linux/net/mac80211/mesh_pathtbl.c
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   1/*
   2 * Copyright (c) 2008 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/spinlock.h>
  14#include <linux/string.h>
  15#include <net/mac80211.h>
  16#include "ieee80211_i.h"
  17#include "mesh.h"
  18
  19/* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
  20#define INIT_PATHS_SIZE_ORDER   2
  21
  22/* Keep the mean chain length below this constant */
  23#define MEAN_CHAIN_LEN          2
  24
  25#define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
  26                                time_after(jiffies, mpath->exp_time) && \
  27                                !(mpath->flags & MESH_PATH_FIXED))
  28
  29struct mpath_node {
  30        struct hlist_node list;
  31        struct rcu_head rcu;
  32        /* This indirection allows two different tables to point to the same
  33         * mesh_path structure, useful when resizing
  34         */
  35        struct mesh_path *mpath;
  36};
  37
  38static struct mesh_table *mesh_paths;
  39static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
  40
  41int mesh_paths_generation;
  42static void __mesh_table_free(struct mesh_table *tbl)
  43{
  44        kfree(tbl->hash_buckets);
  45        kfree(tbl->hashwlock);
  46        kfree(tbl);
  47}
  48
  49void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
  50{
  51        struct hlist_head *mesh_hash;
  52        struct hlist_node *p, *q;
  53        int i;
  54
  55        mesh_hash = tbl->hash_buckets;
  56        for (i = 0; i <= tbl->hash_mask; i++) {
  57                spin_lock(&tbl->hashwlock[i]);
  58                hlist_for_each_safe(p, q, &mesh_hash[i]) {
  59                        tbl->free_node(p, free_leafs);
  60                        atomic_dec(&tbl->entries);
  61                }
  62                spin_unlock(&tbl->hashwlock[i]);
  63        }
  64        __mesh_table_free(tbl);
  65}
  66
  67static struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
  68{
  69        struct mesh_table *newtbl;
  70        struct hlist_head *oldhash;
  71        struct hlist_node *p, *q;
  72        int i;
  73
  74        if (atomic_read(&tbl->entries)
  75                        < tbl->mean_chain_len * (tbl->hash_mask + 1))
  76                goto endgrow;
  77
  78        newtbl = mesh_table_alloc(tbl->size_order + 1);
  79        if (!newtbl)
  80                goto endgrow;
  81
  82        newtbl->free_node = tbl->free_node;
  83        newtbl->mean_chain_len = tbl->mean_chain_len;
  84        newtbl->copy_node = tbl->copy_node;
  85        atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
  86
  87        oldhash = tbl->hash_buckets;
  88        for (i = 0; i <= tbl->hash_mask; i++)
  89                hlist_for_each(p, &oldhash[i])
  90                        if (tbl->copy_node(p, newtbl) < 0)
  91                                goto errcopy;
  92
  93        return newtbl;
  94
  95errcopy:
  96        for (i = 0; i <= newtbl->hash_mask; i++) {
  97                hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
  98                        tbl->free_node(p, 0);
  99        }
 100        __mesh_table_free(newtbl);
 101endgrow:
 102        return NULL;
 103}
 104
 105
 106/* This lock will have the grow table function as writer and add / delete nodes
 107 * as readers. When reading the table (i.e. doing lookups) we are well protected
 108 * by RCU
 109 */
 110static DEFINE_RWLOCK(pathtbl_resize_lock);
 111
 112/**
 113 *
 114 * mesh_path_assign_nexthop - update mesh path next hop
 115 *
 116 * @mpath: mesh path to update
 117 * @sta: next hop to assign
 118 *
 119 * Locking: mpath->state_lock must be held when calling this function
 120 */
 121void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 122{
 123        struct sk_buff *skb;
 124        struct ieee80211_hdr *hdr;
 125        struct sk_buff_head tmpq;
 126        unsigned long flags;
 127
 128        rcu_assign_pointer(mpath->next_hop, sta);
 129
 130        __skb_queue_head_init(&tmpq);
 131
 132        spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 133
 134        while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
 135                hdr = (struct ieee80211_hdr *) skb->data;
 136                memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 137                __skb_queue_tail(&tmpq, skb);
 138        }
 139
 140        skb_queue_splice(&tmpq, &mpath->frame_queue);
 141        spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 142}
 143
 144
 145/**
 146 * mesh_path_lookup - look up a path in the mesh path table
 147 * @dst: hardware address (ETH_ALEN length) of destination
 148 * @sdata: local subif
 149 *
 150 * Returns: pointer to the mesh path structure, or NULL if not found
 151 *
 152 * Locking: must be called within a read rcu section.
 153 */
 154struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 155{
 156        struct mesh_path *mpath;
 157        struct hlist_node *n;
 158        struct hlist_head *bucket;
 159        struct mesh_table *tbl;
 160        struct mpath_node *node;
 161
 162        tbl = rcu_dereference(mesh_paths);
 163
 164        bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 165        hlist_for_each_entry_rcu(node, n, bucket, list) {
 166                mpath = node->mpath;
 167                if (mpath->sdata == sdata &&
 168                                memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 169                        if (MPATH_EXPIRED(mpath)) {
 170                                spin_lock_bh(&mpath->state_lock);
 171                                if (MPATH_EXPIRED(mpath))
 172                                        mpath->flags &= ~MESH_PATH_ACTIVE;
 173                                spin_unlock_bh(&mpath->state_lock);
 174                        }
 175                        return mpath;
 176                }
 177        }
 178        return NULL;
 179}
 180
 181struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 182{
 183        struct mesh_path *mpath;
 184        struct hlist_node *n;
 185        struct hlist_head *bucket;
 186        struct mesh_table *tbl;
 187        struct mpath_node *node;
 188
 189        tbl = rcu_dereference(mpp_paths);
 190
 191        bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
 192        hlist_for_each_entry_rcu(node, n, bucket, list) {
 193                mpath = node->mpath;
 194                if (mpath->sdata == sdata &&
 195                    memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
 196                        if (MPATH_EXPIRED(mpath)) {
 197                                spin_lock_bh(&mpath->state_lock);
 198                                if (MPATH_EXPIRED(mpath))
 199                                        mpath->flags &= ~MESH_PATH_ACTIVE;
 200                                spin_unlock_bh(&mpath->state_lock);
 201                        }
 202                        return mpath;
 203                }
 204        }
 205        return NULL;
 206}
 207
 208
 209/**
 210 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 211 * @idx: index
 212 * @sdata: local subif, or NULL for all entries
 213 *
 214 * Returns: pointer to the mesh path structure, or NULL if not found.
 215 *
 216 * Locking: must be called within a read rcu section.
 217 */
 218struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
 219{
 220        struct mpath_node *node;
 221        struct hlist_node *p;
 222        int i;
 223        int j = 0;
 224
 225        for_each_mesh_entry(mesh_paths, p, node, i) {
 226                if (sdata && node->mpath->sdata != sdata)
 227                        continue;
 228                if (j++ == idx) {
 229                        if (MPATH_EXPIRED(node->mpath)) {
 230                                spin_lock_bh(&node->mpath->state_lock);
 231                                if (MPATH_EXPIRED(node->mpath))
 232                                        node->mpath->flags &= ~MESH_PATH_ACTIVE;
 233                                spin_unlock_bh(&node->mpath->state_lock);
 234                        }
 235                        return node->mpath;
 236                }
 237        }
 238
 239        return NULL;
 240}
 241
 242/**
 243 * mesh_path_add - allocate and add a new path to the mesh path table
 244 * @addr: destination address of the path (ETH_ALEN length)
 245 * @sdata: local subif
 246 *
 247 * Returns: 0 on sucess
 248 *
 249 * State: the initial state of the new path is set to 0
 250 */
 251int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 252{
 253        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 254        struct ieee80211_local *local = sdata->local;
 255        struct mesh_path *mpath, *new_mpath;
 256        struct mpath_node *node, *new_node;
 257        struct hlist_head *bucket;
 258        struct hlist_node *n;
 259        int grow = 0;
 260        int err = 0;
 261        u32 hash_idx;
 262
 263        if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
 264                /* never add ourselves as neighbours */
 265                return -ENOTSUPP;
 266
 267        if (is_multicast_ether_addr(dst))
 268                return -ENOTSUPP;
 269
 270        if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 271                return -ENOSPC;
 272
 273        err = -ENOMEM;
 274        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 275        if (!new_mpath)
 276                goto err_path_alloc;
 277
 278        new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 279        if (!new_node)
 280                goto err_node_alloc;
 281
 282        read_lock(&pathtbl_resize_lock);
 283        memcpy(new_mpath->dst, dst, ETH_ALEN);
 284        new_mpath->sdata = sdata;
 285        new_mpath->flags = 0;
 286        skb_queue_head_init(&new_mpath->frame_queue);
 287        new_node->mpath = new_mpath;
 288        new_mpath->timer.data = (unsigned long) new_mpath;
 289        new_mpath->timer.function = mesh_path_timer;
 290        new_mpath->exp_time = jiffies;
 291        spin_lock_init(&new_mpath->state_lock);
 292        init_timer(&new_mpath->timer);
 293
 294        hash_idx = mesh_table_hash(dst, sdata, mesh_paths);
 295        bucket = &mesh_paths->hash_buckets[hash_idx];
 296
 297        spin_lock(&mesh_paths->hashwlock[hash_idx]);
 298
 299        err = -EEXIST;
 300        hlist_for_each_entry(node, n, bucket, list) {
 301                mpath = node->mpath;
 302                if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 303                        goto err_exists;
 304        }
 305
 306        hlist_add_head_rcu(&new_node->list, bucket);
 307        if (atomic_inc_return(&mesh_paths->entries) >=
 308                mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
 309                grow = 1;
 310
 311        mesh_paths_generation++;
 312
 313        spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 314        read_unlock(&pathtbl_resize_lock);
 315        if (grow) {
 316                set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
 317                ieee80211_queue_work(&local->hw, &ifmsh->work);
 318        }
 319        return 0;
 320
 321err_exists:
 322        spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 323        read_unlock(&pathtbl_resize_lock);
 324        kfree(new_node);
 325err_node_alloc:
 326        kfree(new_mpath);
 327err_path_alloc:
 328        atomic_dec(&sdata->u.mesh.mpaths);
 329        return err;
 330}
 331
 332void mesh_mpath_table_grow(void)
 333{
 334        struct mesh_table *oldtbl, *newtbl;
 335
 336        write_lock(&pathtbl_resize_lock);
 337        oldtbl = mesh_paths;
 338        newtbl = mesh_table_grow(mesh_paths);
 339        if (!newtbl) {
 340                write_unlock(&pathtbl_resize_lock);
 341                return;
 342        }
 343        rcu_assign_pointer(mesh_paths, newtbl);
 344        write_unlock(&pathtbl_resize_lock);
 345
 346        synchronize_rcu();
 347        mesh_table_free(oldtbl, false);
 348}
 349
 350void mesh_mpp_table_grow(void)
 351{
 352        struct mesh_table *oldtbl, *newtbl;
 353
 354        write_lock(&pathtbl_resize_lock);
 355        oldtbl = mpp_paths;
 356        newtbl = mesh_table_grow(mpp_paths);
 357        if (!newtbl) {
 358                write_unlock(&pathtbl_resize_lock);
 359                return;
 360        }
 361        rcu_assign_pointer(mpp_paths, newtbl);
 362        write_unlock(&pathtbl_resize_lock);
 363
 364        synchronize_rcu();
 365        mesh_table_free(oldtbl, false);
 366}
 367
 368int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 369{
 370        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 371        struct ieee80211_local *local = sdata->local;
 372        struct mesh_path *mpath, *new_mpath;
 373        struct mpath_node *node, *new_node;
 374        struct hlist_head *bucket;
 375        struct hlist_node *n;
 376        int grow = 0;
 377        int err = 0;
 378        u32 hash_idx;
 379
 380        if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
 381                /* never add ourselves as neighbours */
 382                return -ENOTSUPP;
 383
 384        if (is_multicast_ether_addr(dst))
 385                return -ENOTSUPP;
 386
 387        err = -ENOMEM;
 388        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
 389        if (!new_mpath)
 390                goto err_path_alloc;
 391
 392        new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 393        if (!new_node)
 394                goto err_node_alloc;
 395
 396        read_lock(&pathtbl_resize_lock);
 397        memcpy(new_mpath->dst, dst, ETH_ALEN);
 398        memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 399        new_mpath->sdata = sdata;
 400        new_mpath->flags = 0;
 401        skb_queue_head_init(&new_mpath->frame_queue);
 402        new_node->mpath = new_mpath;
 403        new_mpath->exp_time = jiffies;
 404        spin_lock_init(&new_mpath->state_lock);
 405
 406        hash_idx = mesh_table_hash(dst, sdata, mpp_paths);
 407        bucket = &mpp_paths->hash_buckets[hash_idx];
 408
 409        spin_lock(&mpp_paths->hashwlock[hash_idx]);
 410
 411        err = -EEXIST;
 412        hlist_for_each_entry(node, n, bucket, list) {
 413                mpath = node->mpath;
 414                if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
 415                        goto err_exists;
 416        }
 417
 418        hlist_add_head_rcu(&new_node->list, bucket);
 419        if (atomic_inc_return(&mpp_paths->entries) >=
 420                mpp_paths->mean_chain_len * (mpp_paths->hash_mask + 1))
 421                grow = 1;
 422
 423        spin_unlock(&mpp_paths->hashwlock[hash_idx]);
 424        read_unlock(&pathtbl_resize_lock);
 425        if (grow) {
 426                set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
 427                ieee80211_queue_work(&local->hw, &ifmsh->work);
 428        }
 429        return 0;
 430
 431err_exists:
 432        spin_unlock(&mpp_paths->hashwlock[hash_idx]);
 433        read_unlock(&pathtbl_resize_lock);
 434        kfree(new_node);
 435err_node_alloc:
 436        kfree(new_mpath);
 437err_path_alloc:
 438        return err;
 439}
 440
 441
 442/**
 443 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 444 *
 445 * @sta: broken peer link
 446 *
 447 * This function must be called from the rate control algorithm if enough
 448 * delivery errors suggest that a peer link is no longer usable.
 449 */
 450void mesh_plink_broken(struct sta_info *sta)
 451{
 452        struct mesh_path *mpath;
 453        struct mpath_node *node;
 454        struct hlist_node *p;
 455        struct ieee80211_sub_if_data *sdata = sta->sdata;
 456        int i;
 457
 458        rcu_read_lock();
 459        for_each_mesh_entry(mesh_paths, p, node, i) {
 460                mpath = node->mpath;
 461                spin_lock_bh(&mpath->state_lock);
 462                if (mpath->next_hop == sta &&
 463                    mpath->flags & MESH_PATH_ACTIVE &&
 464                    !(mpath->flags & MESH_PATH_FIXED)) {
 465                        mpath->flags &= ~MESH_PATH_ACTIVE;
 466                        ++mpath->dsn;
 467                        spin_unlock_bh(&mpath->state_lock);
 468                        mesh_path_error_tx(mpath->dst,
 469                                        cpu_to_le32(mpath->dsn),
 470                                        sdata->dev->broadcast, sdata);
 471                } else
 472                spin_unlock_bh(&mpath->state_lock);
 473        }
 474        rcu_read_unlock();
 475}
 476
 477/**
 478 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 479 *
 480 * @sta - mesh peer to match
 481 *
 482 * RCU notes: this function is called when a mesh plink transitions from
 483 * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 484 * allows path creation. This will happen before the sta can be freed (because
 485 * sta_info_destroy() calls this) so any reader in a rcu read block will be
 486 * protected against the plink disappearing.
 487 */
 488void mesh_path_flush_by_nexthop(struct sta_info *sta)
 489{
 490        struct mesh_path *mpath;
 491        struct mpath_node *node;
 492        struct hlist_node *p;
 493        int i;
 494
 495        for_each_mesh_entry(mesh_paths, p, node, i) {
 496                mpath = node->mpath;
 497                if (mpath->next_hop == sta)
 498                        mesh_path_del(mpath->dst, mpath->sdata);
 499        }
 500}
 501
 502void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
 503{
 504        struct mesh_path *mpath;
 505        struct mpath_node *node;
 506        struct hlist_node *p;
 507        int i;
 508
 509        for_each_mesh_entry(mesh_paths, p, node, i) {
 510                mpath = node->mpath;
 511                if (mpath->sdata == sdata)
 512                        mesh_path_del(mpath->dst, mpath->sdata);
 513        }
 514}
 515
 516static void mesh_path_node_reclaim(struct rcu_head *rp)
 517{
 518        struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
 519        struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
 520
 521        del_timer_sync(&node->mpath->timer);
 522        atomic_dec(&sdata->u.mesh.mpaths);
 523        kfree(node->mpath);
 524        kfree(node);
 525}
 526
 527/**
 528 * mesh_path_del - delete a mesh path from the table
 529 *
 530 * @addr: dst address (ETH_ALEN length)
 531 * @sdata: local subif
 532 *
 533 * Returns: 0 if succesful
 534 */
 535int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
 536{
 537        struct mesh_path *mpath;
 538        struct mpath_node *node;
 539        struct hlist_head *bucket;
 540        struct hlist_node *n;
 541        int hash_idx;
 542        int err = 0;
 543
 544        read_lock(&pathtbl_resize_lock);
 545        hash_idx = mesh_table_hash(addr, sdata, mesh_paths);
 546        bucket = &mesh_paths->hash_buckets[hash_idx];
 547
 548        spin_lock(&mesh_paths->hashwlock[hash_idx]);
 549        hlist_for_each_entry(node, n, bucket, list) {
 550                mpath = node->mpath;
 551                if (mpath->sdata == sdata &&
 552                                memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
 553                        spin_lock_bh(&mpath->state_lock);
 554                        mpath->flags |= MESH_PATH_RESOLVING;
 555                        hlist_del_rcu(&node->list);
 556                        call_rcu(&node->rcu, mesh_path_node_reclaim);
 557                        atomic_dec(&mesh_paths->entries);
 558                        spin_unlock_bh(&mpath->state_lock);
 559                        goto enddel;
 560                }
 561        }
 562
 563        err = -ENXIO;
 564enddel:
 565        mesh_paths_generation++;
 566        spin_unlock(&mesh_paths->hashwlock[hash_idx]);
 567        read_unlock(&pathtbl_resize_lock);
 568        return err;
 569}
 570
 571/**
 572 * mesh_path_tx_pending - sends pending frames in a mesh path queue
 573 *
 574 * @mpath: mesh path to activate
 575 *
 576 * Locking: the state_lock of the mpath structure must NOT be held when calling
 577 * this function.
 578 */
 579void mesh_path_tx_pending(struct mesh_path *mpath)
 580{
 581        if (mpath->flags & MESH_PATH_ACTIVE)
 582                ieee80211_add_pending_skbs(mpath->sdata->local,
 583                                &mpath->frame_queue);
 584}
 585
 586/**
 587 * mesh_path_discard_frame - discard a frame whose path could not be resolved
 588 *
 589 * @skb: frame to discard
 590 * @sdata: network subif the frame was to be sent through
 591 *
 592 * If the frame was being forwarded from another MP, a PERR frame will be sent
 593 * to the precursor.  The precursor's address (i.e. the previous hop) was saved
 594 * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
 595 * the destination is successfully resolved.
 596 *
 597 * Locking: the function must me called within a rcu_read_lock region
 598 */
 599void mesh_path_discard_frame(struct sk_buff *skb,
 600                             struct ieee80211_sub_if_data *sdata)
 601{
 602        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 603        struct mesh_path *mpath;
 604        u32 dsn = 0;
 605
 606        if (memcmp(hdr->addr4, sdata->dev->dev_addr, ETH_ALEN) != 0) {
 607                u8 *ra, *da;
 608
 609                da = hdr->addr3;
 610                ra = hdr->addr1;
 611                mpath = mesh_path_lookup(da, sdata);
 612                if (mpath)
 613                        dsn = ++mpath->dsn;
 614                mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, sdata);
 615        }
 616
 617        kfree_skb(skb);
 618        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 619}
 620
 621/**
 622 * mesh_path_flush_pending - free the pending queue of a mesh path
 623 *
 624 * @mpath: mesh path whose queue has to be freed
 625 *
 626 * Locking: the function must me called withing a rcu_read_lock region
 627 */
 628void mesh_path_flush_pending(struct mesh_path *mpath)
 629{
 630        struct sk_buff *skb;
 631
 632        while ((skb = skb_dequeue(&mpath->frame_queue)) &&
 633                        (mpath->flags & MESH_PATH_ACTIVE))
 634                mesh_path_discard_frame(skb, mpath->sdata);
 635}
 636
 637/**
 638 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 639 *
 640 * @mpath: the mesh path to modify
 641 * @next_hop: the next hop to force
 642 *
 643 * Locking: this function must be called holding mpath->state_lock
 644 */
 645void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 646{
 647        spin_lock_bh(&mpath->state_lock);
 648        mesh_path_assign_nexthop(mpath, next_hop);
 649        mpath->dsn = 0xffff;
 650        mpath->metric = 0;
 651        mpath->hop_count = 0;
 652        mpath->exp_time = 0;
 653        mpath->flags |= MESH_PATH_FIXED;
 654        mesh_path_activate(mpath);
 655        spin_unlock_bh(&mpath->state_lock);
 656        mesh_path_tx_pending(mpath);
 657}
 658
 659static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
 660{
 661        struct mesh_path *mpath;
 662        struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
 663        mpath = node->mpath;
 664        hlist_del_rcu(p);
 665        if (free_leafs)
 666                kfree(mpath);
 667        kfree(node);
 668}
 669
 670static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
 671{
 672        struct mesh_path *mpath;
 673        struct mpath_node *node, *new_node;
 674        u32 hash_idx;
 675
 676        new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
 677        if (new_node == NULL)
 678                return -ENOMEM;
 679
 680        node = hlist_entry(p, struct mpath_node, list);
 681        mpath = node->mpath;
 682        new_node->mpath = mpath;
 683        hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
 684        hlist_add_head(&new_node->list,
 685                        &newtbl->hash_buckets[hash_idx]);
 686        return 0;
 687}
 688
 689int mesh_pathtbl_init(void)
 690{
 691        mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 692        if (!mesh_paths)
 693                return -ENOMEM;
 694        mesh_paths->free_node = &mesh_path_node_free;
 695        mesh_paths->copy_node = &mesh_path_node_copy;
 696        mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
 697
 698        mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
 699        if (!mpp_paths) {
 700                mesh_table_free(mesh_paths, true);
 701                return -ENOMEM;
 702        }
 703        mpp_paths->free_node = &mesh_path_node_free;
 704        mpp_paths->copy_node = &mesh_path_node_copy;
 705        mpp_paths->mean_chain_len = MEAN_CHAIN_LEN;
 706
 707        return 0;
 708}
 709
 710void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 711{
 712        struct mesh_path *mpath;
 713        struct mpath_node *node;
 714        struct hlist_node *p;
 715        int i;
 716
 717        read_lock(&pathtbl_resize_lock);
 718        for_each_mesh_entry(mesh_paths, p, node, i) {
 719                if (node->mpath->sdata != sdata)
 720                        continue;
 721                mpath = node->mpath;
 722                spin_lock_bh(&mpath->state_lock);
 723                if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 724                    (!(mpath->flags & MESH_PATH_FIXED)) &&
 725                        time_after(jiffies,
 726                         mpath->exp_time + MESH_PATH_EXPIRE)) {
 727                        spin_unlock_bh(&mpath->state_lock);
 728                        mesh_path_del(mpath->dst, mpath->sdata);
 729                } else
 730                        spin_unlock_bh(&mpath->state_lock);
 731        }
 732        read_unlock(&pathtbl_resize_lock);
 733}
 734
 735void mesh_pathtbl_unregister(void)
 736{
 737        mesh_table_free(mesh_paths, true);
 738        mesh_table_free(mpp_paths, true);
 739}
 740