root/net/mac80211/mesh_pathtbl.c

DEFINITIONS

1. mesh_table_hash
2. mpath_expired
3. mesh_path_rht_free
4. mesh_table_alloc
5. mesh_table_free
6. mesh_path_assign_nexthop
7. prepare_for_gate
8. mesh_path_move_to_queue
9. mpath_lookup
10. mesh_path_lookup
11. mpp_path_lookup
12. __mesh_path_lookup_by_idx
13. mesh_path_lookup_by_idx
14. mpp_path_lookup_by_idx
15. mesh_path_add_gate
16. mesh_gate_del
17. mesh_gate_num
18. mesh_path_new
19. mesh_path_add
20. mpp_path_add
21. mesh_plink_broken
22. mesh_path_free_rcu
23. __mesh_path_del
24. mesh_path_flush_by_nexthop
25. mpp_flush_by_proxy
26. table_flush_by_iface
27. mesh_path_flush_by_iface
28. table_path_del
29. mesh_path_del
30. mesh_path_tx_pending
31. mesh_path_send_to_gates
32. mesh_path_discard_frame
33. mesh_path_flush_pending
34. mesh_path_fix_nexthop
35. mesh_pathtbl_init
36. mesh_path_tbl_expire
37. mesh_path_expire
38. mesh_pathtbl_unregister

   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 
  18 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
  19 
  20 static 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 
  26 static 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 
  35 static 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 
  42 static 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 
  50 static 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 
  64         return newtbl;
  65 }
  66 
  67 static void mesh_table_free(struct mesh_table *tbl)
  68 {
  69         rhashtable_free_and_destroy(&tbl->rhead,
  70                                     mesh_path_rht_free, tbl);
  71         kfree(tbl);
  72 }
  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  */
  83 void 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 
 102 static 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 addreses */
 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  *
 144  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 145  *
 146  * This function is used to transfer or copy frames from an unresolved mpath to
 147  * a gate mpath.  The function also adds the Address Extension field and
 148  * updates the next hop.
 149  *
 150  * If a frame already has an Address Extension field, only the next hop and
 151  * destination addresses are updated.
 152  *
 153  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 154  *
 155  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 156  * @from_mpath: The failed mpath
 157  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 158  * move them.
 159  */
 160 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 161                                     struct mesh_path *from_mpath,
 162                                     bool copy)
 163 {
 164         struct sk_buff *skb, *fskb, *tmp;
 165         struct sk_buff_head failq;
 166         unsigned long flags;
 167 
 168         if (WARN_ON(gate_mpath == from_mpath))
 169                 return;
 170         if (WARN_ON(!gate_mpath->next_hop))
 171                 return;
 172 
 173         __skb_queue_head_init(&failq);
 174 
 175         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 176         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 177         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 178 
 179         skb_queue_walk_safe(&failq, fskb, tmp) {
 180                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 181                                   MESH_FRAME_QUEUE_LEN) {
 182                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 183                         break;
 184                 }
 185 
 186                 skb = skb_copy(fskb, GFP_ATOMIC);
 187                 if (WARN_ON(!skb))
 188                         break;
 189 
 190                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 191                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 192 
 193                 if (copy)
 194                         continue;
 195 
 196                 __skb_unlink(fskb, &failq);
 197                 kfree_skb(fskb);
 198         }
 199 
 200         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 201                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 202 
 203         if (!copy)
 204                 return;
 205 
 206         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 207         skb_queue_splice(&failq, &from_mpath->frame_queue);
 208         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 209 }
 210 
 211 
 212 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 213                                       struct ieee80211_sub_if_data *sdata)
 214 {
 215         struct mesh_path *mpath;
 216 
 217         mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
 218 
 219         if (mpath && mpath_expired(mpath)) {
 220                 spin_lock_bh(&mpath->state_lock);
 221                 mpath->flags &= ~MESH_PATH_ACTIVE;
 222                 spin_unlock_bh(&mpath->state_lock);
 223         }
 224         return mpath;
 225 }
 226 
 227 /**
 228  * mesh_path_lookup - look up a path in the mesh path table
 229  * @sdata: local subif
 230  * @dst: hardware address (ETH_ALEN length) of destination
 231  *
 232  * Returns: pointer to the mesh path structure, or NULL if not found
 233  *
 234  * Locking: must be called within a read rcu section.
 235  */
 236 struct mesh_path *
 237 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 238 {
 239         return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
 240 }
 241 
 242 struct mesh_path *
 243 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 244 {
 245         return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
 246 }
 247 
 248 static struct mesh_path *
 249 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
 250 {
 251         int i = 0;
 252         struct mesh_path *mpath;
 253 
 254         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 255                 if (i++ == idx)
 256                         break;
 257         }
 258 
 259         if (!mpath)
 260                 return NULL;
 261 
 262         if (mpath_expired(mpath)) {
 263                 spin_lock_bh(&mpath->state_lock);
 264                 mpath->flags &= ~MESH_PATH_ACTIVE;
 265                 spin_unlock_bh(&mpath->state_lock);
 266         }
 267         return mpath;
 268 }
 269 
 270 /**
 271  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 272  * @idx: index
 273  * @sdata: local subif, or NULL for all entries
 274  *
 275  * Returns: pointer to the mesh path structure, or NULL if not found.
 276  *
 277  * Locking: must be called within a read rcu section.
 278  */
 279 struct mesh_path *
 280 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 281 {
 282         return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
 283 }
 284 
 285 /**
 286  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 287  * @idx: index
 288  * @sdata: local subif, or NULL for all entries
 289  *
 290  * Returns: pointer to the proxy path structure, or NULL if not found.
 291  *
 292  * Locking: must be called within a read rcu section.
 293  */
 294 struct mesh_path *
 295 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 296 {
 297         return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
 298 }
 299 
 300 /**
 301  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 302  * @mpath: gate path to add to table
 303  */
 304 int mesh_path_add_gate(struct mesh_path *mpath)
 305 {
 306         struct mesh_table *tbl;
 307         int err;
 308 
 309         rcu_read_lock();
 310         tbl = mpath->sdata->u.mesh.mesh_paths;
 311 
 312         spin_lock_bh(&mpath->state_lock);
 313         if (mpath->is_gate) {
 314                 err = -EEXIST;
 315                 spin_unlock_bh(&mpath->state_lock);
 316                 goto err_rcu;
 317         }
 318         mpath->is_gate = true;
 319         mpath->sdata->u.mesh.num_gates++;
 320 
 321         spin_lock(&tbl->gates_lock);
 322         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
 323         spin_unlock(&tbl->gates_lock);
 324 
 325         spin_unlock_bh(&mpath->state_lock);
 326 
 327         mpath_dbg(mpath->sdata,
 328                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 329                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 330         err = 0;
 331 err_rcu:
 332         rcu_read_unlock();
 333         return err;
 334 }
 335 
 336 /**
 337  * mesh_gate_del - remove a mesh gate from the list of known gates
 338  * @tbl: table which holds our list of known gates
 339  * @mpath: gate mpath
 340  */
 341 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 342 {
 343         lockdep_assert_held(&mpath->state_lock);
 344         if (!mpath->is_gate)
 345                 return;
 346 
 347         mpath->is_gate = false;
 348         spin_lock_bh(&tbl->gates_lock);
 349         hlist_del_rcu(&mpath->gate_list);
 350         mpath->sdata->u.mesh.num_gates--;
 351         spin_unlock_bh(&tbl->gates_lock);
 352 
 353         mpath_dbg(mpath->sdata,
 354                   "Mesh path: Deleted gate: %pM. %d known gates\n",
 355                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 356 }
 357 
 358 /**
 359  * mesh_gate_num - number of gates known to this interface
 360  * @sdata: subif data
 361  */
 362 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 363 {
 364         return sdata->u.mesh.num_gates;
 365 }
 366 
 367 static
 368 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
 369                                 const u8 *dst, gfp_t gfp_flags)
 370 {
 371         struct mesh_path *new_mpath;
 372 
 373         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
 374         if (!new_mpath)
 375                 return NULL;
 376 
 377         memcpy(new_mpath->dst, dst, ETH_ALEN);
 378         eth_broadcast_addr(new_mpath->rann_snd_addr);
 379         new_mpath->is_root = false;
 380         new_mpath->sdata = sdata;
 381         new_mpath->flags = 0;
 382         skb_queue_head_init(&new_mpath->frame_queue);
 383         new_mpath->exp_time = jiffies;
 384         spin_lock_init(&new_mpath->state_lock);
 385         timer_setup(&new_mpath->timer, mesh_path_timer, 0);
 386 
 387         return new_mpath;
 388 }
 389 
 390 /**
 391  * mesh_path_add - allocate and add a new path to the mesh path table
 392  * @dst: destination address of the path (ETH_ALEN length)
 393  * @sdata: local subif
 394  *
 395  * Returns: 0 on success
 396  *
 397  * State: the initial state of the new path is set to 0
 398  */
 399 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 400                                 const u8 *dst)
 401 {
 402         struct mesh_table *tbl;
 403         struct mesh_path *mpath, *new_mpath;
 404 
 405         if (ether_addr_equal(dst, sdata->vif.addr))
 406                 /* never add ourselves as neighbours */
 407                 return ERR_PTR(-ENOTSUPP);
 408 
 409         if (is_multicast_ether_addr(dst))
 410                 return ERR_PTR(-ENOTSUPP);
 411 
 412         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 413                 return ERR_PTR(-ENOSPC);
 414 
 415         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 416         if (!new_mpath)
 417                 return ERR_PTR(-ENOMEM);
 418 
 419         tbl = sdata->u.mesh.mesh_paths;
 420         spin_lock_bh(&tbl->walk_lock);
 421         mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
 422                                                   &new_mpath->rhash,
 423                                                   mesh_rht_params);
 424         if (!mpath)
 425                 hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
 426         spin_unlock_bh(&tbl->walk_lock);
 427 
 428         if (mpath) {
 429                 kfree(new_mpath);
 430 
 431                 if (IS_ERR(mpath))
 432                         return mpath;
 433 
 434                 new_mpath = mpath;
 435         }
 436 
 437         sdata->u.mesh.mesh_paths_generation++;
 438         return new_mpath;
 439 }
 440 
 441 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 442                  const u8 *dst, const u8 *mpp)
 443 {
 444         struct mesh_table *tbl;
 445         struct mesh_path *new_mpath;
 446         int ret;
 447 
 448         if (ether_addr_equal(dst, sdata->vif.addr))
 449                 /* never add ourselves as neighbours */
 450                 return -ENOTSUPP;
 451 
 452         if (is_multicast_ether_addr(dst))
 453                 return -ENOTSUPP;
 454 
 455         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 456 
 457         if (!new_mpath)
 458                 return -ENOMEM;
 459 
 460         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 461         tbl = sdata->u.mesh.mpp_paths;
 462 
 463         spin_lock_bh(&tbl->walk_lock);
 464         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
 465                                             &new_mpath->rhash,
 466                                             mesh_rht_params);
 467         if (!ret)
 468                 hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
 469         spin_unlock_bh(&tbl->walk_lock);
 470 
 471         if (ret)
 472                 kfree(new_mpath);
 473 
 474         sdata->u.mesh.mpp_paths_generation++;
 475         return ret;
 476 }
 477 
 478 
 479 /**
 480  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 481  *
 482  * @sta: broken peer link
 483  *
 484  * This function must be called from the rate control algorithm if enough
 485  * delivery errors suggest that a peer link is no longer usable.
 486  */
 487 void mesh_plink_broken(struct sta_info *sta)
 488 {
 489         struct ieee80211_sub_if_data *sdata = sta->sdata;
 490         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
 491         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 492         struct mesh_path *mpath;
 493 
 494         rcu_read_lock();
 495         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 496                 if (rcu_access_pointer(mpath->next_hop) == sta &&
 497                     mpath->flags & MESH_PATH_ACTIVE &&
 498                     !(mpath->flags & MESH_PATH_FIXED)) {
 499                         spin_lock_bh(&mpath->state_lock);
 500                         mpath->flags &= ~MESH_PATH_ACTIVE;
 501                         ++mpath->sn;
 502                         spin_unlock_bh(&mpath->state_lock);
 503                         mesh_path_error_tx(sdata,
 504                                 sdata->u.mesh.mshcfg.element_ttl,
 505                                 mpath->dst, mpath->sn,
 506                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 507                 }
 508         }
 509         rcu_read_unlock();
 510 }
 511 
 512 static void mesh_path_free_rcu(struct mesh_table *tbl,
 513                                struct mesh_path *mpath)
 514 {
 515         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 516 
 517         spin_lock_bh(&mpath->state_lock);
 518         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
 519         mesh_gate_del(tbl, mpath);
 520         spin_unlock_bh(&mpath->state_lock);
 521         del_timer_sync(&mpath->timer);
 522         atomic_dec(&sdata->u.mesh.mpaths);
 523         atomic_dec(&tbl->entries);
 524         kfree_rcu(mpath, rcu);
 525 }
 526 
 527 static 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  */
 545 void 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 
 560 static 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 
 575 static 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  */
 595 void 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  */
 610 static 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  */
 637 int 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  */
 657 void 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  */
 674 int 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  */
 715 void 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  */
 729 void 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  */
 745 void 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 
 762 int 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         rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
 778         rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
 779 
 780         sdata->u.mesh.mesh_paths = tbl_path;
 781         sdata->u.mesh.mpp_paths = tbl_mpp;
 782 
 783         return 0;
 784 
 785 free_path:
 786         mesh_table_free(tbl_path);
 787         return ret;
 788 }
 789 
 790 static
 791 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
 792                           struct mesh_table *tbl)
 793 {
 794         struct mesh_path *mpath;
 795         struct hlist_node *n;
 796 
 797         spin_lock_bh(&tbl->walk_lock);
 798         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 799                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
 800                     (!(mpath->flags & MESH_PATH_FIXED)) &&
 801                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
 802                         __mesh_path_del(tbl, mpath);
 803         }
 804         spin_unlock_bh(&tbl->walk_lock);
 805 }
 806 
 807 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 808 {
 809         mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
 810         mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
 811 }
 812 
 813 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
 814 {
 815         mesh_table_free(sdata->u.mesh.mesh_paths);
 816         mesh_table_free(sdata->u.mesh.mpp_paths);
 817 }