net/mac80211/mesh_pathtbl.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/etherdevice.h>
  11 #include <linux/list.h>
  12 #include <linux/random.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/string.h>
  16 #include <net/mac80211.h>
  17 #include "wme.h"
  18 #include "ieee80211_i.h"
  19 #include "mesh.h"
  20
  21 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  22 #define INIT_PATHS_SIZE_ORDER   2
  23
  24 /* Keep the mean chain length below this constant */
  25 #define MEAN_CHAIN_LEN          2
  26
  27 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  28                                 time_after(jiffies, mpath->exp_time) && \
  29                                 !(mpath->flags & MESH_PATH_FIXED))
  30
  31 struct mpath_node {
  32         struct hlist_node list;
  33         struct rcu_head rcu;
  34         /* This indirection allows two different tables to point to the same
  35          * mesh_path structure, useful when resizing
  36          */
  37         struct mesh_path *mpath;
  38 };
  39
  40 static struct mesh_table __rcu *mesh_paths;
  41 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
  42
  43 int mesh_paths_generation;
  44
  45 /* This lock will have the grow table function as writer and add / delete nodes
  46  * as readers. RCU provides sufficient protection only when reading the table
  47  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
  48  * the read lock or we risk operating on an old table.  The write lock is only
  49  * needed when modifying the number of buckets a table.
  50  */
  51 static DEFINE_RWLOCK(pathtbl_resize_lock);
  52
  53
  54 static inline struct mesh_table *resize_dereference_mesh_paths(void)
  55 {
  56         return rcu_dereference_protected(mesh_paths,
  57                 lockdep_is_held(&pathtbl_resize_lock));
  58 }
  59
  60 static inline struct mesh_table *resize_dereference_mpp_paths(void)
  61 {
  62         return rcu_dereference_protected(mpp_paths,
  63                 lockdep_is_held(&pathtbl_resize_lock));
  64 }
  65
  66 /*
  67  * CAREFUL -- "tbl" must not be an expression,
  68  * in particular not an rcu_dereference(), since
  69  * it's used twice. So it is illegal to do
  70  *      for_each_mesh_entry(rcu_dereference(...), ...)
  71  */
  72 #define for_each_mesh_entry(tbl, p, node, i) \
  73         for (i = 0; i <= tbl->hash_mask; i++) \
  74                 hlist_for_each_entry_rcu(node, p, &tbl->hash_buckets[i], list)
  75
  76
  77 static struct mesh_table *mesh_table_alloc(int size_order)
  78 {
  79         int i;
  80         struct mesh_table *newtbl;
  81
  82         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  83         if (!newtbl)
  84                 return NULL;
  85
  86         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
  87                         (1 << size_order), GFP_ATOMIC);
  88
  89         if (!newtbl->hash_buckets) {
  90                 kfree(newtbl);
  91                 return NULL;
  92         }
  93
  94         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
  95                         (1 << size_order), GFP_ATOMIC);
  96         if (!newtbl->hashwlock) {
  97                 kfree(newtbl->hash_buckets);
  98                 kfree(newtbl);
  99                 return NULL;
 100         }
 101
 102         newtbl->size_order = size_order;
 103         newtbl->hash_mask = (1 << size_order) - 1;
 104         atomic_set(&newtbl->entries,  0);
 105         get_random_bytes(&newtbl->hash_rnd,
 106                         sizeof(newtbl->hash_rnd));
 107         for (i = 0; i <= newtbl->hash_mask; i++)
 108                 spin_lock_init(&newtbl->hashwlock[i]);
 109         spin_lock_init(&newtbl->gates_lock);
 110
 111         return newtbl;
 112 }
 113
 114 static void __mesh_table_free(struct mesh_table *tbl)
 115 {
 116         kfree(tbl->hash_buckets);
 117         kfree(tbl->hashwlock);
 118         kfree(tbl);
 119 }
 120
 121 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 122 {
 123         struct hlist_head *mesh_hash;
 124         struct hlist_node *p, *q;
 125         struct mpath_node *gate;
 126         int i;
 127
 128         mesh_hash = tbl->hash_buckets;
 129         for (i = 0; i <= tbl->hash_mask; i++) {
 130                 spin_lock_bh(&tbl->hashwlock[i]);
 131                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 132                         tbl->free_node(p, free_leafs);
 133                         atomic_dec(&tbl->entries);
 134                 }
 135                 spin_unlock_bh(&tbl->hashwlock[i]);
 136         }
 137         if (free_leafs) {
 138                 spin_lock_bh(&tbl->gates_lock);
 139                 hlist_for_each_entry_safe(gate, p, q,
 140                                          tbl->known_gates, list) {
 141                         hlist_del(&gate->list);
 142                         kfree(gate);
 143                 }
 144                 kfree(tbl->known_gates);
 145                 spin_unlock_bh(&tbl->gates_lock);
 146         }
 147
 148         __mesh_table_free(tbl);
 149 }
 150
 151 static int mesh_table_grow(struct mesh_table *oldtbl,
 152                            struct mesh_table *newtbl)
 153 {
 154         struct hlist_head *oldhash;
 155         struct hlist_node *p, *q;
 156         int i;
 157
 158         if (atomic_read(&oldtbl->entries)
 159                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
 160                 return -EAGAIN;
 161
 162         newtbl->free_node = oldtbl->free_node;
 163         newtbl->mean_chain_len = oldtbl->mean_chain_len;
 164         newtbl->copy_node = oldtbl->copy_node;
 165         newtbl->known_gates = oldtbl->known_gates;
 166         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
 167
 168         oldhash = oldtbl->hash_buckets;
 169         for (i = 0; i <= oldtbl->hash_mask; i++)
 170                 hlist_for_each(p, &oldhash[i])
 171                         if (oldtbl->copy_node(p, newtbl) < 0)
 172                                 goto errcopy;
 173
 174         return 0;
 175
 176 errcopy:
 177         for (i = 0; i <= newtbl->hash_mask; i++) {
 178                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 179                         oldtbl->free_node(p, 0);
 180         }
 181         return -ENOMEM;
 182 }
 183
 184 static u32 mesh_table_hash(const u8 *addr, struct ieee80211_sub_if_data *sdata,
 185                            struct mesh_table *tbl)
 186 {
 187         /* Use last four bytes of hw addr and interface index as hash index */
 188         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
 189                 & tbl->hash_mask;
 190 }
 191
 192
 193 /**
 194  *
 195  * mesh_path_assign_nexthop - update mesh path next hop
 196  *
 197  * @mpath: mesh path to update
 198  * @sta: next hop to assign
 199  *
 200  * Locking: mpath->state_lock must be held when calling this function
 201  */
 202 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 203 {
 204         struct sk_buff *skb;
 205         struct ieee80211_hdr *hdr;
 206         unsigned long flags;
 207
 208         rcu_assign_pointer(mpath->next_hop, sta);
 209
 210         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 211         skb_queue_walk(&mpath->frame_queue, skb) {
 212                 hdr = (struct ieee80211_hdr *) skb->data;
 213                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 214                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 215                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 216         }
 217
 218         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 219 }
 220
 221 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 222                              struct mesh_path *gate_mpath)
 223 {
 224         struct ieee80211_hdr *hdr;
 225         struct ieee80211s_hdr *mshdr;
 226         int mesh_hdrlen, hdrlen;
 227         char *next_hop;
 228
 229         hdr = (struct ieee80211_hdr *) skb->data;
 230         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 231         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 232
 233         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 234                 /* size of the fixed part of the mesh header */
 235                 mesh_hdrlen = 6;
 236
 237                 /* make room for the two extended addresses */
 238                 skb_push(skb, 2 * ETH_ALEN);
 239                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 240
 241                 hdr = (struct ieee80211_hdr *) skb->data;
 242
 243                 /* we preserve the previous mesh header and only add
 244                  * the new addreses */
 245                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 246                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 247                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 248                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 249         }
 250
 251         /* update next hop */
 252         hdr = (struct ieee80211_hdr *) skb->data;
 253         rcu_read_lock();
 254         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 255         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 256         rcu_read_unlock();
 257         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 258         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 259 }
 260
 261 /**
 262  *
 263  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 264  *
 265  * This function is used to transfer or copy frames from an unresolved mpath to
 266  * a gate mpath.  The function also adds the Address Extension field and
 267  * updates the next hop.
 268  *
 269  * If a frame already has an Address Extension field, only the next hop and
 270  * destination addresses are updated.
 271  *
 272  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 273  *
 274  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 275  * @from_mpath: The failed mpath
 276  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 277  * move them.
 278  */
 279 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 280                                     struct mesh_path *from_mpath,
 281                                     bool copy)
 282 {
 283         struct sk_buff *skb, *fskb, *tmp;
 284         struct sk_buff_head failq;
 285         unsigned long flags;
 286
 287         BUG_ON(gate_mpath == from_mpath);
 288         BUG_ON(!gate_mpath->next_hop);
 289
 290         __skb_queue_head_init(&failq);
 291
 292         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 293         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 294         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 295
 296         skb_queue_walk_safe(&failq, fskb, tmp) {
 297                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 298                                   MESH_FRAME_QUEUE_LEN) {
 299                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 300                         break;
 301                 }
 302
 303                 skb = skb_copy(fskb, GFP_ATOMIC);
 304                 if (WARN_ON(!skb))
 305                         break;
 306
 307                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 308                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 309
 310                 if (copy)
 311                         continue;
 312
 313                 __skb_unlink(fskb, &failq);
 314                 kfree_skb(fskb);
 315         }
 316
 317         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 318                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 319
 320         if (!copy)
 321                 return;
 322
 323         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 324         skb_queue_splice(&failq, &from_mpath->frame_queue);
 325         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 326 }
 327
 328
 329 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 330                                       struct ieee80211_sub_if_data *sdata)
 331 {
 332         struct mesh_path *mpath;
 333         struct hlist_node *n;
 334         struct hlist_head *bucket;
 335         struct mpath_node *node;
 336
 337         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 338         hlist_for_each_entry_rcu(node, n, bucket, list) {
 339                 mpath = node->mpath;
 340                 if (mpath->sdata == sdata &&
 341                     ether_addr_equal(dst, mpath->dst)) {
 342                         if (MPATH_EXPIRED(mpath)) {
 343                                 spin_lock_bh(&mpath->state_lock);
 344                                 mpath->flags &= ~MESH_PATH_ACTIVE;
 345                                 spin_unlock_bh(&mpath->state_lock);
 346                         }
 347                         return mpath;
 348                 }
 349         }
 350         return NULL;
 351 }
 352
 353 /**
 354  * mesh_path_lookup - look up a path in the mesh path table
 355  * @dst: hardware address (ETH_ALEN length) of destination
 356  * @sdata: local subif
 357  *
 358  * Returns: pointer to the mesh path structure, or NULL if not found
 359  *
 360  * Locking: must be called within a read rcu section.
 361  */
 362 struct mesh_path *mesh_path_lookup(const u8 *dst,
 363                                    struct ieee80211_sub_if_data *sdata)
 364 {
 365         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
 366 }
 367
 368 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 369 {
 370         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
 371 }
 372
 373
 374 /**
 375  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 376  * @idx: index
 377  * @sdata: local subif, or NULL for all entries
 378  *
 379  * Returns: pointer to the mesh path structure, or NULL if not found.
 380  *
 381  * Locking: must be called within a read rcu section.
 382  */
 383 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 384 {
 385         struct mesh_table *tbl = rcu_dereference(mesh_paths);
 386         struct mpath_node *node;
 387         struct hlist_node *p;
 388         int i;
 389         int j = 0;
 390
 391         for_each_mesh_entry(tbl, p, node, i) {
 392                 if (sdata && node->mpath->sdata != sdata)
 393                         continue;
 394                 if (j++ == idx) {
 395                         if (MPATH_EXPIRED(node->mpath)) {
 396                                 spin_lock_bh(&node->mpath->state_lock);
 397                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
 398                                 spin_unlock_bh(&node->mpath->state_lock);
 399                         }
 400                         return node->mpath;
 401                 }
 402         }
 403
 404         return NULL;
 405 }
 406
 407 /**
 408  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 409  * @mpath: gate path to add to table
 410  */
 411 int mesh_path_add_gate(struct mesh_path *mpath)
 412 {
 413         struct mesh_table *tbl;
 414         struct mpath_node *gate, *new_gate;
 415         struct hlist_node *n;
 416         int err;
 417
 418         rcu_read_lock();
 419         tbl = rcu_dereference(mesh_paths);
 420
 421         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
 422                 if (gate->mpath == mpath) {
 423                         err = -EEXIST;
 424                         goto err_rcu;
 425                 }
 426
 427         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 428         if (!new_gate) {
 429                 err = -ENOMEM;
 430                 goto err_rcu;
 431         }
 432
 433         mpath->is_gate = true;
 434         mpath->sdata->u.mesh.num_gates++;
 435         new_gate->mpath = mpath;
 436         spin_lock_bh(&tbl->gates_lock);
 437         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
 438         spin_unlock_bh(&tbl->gates_lock);
 439         rcu_read_unlock();
 440         mpath_dbg(mpath->sdata,
 441                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 442                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 443         return 0;
 444 err_rcu:
 445         rcu_read_unlock();
 446         return err;
 447 }
 448
 449 /**
 450  * mesh_gate_del - remove a mesh gate from the list of known gates
 451  * @tbl: table which holds our list of known gates
 452  * @mpath: gate mpath
 453  *
 454  * Returns: 0 on success
 455  *
 456  * Locking: must be called inside rcu_read_lock() section
 457  */
 458 static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 459 {
 460         struct mpath_node *gate;
 461         struct hlist_node *p, *q;
 462
 463         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list)
 464                 if (gate->mpath == mpath) {
 465                         spin_lock_bh(&tbl->gates_lock);
 466                         hlist_del_rcu(&gate->list);
 467                         kfree_rcu(gate, rcu);
 468                         spin_unlock_bh(&tbl->gates_lock);
 469                         mpath->sdata->u.mesh.num_gates--;
 470                         mpath->is_gate = false;
 471                         mpath_dbg(mpath->sdata,
 472                                   "Mesh path: Deleted gate: %pM. %d known gates\n",
 473                                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 474                         break;
 475                 }
 476
 477         return 0;
 478 }
 479
 480 /**
 481  * mesh_gate_num - number of gates known to this interface
 482  * @sdata: subif data
 483  */
 484 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 485 {
 486         return sdata->u.mesh.num_gates;
 487 }
 488
 489 /**
 490  * mesh_path_add - allocate and add a new path to the mesh path table
 491  * @addr: destination address of the path (ETH_ALEN length)
 492  * @sdata: local subif
 493  *
 494  * Returns: 0 on success
 495  *
 496  * State: the initial state of the new path is set to 0
 497  */
 498 int mesh_path_add(const u8 *dst, struct ieee80211_sub_if_data *sdata)
 499 {
 500         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 501         struct ieee80211_local *local = sdata->local;
 502         struct mesh_table *tbl;
 503         struct mesh_path *mpath, *new_mpath;
 504         struct mpath_node *node, *new_node;
 505         struct hlist_head *bucket;
 506         struct hlist_node *n;
 507         int grow = 0;
 508         int err = 0;
 509         u32 hash_idx;
 510
 511         if (ether_addr_equal(dst, sdata->vif.addr))
 512                 /* never add ourselves as neighbours */
 513                 return -ENOTSUPP;
 514
 515         if (is_multicast_ether_addr(dst))
 516                 return -ENOTSUPP;
 517
 518         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 519                 return -ENOSPC;
 520
 521         err = -ENOMEM;
 522         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 523         if (!new_mpath)
 524                 goto err_path_alloc;
 525
 526         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 527         if (!new_node)
 528                 goto err_node_alloc;
 529
 530         read_lock_bh(&pathtbl_resize_lock);
 531         memcpy(new_mpath->dst, dst, ETH_ALEN);
 532         eth_broadcast_addr(new_mpath->rann_snd_addr);
 533         new_mpath->is_root = false;
 534         new_mpath->sdata = sdata;
 535         new_mpath->flags = 0;
 536         skb_queue_head_init(&new_mpath->frame_queue);
 537         new_node->mpath = new_mpath;
 538         new_mpath->timer.data = (unsigned long) new_mpath;
 539         new_mpath->timer.function = mesh_path_timer;
 540         new_mpath->exp_time = jiffies;
 541         spin_lock_init(&new_mpath->state_lock);
 542         init_timer(&new_mpath->timer);
 543
 544         tbl = resize_dereference_mesh_paths();
 545
 546         hash_idx = mesh_table_hash(dst, sdata, tbl);
 547         bucket = &tbl->hash_buckets[hash_idx];
 548
 549         spin_lock(&tbl->hashwlock[hash_idx]);
 550
 551         err = -EEXIST;
 552         hlist_for_each_entry(node, n, bucket, list) {
 553                 mpath = node->mpath;
 554                 if (mpath->sdata == sdata &&
 555                     ether_addr_equal(dst, mpath->dst))
 556                         goto err_exists;
 557         }
 558
 559         hlist_add_head_rcu(&new_node->list, bucket);
 560         if (atomic_inc_return(&tbl->entries) >=
 561             tbl->mean_chain_len * (tbl->hash_mask + 1))
 562                 grow = 1;
 563
 564         mesh_paths_generation++;
 565
 566         spin_unlock(&tbl->hashwlock[hash_idx]);
 567         read_unlock_bh(&pathtbl_resize_lock);
 568         if (grow) {
 569                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 570                 ieee80211_queue_work(&local->hw, &sdata->work);
 571         }
 572         return 0;
 573
 574 err_exists:
 575         spin_unlock(&tbl->hashwlock[hash_idx]);
 576         read_unlock_bh(&pathtbl_resize_lock);
 577         kfree(new_node);
 578 err_node_alloc:
 579         kfree(new_mpath);
 580 err_path_alloc:
 581         atomic_dec(&sdata->u.mesh.mpaths);
 582         return err;
 583 }
 584
 585 static void mesh_table_free_rcu(struct rcu_head *rcu)
 586 {
 587         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
 588
 589         mesh_table_free(tbl, false);
 590 }
 591
 592 void mesh_mpath_table_grow(void)
 593 {
 594         struct mesh_table *oldtbl, *newtbl;
 595
 596         write_lock_bh(&pathtbl_resize_lock);
 597         oldtbl = resize_dereference_mesh_paths();
 598         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 599         if (!newtbl)
 600                 goto out;
 601         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 602                 __mesh_table_free(newtbl);
 603                 goto out;
 604         }
 605         rcu_assign_pointer(mesh_paths, newtbl);
 606
 607         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 608
 609  out:
 610         write_unlock_bh(&pathtbl_resize_lock);
 611 }
 612
 613 void mesh_mpp_table_grow(void)
 614 {
 615         struct mesh_table *oldtbl, *newtbl;
 616
 617         write_lock_bh(&pathtbl_resize_lock);
 618         oldtbl = resize_dereference_mpp_paths();
 619         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
 620         if (!newtbl)
 621                 goto out;
 622         if (mesh_table_grow(oldtbl, newtbl) < 0) {
 623                 __mesh_table_free(newtbl);
 624                 goto out;
 625         }
 626         rcu_assign_pointer(mpp_paths, newtbl);
 627         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
 628
 629  out:
 630         write_unlock_bh(&pathtbl_resize_lock);
 631 }
 632
 633 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 634 {
 635         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 636         struct ieee80211_local *local = sdata->local;
 637         struct mesh_table *tbl;
 638         struct mesh_path *mpath, *new_mpath;
 639         struct mpath_node *node, *new_node;
 640         struct hlist_head *bucket;
 641         struct hlist_node *n;
 642         int grow = 0;
 643         int err = 0;
 644         u32 hash_idx;
 645
 646         if (ether_addr_equal(dst, sdata->vif.addr))
 647                 /* never add ourselves as neighbours */
 648                 return -ENOTSUPP;
 649
 650         if (is_multicast_ether_addr(dst))
 651                 return -ENOTSUPP;
 652
 653         err = -ENOMEM;
 654         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 655         if (!new_mpath)
 656                 goto err_path_alloc;
 657
 658         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 659         if (!new_node)
 660                 goto err_node_alloc;
 661
 662         read_lock_bh(&pathtbl_resize_lock);
 663         memcpy(new_mpath->dst, dst, ETH_ALEN);
 664         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 665         new_mpath->sdata = sdata;
 666         new_mpath->flags = 0;
 667         skb_queue_head_init(&new_mpath->frame_queue);
 668         new_node->mpath = new_mpath;
 669         init_timer(&new_mpath->timer);
 670         new_mpath->exp_time = jiffies;
 671         spin_lock_init(&new_mpath->state_lock);
 672
 673         tbl = resize_dereference_mpp_paths();
 674
 675         hash_idx = mesh_table_hash(dst, sdata, tbl);
 676         bucket = &tbl->hash_buckets[hash_idx];
 677
 678         spin_lock(&tbl->hashwlock[hash_idx]);
 679
 680         err = -EEXIST;
 681         hlist_for_each_entry(node, n, bucket, list) {
 682                 mpath = node->mpath;
 683                 if (mpath->sdata == sdata &&
 684                     ether_addr_equal(dst, mpath->dst))
 685                         goto err_exists;
 686         }
 687
 688         hlist_add_head_rcu(&new_node->list, bucket);
 689         if (atomic_inc_return(&tbl->entries) >=
 690             tbl->mean_chain_len * (tbl->hash_mask + 1))
 691                 grow = 1;
 692
 693         spin_unlock(&tbl->hashwlock[hash_idx]);
 694         read_unlock_bh(&pathtbl_resize_lock);
 695         if (grow) {
 696                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 697                 ieee80211_queue_work(&local->hw, &sdata->work);
 698         }
 699         return 0;
 700
 701 err_exists:
 702         spin_unlock(&tbl->hashwlock[hash_idx]);
 703         read_unlock_bh(&pathtbl_resize_lock);
 704         kfree(new_node);
 705 err_node_alloc:
 706         kfree(new_mpath);
 707 err_path_alloc:
 708         return err;
 709 }
 710
 711
 712 /**
 713  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 714  *
 715  * @sta: broken peer link
 716  *
 717  * This function must be called from the rate control algorithm if enough
 718  * delivery errors suggest that a peer link is no longer usable.
 719  */
 720 void mesh_plink_broken(struct sta_info *sta)
 721 {
 722         struct mesh_table *tbl;
 723         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 724         struct mesh_path *mpath;
 725         struct mpath_node *node;
 726         struct hlist_node *p;
 727         struct ieee80211_sub_if_data *sdata = sta->sdata;
 728         int i;
 729         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
 730
 731         rcu_read_lock();
 732         tbl = rcu_dereference(mesh_paths);
 733         for_each_mesh_entry(tbl, p, node, i) {
 734                 mpath = node->mpath;
 735                 if (rcu_dereference(mpath->next_hop) == sta &&
 736                     mpath->flags & MESH_PATH_ACTIVE &&
 737                     !(mpath->flags & MESH_PATH_FIXED)) {
 738                         spin_lock_bh(&mpath->state_lock);
 739                         mpath->flags &= ~MESH_PATH_ACTIVE;
 740                         ++mpath->sn;
 741                         spin_unlock_bh(&mpath->state_lock);
 742                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
 743                                         mpath->dst, cpu_to_le32(mpath->sn),
 744                                         reason, bcast, sdata);
 745                 }
 746         }
 747         rcu_read_unlock();
 748 }
 749
 750 static void mesh_path_node_reclaim(struct rcu_head *rp)
 751 {
 752         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 753         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 754
 755         del_timer_sync(&node->mpath->timer);
 756         atomic_dec(&sdata->u.mesh.mpaths);
 757         kfree(node->mpath);
 758         kfree(node);
 759 }
 760
 761 /* needs to be called with the corresponding hashwlock taken */
 762 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
 763 {
 764         struct mesh_path *mpath;
 765         mpath = node->mpath;
 766         spin_lock(&mpath->state_lock);
 767         mpath->flags |= MESH_PATH_RESOLVING;
 768         if (mpath->is_gate)
 769                 mesh_gate_del(tbl, mpath);
 770         hlist_del_rcu(&node->list);
 771         call_rcu(&node->rcu, mesh_path_node_reclaim);
 772         spin_unlock(&mpath->state_lock);
 773         atomic_dec(&tbl->entries);
 774 }
 775
 776 /**
 777  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 778  *
 779  * @sta: mesh peer to match
 780  *
 781  * RCU notes: this function is called when a mesh plink transitions from
 782  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 783  * allows path creation. This will happen before the sta can be freed (because
 784  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 785  * protected against the plink disappearing.
 786  */
 787 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 788 {
 789         struct mesh_table *tbl;
 790         struct mesh_path *mpath;
 791         struct mpath_node *node;
 792         struct hlist_node *p;
 793         int i;
 794
 795         rcu_read_lock();
 796         read_lock_bh(&pathtbl_resize_lock);
 797         tbl = resize_dereference_mesh_paths();
 798         for_each_mesh_entry(tbl, p, node, i) {
 799                 mpath = node->mpath;
 800                 if (rcu_dereference(mpath->next_hop) == sta) {
 801                         spin_lock(&tbl->hashwlock[i]);
 802                         __mesh_path_del(tbl, node);
 803                         spin_unlock(&tbl->hashwlock[i]);
 804                 }
 805         }
 806         read_unlock_bh(&pathtbl_resize_lock);
 807         rcu_read_unlock();
 808 }
 809
 810 static void table_flush_by_iface(struct mesh_table *tbl,
 811                                  struct ieee80211_sub_if_data *sdata)
 812 {
 813         struct mesh_path *mpath;
 814         struct mpath_node *node;
 815         struct hlist_node *p;
 816         int i;
 817
 818         WARN_ON(!rcu_read_lock_held());
 819         for_each_mesh_entry(tbl, p, node, i) {
 820                 mpath = node->mpath;
 821                 if (mpath->sdata != sdata)
 822                         continue;
 823                 spin_lock_bh(&tbl->hashwlock[i]);
 824                 __mesh_path_del(tbl, node);
 825                 spin_unlock_bh(&tbl->hashwlock[i]);
 826         }
 827 }
 828
 829 /**
 830  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 831  *
 832  * This function deletes both mesh paths as well as mesh portal paths.
 833  *
 834  * @sdata: interface data to match
 835  *
 836  */
 837 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 838 {
 839         struct mesh_table *tbl;
 840
 841         rcu_read_lock();
 842         read_lock_bh(&pathtbl_resize_lock);
 843         tbl = resize_dereference_mesh_paths();
 844         table_flush_by_iface(tbl, sdata);
 845         tbl = resize_dereference_mpp_paths();
 846         table_flush_by_iface(tbl, sdata);
 847         read_unlock_bh(&pathtbl_resize_lock);
 848         rcu_read_unlock();
 849 }
 850
 851 /**
 852  * mesh_path_del - delete a mesh path from the table
 853  *
 854  * @addr: dst address (ETH_ALEN length)
 855  * @sdata: local subif
 856  *
 857  * Returns: 0 if successful
 858  */
 859 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 860 {
 861         struct mesh_table *tbl;
 862         struct mesh_path *mpath;
 863         struct mpath_node *node;
 864         struct hlist_head *bucket;
 865         struct hlist_node *n;
 866         int hash_idx;
 867         int err = 0;
 868
 869         read_lock_bh(&pathtbl_resize_lock);
 870         tbl = resize_dereference_mesh_paths();
 871         hash_idx = mesh_table_hash(addr, sdata, tbl);
 872         bucket = &tbl->hash_buckets[hash_idx];
 873
 874         spin_lock(&tbl->hashwlock[hash_idx]);
 875         hlist_for_each_entry(node, n, bucket, list) {
 876                 mpath = node->mpath;
 877                 if (mpath->sdata == sdata &&
 878                     ether_addr_equal(addr, mpath->dst)) {
 879                         __mesh_path_del(tbl, node);
 880                         goto enddel;
 881                 }
 882         }
 883
 884         err = -ENXIO;
 885 enddel:
 886         mesh_paths_generation++;
 887         spin_unlock(&tbl->hashwlock[hash_idx]);
 888         read_unlock_bh(&pathtbl_resize_lock);
 889         return err;
 890 }
 891
 892 /**
 893  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 894  *
 895  * @mpath: mesh path to activate
 896  *
 897  * Locking: the state_lock of the mpath structure must NOT be held when calling
 898  * this function.
 899  */
 900 void mesh_path_tx_pending(struct mesh_path *mpath)
 901 {
 902         if (mpath->flags & MESH_PATH_ACTIVE)
 903                 ieee80211_add_pending_skbs(mpath->sdata->local,
 904                                 &mpath->frame_queue);
 905 }
 906
 907 /**
 908  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 909  *
 910  * @mpath: mesh path whose queue will be emptied
 911  *
 912  * If there is only one gate, the frames are transferred from the failed mpath
 913  * queue to that gate's queue.  If there are more than one gates, the frames
 914  * are copied from each gate to the next.  After frames are copied, the
 915  * mpath queues are emptied onto the transmission queue.
 916  */
 917 int mesh_path_send_to_gates(struct mesh_path *mpath)
 918 {
 919         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 920         struct hlist_node *n;
 921         struct mesh_table *tbl;
 922         struct mesh_path *from_mpath = mpath;
 923         struct mpath_node *gate = NULL;
 924         bool copy = false;
 925         struct hlist_head *known_gates;
 926
 927         rcu_read_lock();
 928         tbl = rcu_dereference(mesh_paths);
 929         known_gates = tbl->known_gates;
 930         rcu_read_unlock();
 931
 932         if (!known_gates)
 933                 return -EHOSTUNREACH;
 934
 935         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
 936                 if (gate->mpath->sdata != sdata)
 937                         continue;
 938
 939                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
 940                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
 941                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
 942                         from_mpath = gate->mpath;
 943                         copy = true;
 944                 } else {
 945                         mpath_dbg(sdata,
 946                                   "Not forwarding %p (flags %#x)\n",
 947                                   gate->mpath, gate->mpath->flags);
 948                 }
 949         }
 950
 951         hlist_for_each_entry_rcu(gate, n, known_gates, list)
 952                 if (gate->mpath->sdata == sdata) {
 953                         mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
 954                         mesh_path_tx_pending(gate->mpath);
 955                 }
 956
 957         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 958 }
 959
 960 /**
 961  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 962  *
 963  * @skb: frame to discard
 964  * @sdata: network subif the frame was to be sent through
 965  *
 966  * Locking: the function must me called within a rcu_read_lock region
 967  */
 968 void mesh_path_discard_frame(struct sk_buff *skb,
 969                              struct ieee80211_sub_if_data *sdata)
 970 {
 971         kfree_skb(skb);
 972         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 973 }
 974
 975 /**
 976  * mesh_path_flush_pending - free the pending queue of a mesh path
 977  *
 978  * @mpath: mesh path whose queue has to be freed
 979  *
 980  * Locking: the function must me called within a rcu_read_lock region
 981  */
 982 void mesh_path_flush_pending(struct mesh_path *mpath)
 983 {
 984         struct sk_buff *skb;
 985
 986         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 987                 mesh_path_discard_frame(skb, mpath->sdata);
 988 }
 989
 990 /**
 991  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 992  *
 993  * @mpath: the mesh path to modify
 994  * @next_hop: the next hop to force
 995  *
 996  * Locking: this function must be called holding mpath->state_lock
 997  */
 998 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 999 {
1000         spin_lock_bh(&mpath->state_lock);
1001         mesh_path_assign_nexthop(mpath, next_hop);
1002         mpath->sn = 0xffff;
1003         mpath->metric = 0;
1004         mpath->hop_count = 0;
1005         mpath->exp_time = 0;
1006         mpath->flags |= MESH_PATH_FIXED;
1007         mesh_path_activate(mpath);
1008         spin_unlock_bh(&mpath->state_lock);
1009         mesh_path_tx_pending(mpath);
1010 }
1011
1012 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1013 {
1014         struct mesh_path *mpath;
1015         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1016         mpath = node->mpath;
1017         hlist_del_rcu(p);
1018         if (free_leafs) {
1019                 del_timer_sync(&mpath->timer);
1020                 kfree(mpath);
1021         }
1022         kfree(node);
1023 }
1024
1025 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1026 {
1027         struct mesh_path *mpath;
1028         struct mpath_node *node, *new_node;
1029         u32 hash_idx;
1030
1031         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1032         if (new_node == NULL)
1033                 return -ENOMEM;
1034
1035         node = hlist_entry(p, struct mpath_node, list);
1036         mpath = node->mpath;
1037         new_node->mpath = mpath;
1038         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1039         hlist_add_head(&new_node->list,
1040                         &newtbl->hash_buckets[hash_idx]);
1041         return 0;
1042 }
1043
1044 int mesh_pathtbl_init(void)
1045 {
1046         struct mesh_table *tbl_path, *tbl_mpp;
1047         int ret;
1048
1049         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1050         if (!tbl_path)
1051                 return -ENOMEM;
1052         tbl_path->free_node = &mesh_path_node_free;
1053         tbl_path->copy_node = &mesh_path_node_copy;
1054         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1055         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1056         if (!tbl_path->known_gates) {
1057                 ret = -ENOMEM;
1058                 goto free_path;
1059         }
1060         INIT_HLIST_HEAD(tbl_path->known_gates);
1061
1062
1063         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1064         if (!tbl_mpp) {
1065                 ret = -ENOMEM;
1066                 goto free_path;
1067         }
1068         tbl_mpp->free_node = &mesh_path_node_free;
1069         tbl_mpp->copy_node = &mesh_path_node_copy;
1070         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1071         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1072         if (!tbl_mpp->known_gates) {
1073                 ret = -ENOMEM;
1074                 goto free_mpp;
1075         }
1076         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1077
1078         /* Need no locking since this is during init */
1079         RCU_INIT_POINTER(mesh_paths, tbl_path);
1080         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1081
1082         return 0;
1083
1084 free_mpp:
1085         mesh_table_free(tbl_mpp, true);
1086 free_path:
1087         mesh_table_free(tbl_path, true);
1088         return ret;
1089 }
1090
1091 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1092 {
1093         struct mesh_table *tbl;
1094         struct mesh_path *mpath;
1095         struct mpath_node *node;
1096         struct hlist_node *p;
1097         int i;
1098
1099         rcu_read_lock();
1100         tbl = rcu_dereference(mesh_paths);
1101         for_each_mesh_entry(tbl, p, node, i) {
1102                 if (node->mpath->sdata != sdata)
1103                         continue;
1104                 mpath = node->mpath;
1105                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1106                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1107                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1108                         mesh_path_del(mpath->dst, mpath->sdata);
1109         }
1110         rcu_read_unlock();
1111 }
1112
1113 void mesh_pathtbl_unregister(void)
1114 {
1115         /* no need for locking during exit path */
1116         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1117         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1118 }