net/mac80211/mesh_pathtbl.c

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