
 800         struct mesh_table *tbl;
 801         struct mesh_path *mpath;
 802         struct mpath_node *node;
 803         struct hlist_node *p;
 804         int i;
 805
 806         rcu_read_lock();
 807         read_lock_bh(&pathtbl_resize_lock);
 808         tbl = resize_dereference_mesh_paths();
 809         for_each_mesh_entry(tbl, p, node, i) {
 810                 mpath = node->mpath;
 811                 if (rcu_dereference(mpath->next_hop) == sta) {
 812                         spin_lock_bh(&tbl->hashwlock[i]);
 813                         __mesh_path_del(tbl, node);
 814                         spin_unlock_bh(&tbl->hashwlock[i]);
 815                 }
 816         }
 817         read_unlock_bh(&pathtbl_resize_lock);
 818         rcu_read_unlock();
 819 }
 820
 821 static void table_flush_by_iface(struct mesh_table *tbl,
 822                                  struct ieee80211_sub_if_data *sdata)
 823 {
 824         struct mesh_path *mpath;
 825         struct mpath_node *node;
 826         struct hlist_node *p;
 827         int i;
 828
 829         WARN_ON(!rcu_read_lock_held());
 830         for_each_mesh_entry(tbl, p, node, i) {
 831                 mpath = node->mpath;
 832                 if (mpath->sdata != sdata)
 833                         continue;
 834                 spin_lock_bh(&tbl->hashwlock[i]);
 835                 __mesh_path_del(tbl, node);
 836                 spin_unlock_bh(&tbl->hashwlock[i]);
 837         }
 838 }
 839
 840 /**
 841  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 842  *
 843  * This function deletes both mesh paths as well as mesh portal paths.
 844  *
 845  * @sdata - interface data to match
 846  *
 847  */
 848 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 849 {
 850         struct mesh_table *tbl;
 851
 852         rcu_read_lock();
 853         read_lock_bh(&pathtbl_resize_lock);
 854         tbl = resize_dereference_mesh_paths();
 855         table_flush_by_iface(tbl, sdata);
 856         tbl = resize_dereference_mpp_paths();
 857         table_flush_by_iface(tbl, sdata);
 858         read_unlock_bh(&pathtbl_resize_lock);
 859         rcu_read_unlock();
 860 }
 861
 862 /**
 863  * mesh_path_del - delete a mesh path from the table
 864  *
 865  * @addr: dst address (ETH_ALEN length)
 866  * @sdata: local subif
 867  *
 868  * Returns: 0 if successful
 869  */
 870 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 871 {
 872         struct mesh_table *tbl;
 873         struct mesh_path *mpath;
 874         struct mpath_node *node;
 875         struct hlist_head *bucket;
 876         struct hlist_node *n;
 877         int hash_idx;
 878         int err = 0;
 879
 880         read_lock_bh(&pathtbl_resize_lock);
 881         tbl = resize_dereference_mesh_paths();
 882         hash_idx = mesh_table_hash(addr, sdata, tbl);
 883         bucket = &tbl->hash_buckets[hash_idx];
 884
 885         spin_lock_bh(&tbl->hashwlock[hash_idx]);
 886         hlist_for_each_entry(node, n, bucket, list) {
 887                 mpath = node->mpath;
 888                 if (mpath->sdata == sdata &&
 889                     memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
 890                         __mesh_path_del(tbl, node);
 891                         goto enddel;
 892                 }
 893         }
 894
 895         err = -ENXIO;
 896 enddel:
 897         mesh_paths_generation++;
 898         spin_unlock_bh(&tbl->hashwlock[hash_idx]);
 899         read_unlock_bh(&pathtbl_resize_lock);
 900         return err;
 901 }
 902
 903 /**
 904  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 905  *
 906  * @mpath: mesh path to activate
 907  *
 908  * Locking: the state_lock of the mpath structure must NOT be held when calling
 909  * this function.
 910  */
 911 void mesh_path_tx_pending(struct mesh_path *mpath)
 912 {
 913         if (mpath->flags & MESH_PATH_ACTIVE)
 914                 ieee80211_add_pending_skbs(mpath->sdata->local,
 915                                 &mpath->frame_queue);
 916 }
 917
 918 /**
 919  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 920  *
 921  * @mpath: mesh path whose queue will be emptied
 922  *
 923  * If there is only one gate, the frames are transferred from the failed mpath
 924  * queue to that gate's queue.  If there are more than one gates, the frames
 925  * are copied from each gate to the next.  After frames are copied, the
 926  * mpath queues are emptied onto the transmission queue.
 927  */
 928 int mesh_path_send_to_gates(struct mesh_path *mpath)
 929 {
 930         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 931         struct hlist_node *n;
 932         struct mesh_table *tbl;
 933         struct mesh_path *from_mpath = mpath;
 934         struct mpath_node *gate = NULL;
 935         bool copy = false;
 936         struct hlist_head *known_gates;
 937
 938         rcu_read_lock();
 939         tbl = rcu_dereference(mesh_paths);
 940         known_gates = tbl->known_gates;
 941         rcu_read_unlock();
 942
 943         if (!known_gates)
 944                 return -EHOSTUNREACH;
 945
 946         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
 947                 if (gate->mpath->sdata != sdata)
 948                         continue;
 949
 950                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 951                         mpath_dbg("Forwarding to %pM\n", gate->mpath->dst);
 952                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 953                         from_mpath = gate->mpath;
 954                         copy = true;
 955                 } else {
 956                         mpath_dbg("Not forwarding %p\n", gate->mpath);
 957                         mpath_dbg("flags %x\n", gate->mpath->flags);
 958                 }
 959         }
 960
 961         hlist_for_each_entry_rcu(gate, n, known_gates, list)
 962                 if (gate->mpath->sdata == sdata) {
 963                         mpath_dbg("Sending to %pM\n", gate->mpath->dst);
 964                         mesh_path_tx_pending(gate->mpath);
 965                 }
 966
 967         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 968 }
 969
 970 /**
 971  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 972  *
 973  * @skb: frame to discard
 974  * @sdata: network subif the frame was to be sent through
 975  *
 976  * Locking: the function must me called within a rcu_read_lock region
 977  */
 978 void mesh_path_discard_frame(struct sk_buff *skb,
 979                              struct ieee80211_sub_if_data *sdata)
 980 {
 981         kfree_skb(skb);
 982         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 983 }
 984
 985 /**
 986  * mesh_path_flush_pending - free the pending queue of a mesh path
 987  *
 988  * @mpath: mesh path whose queue has to be freed
 989  *
 990  * Locking: the function must me called within a rcu_read_lock region
 991  */
 992 void mesh_path_flush_pending(struct mesh_path *mpath)
 993 {
 994         struct sk_buff *skb;
 995
 996         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 997                 mesh_path_discard_frame(skb, mpath->sdata);
 998 }
 999
1000 /**
1001  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1002  *
1003  * @mpath: the mesh path to modify
1004  * @next_hop: the next hop to force
1005  *
1006  * Locking: this function must be called holding mpath->state_lock
1007  */
1008 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1009 {
1010         spin_lock_bh(&mpath->state_lock);
1011         mesh_path_assign_nexthop(mpath, next_hop);
1012         mpath->sn = 0xffff;
1013         mpath->metric = 0;
1014         mpath->hop_count = 0;
1015         mpath->exp_time = 0;
1016         mpath->flags |= MESH_PATH_FIXED;
1017         mesh_path_activate(mpath);
1018         spin_unlock_bh(&mpath->state_lock);
1019         mesh_path_tx_pending(mpath);
1020 }
1021
1022 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1023 {
1024         struct mesh_path *mpath;
1025         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1026         mpath = node->mpath;
1027         hlist_del_rcu(p);
1028         if (free_leafs) {
1029                 del_timer_sync(&mpath->timer);
1030                 kfree(mpath);
1031         }
1032         kfree(node);
1033 }
1034
1035 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1036 {
1037         struct mesh_path *mpath;
1038         struct mpath_node *node, *new_node;
1039         u32 hash_idx;
1040
1041         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1042         if (new_node == NULL)
1043                 return -ENOMEM;
1044
1045         node = hlist_entry(p, struct mpath_node, list);
1046         mpath = node->mpath;
1047         new_node->mpath = mpath;
1048         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1049         hlist_add_head(&new_node->list,
1050                         &newtbl->hash_buckets[hash_idx]);
1051         return 0;
1052 }
1053
1054 int mesh_pathtbl_init(void)
1055 {
1056         struct mesh_table *tbl_path, *tbl_mpp;
1057         int ret;
1058
1059         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1060         if (!tbl_path)
1061                 return -ENOMEM;
1062         tbl_path->free_node = &mesh_path_node_free;
1063         tbl_path->copy_node = &mesh_path_node_copy;
1064         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1065         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1066         if (!tbl_path->known_gates) {
1067                 ret = -ENOMEM;
1068                 goto free_path;
1069         }
1070         INIT_HLIST_HEAD(tbl_path->known_gates);
1071
1072
1073         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1074         if (!tbl_mpp) {
1075                 ret = -ENOMEM;
1076                 goto free_path;
1077         }
1078         tbl_mpp->free_node = &mesh_path_node_free;
1079         tbl_mpp->copy_node = &mesh_path_node_copy;
1080         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1081         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1082         if (!tbl_mpp->known_gates) {
1083                 ret = -ENOMEM;
1084                 goto free_mpp;
1085         }
1086         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1087
1088         /* Need no locking since this is during init */
1089         RCU_INIT_POINTER(mesh_paths, tbl_path);
1090         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1091
1092         return 0;
1093
1094 free_mpp:
1095         mesh_table_free(tbl_mpp, true);
1096 free_path:
1097         mesh_table_free(tbl_path, true);
1098         return ret;
1099 }
1100
1101 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1102 {
1103         struct mesh_table *tbl;
1104         struct mesh_path *mpath;
1105         struct mpath_node *node;
1106         struct hlist_node *p;
1107         int i;
1108
1109         rcu_read_lock();
1110         tbl = rcu_dereference(mesh_paths);
1111         for_each_mesh_entry(tbl, p, node, i) {
1112                 if (node->mpath->sdata != sdata)
1113                         continue;
1114                 mpath = node->mpath;
1115                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1116                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1117                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1118                         mesh_path_del(mpath->dst, mpath->sdata);
1119         }
1120         rcu_read_unlock();
1121 }
1122
1123 void mesh_pathtbl_unregister(void)
1124 {
1125         /* no need for locking during exit path */
1126         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1127         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1128 }