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