linux/net/mac80211/mesh_pathtbl.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2008, 2009 open80211s Ltd.
   4 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   5 */
   6
   7#include <linux/etherdevice.h>
   8#include <linux/list.h>
   9#include <linux/random.h>
  10#include <linux/slab.h>
  11#include <linux/spinlock.h>
  12#include <linux/string.h>
  13#include <net/mac80211.h>
  14#include "wme.h"
  15#include "ieee80211_i.h"
  16#include "mesh.h"
  17
  18static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
  19
  20static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
  21{
  22        /* Use last four bytes of hw addr as hash index */
  23        return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
  24}
  25
  26static const struct rhashtable_params mesh_rht_params = {
  27        .nelem_hint = 2,
  28        .automatic_shrinking = true,
  29        .key_len = ETH_ALEN,
  30        .key_offset = offsetof(struct mesh_path, dst),
  31        .head_offset = offsetof(struct mesh_path, rhash),
  32        .hashfn = mesh_table_hash,
  33};
  34
  35static inline bool mpath_expired(struct mesh_path *mpath)
  36{
  37        return (mpath->flags & MESH_PATH_ACTIVE) &&
  38               time_after(jiffies, mpath->exp_time) &&
  39               !(mpath->flags & MESH_PATH_FIXED);
  40}
  41
  42static void mesh_path_rht_free(void *ptr, void *tblptr)
  43{
  44        struct mesh_path *mpath = ptr;
  45        struct mesh_table *tbl = tblptr;
  46
  47        mesh_path_free_rcu(tbl, mpath);
  48}
  49
  50static struct mesh_table *mesh_table_alloc(void)
  51{
  52        struct mesh_table *newtbl;
  53
  54        newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
  55        if (!newtbl)
  56                return NULL;
  57
  58        INIT_HLIST_HEAD(&newtbl->known_gates);
  59        INIT_HLIST_HEAD(&newtbl->walk_head);
  60        atomic_set(&newtbl->entries,  0);
  61        spin_lock_init(&newtbl->gates_lock);
  62        spin_lock_init(&newtbl->walk_lock);
  63        rhashtable_init(&newtbl->rhead, &mesh_rht_params);
  64
  65        return newtbl;
  66}
  67
  68static void mesh_table_free(struct mesh_table *tbl)
  69{
  70        rhashtable_free_and_destroy(&tbl->rhead,
  71                                    mesh_path_rht_free, tbl);
  72        kfree(tbl);
  73}
  74
  75/**
  76 * mesh_path_assign_nexthop - update mesh path next hop
  77 *
  78 * @mpath: mesh path to update
  79 * @sta: next hop to assign
  80 *
  81 * Locking: mpath->state_lock must be held when calling this function
  82 */
  83void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
  84{
  85        struct sk_buff *skb;
  86        struct ieee80211_hdr *hdr;
  87        unsigned long flags;
  88
  89        rcu_assign_pointer(mpath->next_hop, sta);
  90
  91        spin_lock_irqsave(&mpath->frame_queue.lock, flags);
  92        skb_queue_walk(&mpath->frame_queue, skb) {
  93                hdr = (struct ieee80211_hdr *) skb->data;
  94                memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
  95                memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
  96                ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
  97        }
  98
  99        spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 100}
 101
 102static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 103                             struct mesh_path *gate_mpath)
 104{
 105        struct ieee80211_hdr *hdr;
 106        struct ieee80211s_hdr *mshdr;
 107        int mesh_hdrlen, hdrlen;
 108        char *next_hop;
 109
 110        hdr = (struct ieee80211_hdr *) skb->data;
 111        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 112        mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 113
 114        if (!(mshdr->flags & MESH_FLAGS_AE)) {
 115                /* size of the fixed part of the mesh header */
 116                mesh_hdrlen = 6;
 117
 118                /* make room for the two extended addresses */
 119                skb_push(skb, 2 * ETH_ALEN);
 120                memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 121
 122                hdr = (struct ieee80211_hdr *) skb->data;
 123
 124                /* we preserve the previous mesh header and only add
 125                 * the new addresses */
 126                mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 127                mshdr->flags = MESH_FLAGS_AE_A5_A6;
 128                memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 129                memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 130        }
 131
 132        /* update next hop */
 133        hdr = (struct ieee80211_hdr *) skb->data;
 134        rcu_read_lock();
 135        next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 136        memcpy(hdr->addr1, next_hop, ETH_ALEN);
 137        rcu_read_unlock();
 138        memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 139        memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 140}
 141
 142/**
 143 * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 144 *
 145 * This function is used to transfer or copy frames from an unresolved mpath to
 146 * a gate mpath.  The function also adds the Address Extension field and
 147 * updates the next hop.
 148 *
 149 * If a frame already has an Address Extension field, only the next hop and
 150 * destination addresses are updated.
 151 *
 152 * The gate mpath must be an active mpath with a valid mpath->next_hop.
 153 *
 154 * @gate_mpath: An active mpath the frames will be sent to (i.e. the gate)
 155 * @from_mpath: The failed mpath
 156 * @copy: When true, copy all the frames to the new mpath queue.  When false,
 157 * move them.
 158 */
 159static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 160                                    struct mesh_path *from_mpath,
 161                                    bool copy)
 162{
 163        struct sk_buff *skb, *fskb, *tmp;
 164        struct sk_buff_head failq;
 165        unsigned long flags;
 166
 167        if (WARN_ON(gate_mpath == from_mpath))
 168                return;
 169        if (WARN_ON(!gate_mpath->next_hop))
 170                return;
 171
 172        __skb_queue_head_init(&failq);
 173
 174        spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 175        skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 176        spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 177
 178        skb_queue_walk_safe(&failq, fskb, tmp) {
 179                if (skb_queue_len(&gate_mpath->frame_queue) >=
 180                                  MESH_FRAME_QUEUE_LEN) {
 181                        mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 182                        break;
 183                }
 184
 185                skb = skb_copy(fskb, GFP_ATOMIC);
 186                if (WARN_ON(!skb))
 187                        break;
 188
 189                prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 190                skb_queue_tail(&gate_mpath->frame_queue, skb);
 191
 192                if (copy)
 193                        continue;
 194
 195                __skb_unlink(fskb, &failq);
 196                kfree_skb(fskb);
 197        }
 198
 199        mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 200                  gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 201
 202        if (!copy)
 203                return;
 204
 205        spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 206        skb_queue_splice(&failq, &from_mpath->frame_queue);
 207        spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 208}
 209
 210
 211static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 212                                      struct ieee80211_sub_if_data *sdata)
 213{
 214        struct mesh_path *mpath;
 215
 216        mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
 217
 218        if (mpath && mpath_expired(mpath)) {
 219                spin_lock_bh(&mpath->state_lock);
 220                mpath->flags &= ~MESH_PATH_ACTIVE;
 221                spin_unlock_bh(&mpath->state_lock);
 222        }
 223        return mpath;
 224}
 225
 226/**
 227 * mesh_path_lookup - look up a path in the mesh path table
 228 * @sdata: local subif
 229 * @dst: hardware address (ETH_ALEN length) of destination
 230 *
 231 * Returns: pointer to the mesh path structure, or NULL if not found
 232 *
 233 * Locking: must be called within a read rcu section.
 234 */
 235struct mesh_path *
 236mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 237{
 238        return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
 239}
 240
 241struct mesh_path *
 242mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 243{
 244        return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
 245}
 246
 247static struct mesh_path *
 248__mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
 249{
 250        int i = 0;
 251        struct mesh_path *mpath;
 252
 253        hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 254                if (i++ == idx)
 255                        break;
 256        }
 257
 258        if (!mpath)
 259                return NULL;
 260
 261        if (mpath_expired(mpath)) {
 262                spin_lock_bh(&mpath->state_lock);
 263                mpath->flags &= ~MESH_PATH_ACTIVE;
 264                spin_unlock_bh(&mpath->state_lock);
 265        }
 266        return mpath;
 267}
 268
 269/**
 270 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 271 * @idx: index
 272 * @sdata: local subif, or NULL for all entries
 273 *
 274 * Returns: pointer to the mesh path structure, or NULL if not found.
 275 *
 276 * Locking: must be called within a read rcu section.
 277 */
 278struct mesh_path *
 279mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 280{
 281        return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
 282}
 283
 284/**
 285 * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 286 * @idx: index
 287 * @sdata: local subif, or NULL for all entries
 288 *
 289 * Returns: pointer to the proxy path structure, or NULL if not found.
 290 *
 291 * Locking: must be called within a read rcu section.
 292 */
 293struct mesh_path *
 294mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 295{
 296        return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
 297}
 298
 299/**
 300 * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 301 * @mpath: gate path to add to table
 302 */
 303int mesh_path_add_gate(struct mesh_path *mpath)
 304{
 305        struct mesh_table *tbl;
 306        int err;
 307
 308        rcu_read_lock();
 309        tbl = mpath->sdata->u.mesh.mesh_paths;
 310
 311        spin_lock_bh(&mpath->state_lock);
 312        if (mpath->is_gate) {
 313                err = -EEXIST;
 314                spin_unlock_bh(&mpath->state_lock);
 315                goto err_rcu;
 316        }
 317        mpath->is_gate = true;
 318        mpath->sdata->u.mesh.num_gates++;
 319
 320        spin_lock(&tbl->gates_lock);
 321        hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
 322        spin_unlock(&tbl->gates_lock);
 323
 324        spin_unlock_bh(&mpath->state_lock);
 325
 326        mpath_dbg(mpath->sdata,
 327                  "Mesh path: Recorded new gate: %pM. %d known gates\n",
 328                  mpath->dst, mpath->sdata->u.mesh.num_gates);
 329        err = 0;
 330err_rcu:
 331        rcu_read_unlock();
 332        return err;
 333}
 334
 335/**
 336 * mesh_gate_del - remove a mesh gate from the list of known gates
 337 * @tbl: table which holds our list of known gates
 338 * @mpath: gate mpath
 339 */
 340static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 341{
 342        lockdep_assert_held(&mpath->state_lock);
 343        if (!mpath->is_gate)
 344                return;
 345
 346        mpath->is_gate = false;
 347        spin_lock_bh(&tbl->gates_lock);
 348        hlist_del_rcu(&mpath->gate_list);
 349        mpath->sdata->u.mesh.num_gates--;
 350        spin_unlock_bh(&tbl->gates_lock);
 351
 352        mpath_dbg(mpath->sdata,
 353                  "Mesh path: Deleted gate: %pM. %d known gates\n",
 354                  mpath->dst, mpath->sdata->u.mesh.num_gates);
 355}
 356
 357/**
 358 * mesh_gate_num - number of gates known to this interface
 359 * @sdata: subif data
 360 */
 361int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 362{
 363        return sdata->u.mesh.num_gates;
 364}
 365
 366static
 367struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
 368                                const u8 *dst, gfp_t gfp_flags)
 369{
 370        struct mesh_path *new_mpath;
 371
 372        new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
 373        if (!new_mpath)
 374                return NULL;
 375
 376        memcpy(new_mpath->dst, dst, ETH_ALEN);
 377        eth_broadcast_addr(new_mpath->rann_snd_addr);
 378        new_mpath->is_root = false;
 379        new_mpath->sdata = sdata;
 380        new_mpath->flags = 0;
 381        skb_queue_head_init(&new_mpath->frame_queue);
 382        new_mpath->exp_time = jiffies;
 383        spin_lock_init(&new_mpath->state_lock);
 384        timer_setup(&new_mpath->timer, mesh_path_timer, 0);
 385
 386        return new_mpath;
 387}
 388
 389/**
 390 * mesh_path_add - allocate and add a new path to the mesh path table
 391 * @dst: destination address of the path (ETH_ALEN length)
 392 * @sdata: local subif
 393 *
 394 * Returns: 0 on success
 395 *
 396 * State: the initial state of the new path is set to 0
 397 */
 398struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 399                                const u8 *dst)
 400{
 401        struct mesh_table *tbl;
 402        struct mesh_path *mpath, *new_mpath;
 403
 404        if (ether_addr_equal(dst, sdata->vif.addr))
 405                /* never add ourselves as neighbours */
 406                return ERR_PTR(-ENOTSUPP);
 407
 408        if (is_multicast_ether_addr(dst))
 409                return ERR_PTR(-ENOTSUPP);
 410
 411        if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 412                return ERR_PTR(-ENOSPC);
 413
 414        new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 415        if (!new_mpath)
 416                return ERR_PTR(-ENOMEM);
 417
 418        tbl = sdata->u.mesh.mesh_paths;
 419        spin_lock_bh(&tbl->walk_lock);
 420        mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
 421                                                  &new_mpath->rhash,
 422                                                  mesh_rht_params);
 423        if (!mpath)
 424                hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
 425        spin_unlock_bh(&tbl->walk_lock);
 426
 427        if (mpath) {
 428                kfree(new_mpath);
 429
 430                if (IS_ERR(mpath))
 431                        return mpath;
 432
 433                new_mpath = mpath;
 434        }
 435
 436        sdata->u.mesh.mesh_paths_generation++;
 437        return new_mpath;
 438}
 439
 440int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 441                 const u8 *dst, const u8 *mpp)
 442{
 443        struct mesh_table *tbl;
 444        struct mesh_path *new_mpath;
 445        int ret;
 446
 447        if (ether_addr_equal(dst, sdata->vif.addr))
 448                /* never add ourselves as neighbours */
 449                return -ENOTSUPP;
 450
 451        if (is_multicast_ether_addr(dst))
 452                return -ENOTSUPP;
 453
 454        new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 455
 456        if (!new_mpath)
 457                return -ENOMEM;
 458
 459        memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 460        tbl = sdata->u.mesh.mpp_paths;
 461
 462        spin_lock_bh(&tbl->walk_lock);
 463        ret = rhashtable_lookup_insert_fast(&tbl->rhead,
 464                                            &new_mpath->rhash,
 465                                            mesh_rht_params);
 466        if (!ret)
 467                hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
 468        spin_unlock_bh(&tbl->walk_lock);
 469
 470        if (ret)
 471                kfree(new_mpath);
 472
 473        sdata->u.mesh.mpp_paths_generation++;
 474        return ret;
 475}
 476
 477
 478/**
 479 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 480 *
 481 * @sta: broken peer link
 482 *
 483 * This function must be called from the rate control algorithm if enough
 484 * delivery errors suggest that a peer link is no longer usable.
 485 */
 486void mesh_plink_broken(struct sta_info *sta)
 487{
 488        struct ieee80211_sub_if_data *sdata = sta->sdata;
 489        struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
 490        static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 491        struct mesh_path *mpath;
 492
 493        rcu_read_lock();
 494        hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 495                if (rcu_access_pointer(mpath->next_hop) == sta &&
 496                    mpath->flags & MESH_PATH_ACTIVE &&
 497                    !(mpath->flags & MESH_PATH_FIXED)) {
 498                        spin_lock_bh(&mpath->state_lock);
 499                        mpath->flags &= ~MESH_PATH_ACTIVE;
 500                        ++mpath->sn;
 501                        spin_unlock_bh(&mpath->state_lock);
 502                        mesh_path_error_tx(sdata,
 503                                sdata->u.mesh.mshcfg.element_ttl,
 504                                mpath->dst, mpath->sn,
 505                                WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 506                }
 507        }
 508        rcu_read_unlock();
 509}
 510
 511static void mesh_path_free_rcu(struct mesh_table *tbl,
 512                               struct mesh_path *mpath)
 513{
 514        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 515
 516        spin_lock_bh(&mpath->state_lock);
 517        mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
 518        mesh_gate_del(tbl, mpath);
 519        spin_unlock_bh(&mpath->state_lock);
 520        del_timer_sync(&mpath->timer);
 521        atomic_dec(&sdata->u.mesh.mpaths);
 522        atomic_dec(&tbl->entries);
 523        mesh_path_flush_pending(mpath);
 524        kfree_rcu(mpath, rcu);
 525}
 526
 527static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
 528{
 529        hlist_del_rcu(&mpath->walk_list);
 530        rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
 531        mesh_path_free_rcu(tbl, mpath);
 532}
 533
 534/**
 535 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 536 *
 537 * @sta: mesh peer to match
 538 *
 539 * RCU notes: this function is called when a mesh plink transitions from
 540 * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 541 * allows path creation. This will happen before the sta can be freed (because
 542 * sta_info_destroy() calls this) so any reader in a rcu read block will be
 543 * protected against the plink disappearing.
 544 */
 545void mesh_path_flush_by_nexthop(struct sta_info *sta)
 546{
 547        struct ieee80211_sub_if_data *sdata = sta->sdata;
 548        struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
 549        struct mesh_path *mpath;
 550        struct hlist_node *n;
 551
 552        spin_lock_bh(&tbl->walk_lock);
 553        hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 554                if (rcu_access_pointer(mpath->next_hop) == sta)
 555                        __mesh_path_del(tbl, mpath);
 556        }
 557        spin_unlock_bh(&tbl->walk_lock);
 558}
 559
 560static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
 561                               const u8 *proxy)
 562{
 563        struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
 564        struct mesh_path *mpath;
 565        struct hlist_node *n;
 566
 567        spin_lock_bh(&tbl->walk_lock);
 568        hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 569                if (ether_addr_equal(mpath->mpp, proxy))
 570                        __mesh_path_del(tbl, mpath);
 571        }
 572        spin_unlock_bh(&tbl->walk_lock);
 573}
 574
 575static void table_flush_by_iface(struct mesh_table *tbl)
 576{
 577        struct mesh_path *mpath;
 578        struct hlist_node *n;
 579
 580        spin_lock_bh(&tbl->walk_lock);
 581        hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 582                __mesh_path_del(tbl, mpath);
 583        }
 584        spin_unlock_bh(&tbl->walk_lock);
 585}
 586
 587/**
 588 * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 589 *
 590 * This function deletes both mesh paths as well as mesh portal paths.
 591 *
 592 * @sdata: interface data to match
 593 *
 594 */
 595void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 596{
 597        table_flush_by_iface(sdata->u.mesh.mesh_paths);
 598        table_flush_by_iface(sdata->u.mesh.mpp_paths);
 599}
 600
 601/**
 602 * table_path_del - delete a path from the mesh or mpp table
 603 *
 604 * @tbl: mesh or mpp path table
 605 * @sdata: local subif
 606 * @addr: dst address (ETH_ALEN length)
 607 *
 608 * Returns: 0 if successful
 609 */
 610static int table_path_del(struct mesh_table *tbl,
 611                          struct ieee80211_sub_if_data *sdata,
 612                          const u8 *addr)
 613{
 614        struct mesh_path *mpath;
 615
 616        spin_lock_bh(&tbl->walk_lock);
 617        mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
 618        if (!mpath) {
 619                spin_unlock_bh(&tbl->walk_lock);
 620                return -ENXIO;
 621        }
 622
 623        __mesh_path_del(tbl, mpath);
 624        spin_unlock_bh(&tbl->walk_lock);
 625        return 0;
 626}
 627
 628
 629/**
 630 * mesh_path_del - delete a mesh path from the table
 631 *
 632 * @addr: dst address (ETH_ALEN length)
 633 * @sdata: local subif
 634 *
 635 * Returns: 0 if successful
 636 */
 637int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 638{
 639        int err;
 640
 641        /* flush relevant mpp entries first */
 642        mpp_flush_by_proxy(sdata, addr);
 643
 644        err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
 645        sdata->u.mesh.mesh_paths_generation++;
 646        return err;
 647}
 648
 649/**
 650 * mesh_path_tx_pending - sends pending frames in a mesh path queue
 651 *
 652 * @mpath: mesh path to activate
 653 *
 654 * Locking: the state_lock of the mpath structure must NOT be held when calling
 655 * this function.
 656 */
 657void mesh_path_tx_pending(struct mesh_path *mpath)
 658{
 659        if (mpath->flags & MESH_PATH_ACTIVE)
 660                ieee80211_add_pending_skbs(mpath->sdata->local,
 661                                &mpath->frame_queue);
 662}
 663
 664/**
 665 * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 666 *
 667 * @mpath: mesh path whose queue will be emptied
 668 *
 669 * If there is only one gate, the frames are transferred from the failed mpath
 670 * queue to that gate's queue.  If there are more than one gates, the frames
 671 * are copied from each gate to the next.  After frames are copied, the
 672 * mpath queues are emptied onto the transmission queue.
 673 */
 674int mesh_path_send_to_gates(struct mesh_path *mpath)
 675{
 676        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 677        struct mesh_table *tbl;
 678        struct mesh_path *from_mpath = mpath;
 679        struct mesh_path *gate;
 680        bool copy = false;
 681
 682        tbl = sdata->u.mesh.mesh_paths;
 683
 684        rcu_read_lock();
 685        hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 686                if (gate->flags & MESH_PATH_ACTIVE) {
 687                        mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
 688                        mesh_path_move_to_queue(gate, from_mpath, copy);
 689                        from_mpath = gate;
 690                        copy = true;
 691                } else {
 692                        mpath_dbg(sdata,
 693                                  "Not forwarding to %pM (flags %#x)\n",
 694                                  gate->dst, gate->flags);
 695                }
 696        }
 697
 698        hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 699                mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
 700                mesh_path_tx_pending(gate);
 701        }
 702        rcu_read_unlock();
 703
 704        return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 705}
 706
 707/**
 708 * mesh_path_discard_frame - discard a frame whose path could not be resolved
 709 *
 710 * @skb: frame to discard
 711 * @sdata: network subif the frame was to be sent through
 712 *
 713 * Locking: the function must me called within a rcu_read_lock region
 714 */
 715void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 716                             struct sk_buff *skb)
 717{
 718        kfree_skb(skb);
 719        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 720}
 721
 722/**
 723 * mesh_path_flush_pending - free the pending queue of a mesh path
 724 *
 725 * @mpath: mesh path whose queue has to be freed
 726 *
 727 * Locking: the function must me called within a rcu_read_lock region
 728 */
 729void mesh_path_flush_pending(struct mesh_path *mpath)
 730{
 731        struct sk_buff *skb;
 732
 733        while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
 734                mesh_path_discard_frame(mpath->sdata, skb);
 735}
 736
 737/**
 738 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 739 *
 740 * @mpath: the mesh path to modify
 741 * @next_hop: the next hop to force
 742 *
 743 * Locking: this function must be called holding mpath->state_lock
 744 */
 745void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 746{
 747        spin_lock_bh(&mpath->state_lock);
 748        mesh_path_assign_nexthop(mpath, next_hop);
 749        mpath->sn = 0xffff;
 750        mpath->metric = 0;
 751        mpath->hop_count = 0;
 752        mpath->exp_time = 0;
 753        mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
 754        mesh_path_activate(mpath);
 755        spin_unlock_bh(&mpath->state_lock);
 756        ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
 757        /* init it at a low value - 0 start is tricky */
 758        ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
 759        mesh_path_tx_pending(mpath);
 760}
 761
 762int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
 763{
 764        struct mesh_table *tbl_path, *tbl_mpp;
 765        int ret;
 766
 767        tbl_path = mesh_table_alloc();
 768        if (!tbl_path)
 769                return -ENOMEM;
 770
 771        tbl_mpp = mesh_table_alloc();
 772        if (!tbl_mpp) {
 773                ret = -ENOMEM;
 774                goto free_path;
 775        }
 776
 777        sdata->u.mesh.mesh_paths = tbl_path;
 778        sdata->u.mesh.mpp_paths = tbl_mpp;
 779
 780        return 0;
 781
 782free_path:
 783        mesh_table_free(tbl_path);
 784        return ret;
 785}
 786
 787static
 788void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
 789                          struct mesh_table *tbl)
 790{
 791        struct mesh_path *mpath;
 792        struct hlist_node *n;
 793
 794        spin_lock_bh(&tbl->walk_lock);
 795        hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 796                if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 797                    (!(mpath->flags & MESH_PATH_FIXED)) &&
 798                     time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
 799                        __mesh_path_del(tbl, mpath);
 800        }
 801        spin_unlock_bh(&tbl->walk_lock);
 802}
 803
 804void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 805{
 806        mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
 807        mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
 808}
 809
 810void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
 811{
 812        mesh_table_free(sdata->u.mesh.mesh_paths);
 813        mesh_table_free(sdata->u.mesh.mpp_paths);
 814}
 815