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