net/mac80211/mesh_pathtbl.c

   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 #include <linux/rhashtable.h>
  18
  19 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
  20
  21 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
  22 {
  23         /* Use last four bytes of hw addr as hash index */
  24         return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
  25 }
  26
  27 static const struct rhashtable_params mesh_rht_params = {
  28         .nelem_hint = 2,
  29         .automatic_shrinking = true,
  30         .key_len = ETH_ALEN,
  31         .key_offset = offsetof(struct mesh_path, dst),
  32         .head_offset = offsetof(struct mesh_path, rhash),
  33         .hashfn = mesh_table_hash,
  34 };
  35
  36 static const struct rhashtable_params fast_tx_rht_params = {
  37         .nelem_hint = 10,
  38         .automatic_shrinking = true,
  39         .key_len = ETH_ALEN,
  40         .key_offset = offsetof(struct ieee80211_mesh_fast_tx, addr_key),
  41         .head_offset = offsetof(struct ieee80211_mesh_fast_tx, rhash),
  42         .hashfn = mesh_table_hash,
  43 };
  44
  45 static void __mesh_fast_tx_entry_free(void *ptr, void *tblptr)
  46 {
  47         struct ieee80211_mesh_fast_tx *entry = ptr;
  48
  49         kfree_rcu(entry, fast_tx.rcu_head);
  50 }
  51
  52 static void mesh_fast_tx_deinit(struct ieee80211_sub_if_data *sdata)
  53 {
  54         struct mesh_tx_cache *cache;
  55
  56         cache = &sdata->u.mesh.tx_cache;
  57         rhashtable_free_and_destroy(&cache->rht,
  58                                     __mesh_fast_tx_entry_free, NULL);
  59 }
  60
  61 static void mesh_fast_tx_init(struct ieee80211_sub_if_data *sdata)
  62 {
  63         struct mesh_tx_cache *cache;
  64
  65         cache = &sdata->u.mesh.tx_cache;
  66         rhashtable_init(&cache->rht, &fast_tx_rht_params);
  67         INIT_HLIST_HEAD(&cache->walk_head);
  68         spin_lock_init(&cache->walk_lock);
  69 }
  70
  71 static inline bool mpath_expired(struct mesh_path *mpath)
  72 {
  73         return (mpath->flags & MESH_PATH_ACTIVE) &&
  74                time_after(jiffies, mpath->exp_time) &&
  75                !(mpath->flags & MESH_PATH_FIXED);
  76 }
  77
  78 static void mesh_path_rht_free(void *ptr, void *tblptr)
  79 {
  80         struct mesh_path *mpath = ptr;
  81         struct mesh_table *tbl = tblptr;
  82
  83         mesh_path_free_rcu(tbl, mpath);
  84 }
  85
  86 static void mesh_table_init(struct mesh_table *tbl)
  87 {
  88         INIT_HLIST_HEAD(&tbl->known_gates);
  89         INIT_HLIST_HEAD(&tbl->walk_head);
  90         atomic_set(&tbl->entries,  0);
  91         spin_lock_init(&tbl->gates_lock);
  92         spin_lock_init(&tbl->walk_lock);
  93
  94         /* rhashtable_init() may fail only in case of wrong
  95          * mesh_rht_params
  96          */
  97         WARN_ON(rhashtable_init(&tbl->rhead, &mesh_rht_params));
  98 }
  99
 100 static void mesh_table_free(struct mesh_table *tbl)
 101 {
 102         rhashtable_free_and_destroy(&tbl->rhead,
 103                                     mesh_path_rht_free, tbl);
 104 }
 105
 106 /**
 107  * mesh_path_assign_nexthop - update mesh path next hop
 108  *
 109  * @mpath: mesh path to update
 110  * @sta: next hop to assign
 111  *
 112  * Locking: mpath->state_lock must be held when calling this function
 113  */
 114 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 115 {
 116         struct sk_buff *skb;
 117         struct ieee80211_hdr *hdr;
 118         unsigned long flags;
 119
 120         rcu_assign_pointer(mpath->next_hop, sta);
 121
 122         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 123         skb_queue_walk(&mpath->frame_queue, skb) {
 124                 hdr = (struct ieee80211_hdr *) skb->data;
 125                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 126                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 127                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 128         }
 129
 130         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 131 }
 132
 133 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 134                              struct mesh_path *gate_mpath)
 135 {
 136         struct ieee80211_hdr *hdr;
 137         struct ieee80211s_hdr *mshdr;
 138         int mesh_hdrlen, hdrlen;
 139         char *next_hop;
 140
 141         hdr = (struct ieee80211_hdr *) skb->data;
 142         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 143         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 144
 145         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 146                 /* size of the fixed part of the mesh header */
 147                 mesh_hdrlen = 6;
 148
 149                 /* make room for the two extended addresses */
 150                 skb_push(skb, 2 * ETH_ALEN);
 151                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 152
 153                 hdr = (struct ieee80211_hdr *) skb->data;
 154
 155                 /* we preserve the previous mesh header and only add
 156                  * the new addresses */
 157                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 158                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 159                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 160                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 161         }
 162
 163         /* update next hop */
 164         hdr = (struct ieee80211_hdr *) skb->data;
 165         rcu_read_lock();
 166         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 167         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 168         rcu_read_unlock();
 169         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 170         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 171 }
 172
 173 /**
 174  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 175  *
 176  * This function is used to transfer or copy frames from an unresolved mpath to
 177  * a gate mpath.  The function also adds the Address Extension field and
 178  * updates the next hop.
 179  *
 180  * If a frame already has an Address Extension field, only the next hop and
 181  * destination addresses are updated.
 182  *
 183  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 184  *
 185  * @gate_mpath: An active mpath the frames will be sent to (i.e. the gate)
 186  * @from_mpath: The failed mpath
 187  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 188  * move them.
 189  */
 190 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 191                                     struct mesh_path *from_mpath,
 192                                     bool copy)
 193 {
 194         struct sk_buff *skb, *fskb, *tmp;
 195         struct sk_buff_head failq;
 196         unsigned long flags;
 197
 198         if (WARN_ON(gate_mpath == from_mpath))
 199                 return;
 200         if (WARN_ON(!gate_mpath->next_hop))
 201                 return;
 202
 203         __skb_queue_head_init(&failq);
 204
 205         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 206         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 207         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 208
 209         skb_queue_walk_safe(&failq, fskb, tmp) {
 210                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 211                                   MESH_FRAME_QUEUE_LEN) {
 212                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 213                         break;
 214                 }
 215
 216                 skb = skb_copy(fskb, GFP_ATOMIC);
 217                 if (WARN_ON(!skb))
 218                         break;
 219
 220                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 221                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 222
 223                 if (copy)
 224                         continue;
 225
 226                 __skb_unlink(fskb, &failq);
 227                 kfree_skb(fskb);
 228         }
 229
 230         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 231                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 232
 233         if (!copy)
 234                 return;
 235
 236         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 237         skb_queue_splice(&failq, &from_mpath->frame_queue);
 238         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 239 }
 240
 241
 242 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 243                                       struct ieee80211_sub_if_data *sdata)
 244 {
 245         struct mesh_path *mpath;
 246
 247         mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
 248
 249         if (mpath && mpath_expired(mpath)) {
 250                 spin_lock_bh(&mpath->state_lock);
 251                 mpath->flags &= ~MESH_PATH_ACTIVE;
 252                 spin_unlock_bh(&mpath->state_lock);
 253         }
 254         return mpath;
 255 }
 256
 257 /**
 258  * mesh_path_lookup - look up a path in the mesh path table
 259  * @sdata: local subif
 260  * @dst: hardware address (ETH_ALEN length) of destination
 261  *
 262  * Returns: pointer to the mesh path structure, or NULL if not found
 263  *
 264  * Locking: must be called within a read rcu section.
 265  */
 266 struct mesh_path *
 267 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 268 {
 269         return mpath_lookup(&sdata->u.mesh.mesh_paths, dst, sdata);
 270 }
 271
 272 struct mesh_path *
 273 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 274 {
 275         return mpath_lookup(&sdata->u.mesh.mpp_paths, dst, sdata);
 276 }
 277
 278 static struct mesh_path *
 279 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
 280 {
 281         int i = 0;
 282         struct mesh_path *mpath;
 283
 284         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 285                 if (i++ == idx)
 286                         break;
 287         }
 288
 289         if (!mpath)
 290                 return NULL;
 291
 292         if (mpath_expired(mpath)) {
 293                 spin_lock_bh(&mpath->state_lock);
 294                 mpath->flags &= ~MESH_PATH_ACTIVE;
 295                 spin_unlock_bh(&mpath->state_lock);
 296         }
 297         return mpath;
 298 }
 299
 300 /**
 301  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 302  * @idx: index
 303  * @sdata: local subif, or NULL for all entries
 304  *
 305  * Returns: pointer to the mesh path structure, or NULL if not found.
 306  *
 307  * Locking: must be called within a read rcu section.
 308  */
 309 struct mesh_path *
 310 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 311 {
 312         return __mesh_path_lookup_by_idx(&sdata->u.mesh.mesh_paths, idx);
 313 }
 314
 315 /**
 316  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 317  * @idx: index
 318  * @sdata: local subif, or NULL for all entries
 319  *
 320  * Returns: pointer to the proxy path structure, or NULL if not found.
 321  *
 322  * Locking: must be called within a read rcu section.
 323  */
 324 struct mesh_path *
 325 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 326 {
 327         return __mesh_path_lookup_by_idx(&sdata->u.mesh.mpp_paths, idx);
 328 }
 329
 330 /**
 331  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 332  * @mpath: gate path to add to table
 333  */
 334 int mesh_path_add_gate(struct mesh_path *mpath)
 335 {
 336         struct mesh_table *tbl;
 337         int err;
 338
 339         rcu_read_lock();
 340         tbl = &mpath->sdata->u.mesh.mesh_paths;
 341
 342         spin_lock_bh(&mpath->state_lock);
 343         if (mpath->is_gate) {
 344                 err = -EEXIST;
 345                 spin_unlock_bh(&mpath->state_lock);
 346                 goto err_rcu;
 347         }
 348         mpath->is_gate = true;
 349         mpath->sdata->u.mesh.num_gates++;
 350
 351         spin_lock(&tbl->gates_lock);
 352         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
 353         spin_unlock(&tbl->gates_lock);
 354
 355         spin_unlock_bh(&mpath->state_lock);
 356
 357         mpath_dbg(mpath->sdata,
 358                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 359                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 360         err = 0;
 361 err_rcu:
 362         rcu_read_unlock();
 363         return err;
 364 }
 365
 366 /**
 367  * mesh_gate_del - remove a mesh gate from the list of known gates
 368  * @tbl: table which holds our list of known gates
 369  * @mpath: gate mpath
 370  */
 371 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 372 {
 373         lockdep_assert_held(&mpath->state_lock);
 374         if (!mpath->is_gate)
 375                 return;
 376
 377         mpath->is_gate = false;
 378         spin_lock_bh(&tbl->gates_lock);
 379         hlist_del_rcu(&mpath->gate_list);
 380         mpath->sdata->u.mesh.num_gates--;
 381         spin_unlock_bh(&tbl->gates_lock);
 382
 383         mpath_dbg(mpath->sdata,
 384                   "Mesh path: Deleted gate: %pM. %d known gates\n",
 385                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 386 }
 387
 388 /**
 389  * mesh_gate_num - number of gates known to this interface
 390  * @sdata: subif data
 391  */
 392 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 393 {
 394         return sdata->u.mesh.num_gates;
 395 }
 396
 397 static
 398 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
 399                                 const u8 *dst, gfp_t gfp_flags)
 400 {
 401         struct mesh_path *new_mpath;
 402
 403         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
 404         if (!new_mpath)
 405                 return NULL;
 406
 407         memcpy(new_mpath->dst, dst, ETH_ALEN);
 408         eth_broadcast_addr(new_mpath->rann_snd_addr);
 409         new_mpath->is_root = false;
 410         new_mpath->sdata = sdata;
 411         new_mpath->flags = 0;
 412         skb_queue_head_init(&new_mpath->frame_queue);
 413         new_mpath->exp_time = jiffies;
 414         spin_lock_init(&new_mpath->state_lock);
 415         timer_setup(&new_mpath->timer, mesh_path_timer, 0);
 416
 417         return new_mpath;
 418 }
 419
 420 static void mesh_fast_tx_entry_free(struct mesh_tx_cache *cache,
 421                                     struct ieee80211_mesh_fast_tx *entry)
 422 {
 423         hlist_del_rcu(&entry->walk_list);
 424         rhashtable_remove_fast(&cache->rht, &entry->rhash, fast_tx_rht_params);
 425         kfree_rcu(entry, fast_tx.rcu_head);
 426 }
 427
 428 struct ieee80211_mesh_fast_tx *
 429 mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 430 {
 431         struct ieee80211_mesh_fast_tx *entry;
 432         struct mesh_tx_cache *cache;
 433
 434         cache = &sdata->u.mesh.tx_cache;
 435         entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
 436         if (!entry)
 437                 return NULL;
 438
 439         if (!(entry->mpath->flags & MESH_PATH_ACTIVE) ||
 440             mpath_expired(entry->mpath)) {
 441                 spin_lock_bh(&cache->walk_lock);
 442                 entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
 443                 if (entry)
 444                     mesh_fast_tx_entry_free(cache, entry);
 445                 spin_unlock_bh(&cache->walk_lock);
 446                 return NULL;
 447         }
 448
 449         mesh_path_refresh(sdata, entry->mpath, NULL);
 450         if (entry->mppath)
 451                 entry->mppath->exp_time = jiffies;
 452         entry->timestamp = jiffies;
 453
 454         return entry;
 455 }
 456
 457 void mesh_fast_tx_cache(struct ieee80211_sub_if_data *sdata,
 458                         struct sk_buff *skb, struct mesh_path *mpath)
 459 {
 460         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 461         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 462         struct ieee80211_mesh_fast_tx *entry, *prev;
 463         struct ieee80211_mesh_fast_tx build = {};
 464         struct ieee80211s_hdr *meshhdr;
 465         struct mesh_tx_cache *cache;
 466         struct ieee80211_key *key;
 467         struct mesh_path *mppath;
 468         struct sta_info *sta;
 469         u8 *qc;
 470
 471         if (sdata->noack_map ||
 472             !ieee80211_is_data_qos(hdr->frame_control))
 473                 return;
 474
 475         build.fast_tx.hdr_len = ieee80211_hdrlen(hdr->frame_control);
 476         meshhdr = (struct ieee80211s_hdr *)(skb->data + build.fast_tx.hdr_len);
 477         build.hdrlen = ieee80211_get_mesh_hdrlen(meshhdr);
 478
 479         cache = &sdata->u.mesh.tx_cache;
 480         if (atomic_read(&cache->rht.nelems) >= MESH_FAST_TX_CACHE_MAX_SIZE)
 481                 return;
 482
 483         sta = rcu_dereference(mpath->next_hop);
 484         if (!sta)
 485                 return;
 486
 487         if ((meshhdr->flags & MESH_FLAGS_AE) == MESH_FLAGS_AE_A5_A6) {
 488                 /* This is required to keep the mppath alive */
 489                 mppath = mpp_path_lookup(sdata, meshhdr->eaddr1);
 490                 if (!mppath)
 491                         return;
 492                 build.mppath = mppath;
 493         } else if (ieee80211_has_a4(hdr->frame_control)) {
 494                 mppath = mpath;
 495         } else {
 496                 return;
 497         }
 498
 499         /* rate limit, in case fast xmit can't be enabled */
 500         if (mppath->fast_tx_check == jiffies)
 501                 return;
 502
 503         mppath->fast_tx_check = jiffies;
 504
 505         /*
 506          * Same use of the sta lock as in ieee80211_check_fast_xmit, in order
 507          * to protect against concurrent sta key updates.
 508          */
 509         spin_lock_bh(&sta->lock);
 510         key = rcu_access_pointer(sta->ptk[sta->ptk_idx]);
 511         if (!key)
 512                 key = rcu_access_pointer(sdata->default_unicast_key);
 513         build.fast_tx.key = key;
 514
 515         if (key) {
 516                 bool gen_iv, iv_spc;
 517
 518                 gen_iv = key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV;
 519                 iv_spc = key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE;
 520
 521                 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) ||
 522                     (key->flags & KEY_FLAG_TAINTED))
 523                         goto unlock_sta;
 524
 525                 switch (key->conf.cipher) {
 526                 case WLAN_CIPHER_SUITE_CCMP:
 527                 case WLAN_CIPHER_SUITE_CCMP_256:
 528                         if (gen_iv)
 529                                 build.fast_tx.pn_offs = build.fast_tx.hdr_len;
 530                         if (gen_iv || iv_spc)
 531                                 build.fast_tx.hdr_len += IEEE80211_CCMP_HDR_LEN;
 532                         break;
 533                 case WLAN_CIPHER_SUITE_GCMP:
 534                 case WLAN_CIPHER_SUITE_GCMP_256:
 535                         if (gen_iv)
 536                                 build.fast_tx.pn_offs = build.fast_tx.hdr_len;
 537                         if (gen_iv || iv_spc)
 538                                 build.fast_tx.hdr_len += IEEE80211_GCMP_HDR_LEN;
 539                         break;
 540                 default:
 541                         goto unlock_sta;
 542                 }
 543         }
 544
 545         memcpy(build.addr_key, mppath->dst, ETH_ALEN);
 546         build.timestamp = jiffies;
 547         build.fast_tx.band = info->band;
 548         build.fast_tx.da_offs = offsetof(struct ieee80211_hdr, addr3);
 549         build.fast_tx.sa_offs = offsetof(struct ieee80211_hdr, addr4);
 550         build.mpath = mpath;
 551         memcpy(build.hdr, meshhdr, build.hdrlen);
 552         memcpy(build.hdr + build.hdrlen, rfc1042_header, sizeof(rfc1042_header));
 553         build.hdrlen += sizeof(rfc1042_header);
 554         memcpy(build.fast_tx.hdr, hdr, build.fast_tx.hdr_len);
 555
 556         hdr = (struct ieee80211_hdr *)build.fast_tx.hdr;
 557         if (build.fast_tx.key)
 558                 hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 559
 560         qc = ieee80211_get_qos_ctl(hdr);
 561         qc[1] |= IEEE80211_QOS_CTL_MESH_CONTROL_PRESENT >> 8;
 562
 563         entry = kmemdup(&build, sizeof(build), GFP_ATOMIC);
 564         if (!entry)
 565                 goto unlock_sta;
 566
 567         spin_lock(&cache->walk_lock);
 568         prev = rhashtable_lookup_get_insert_fast(&cache->rht,
 569                                                  &entry->rhash,
 570                                                  fast_tx_rht_params);
 571         if (unlikely(IS_ERR(prev))) {
 572                 kfree(entry);
 573                 goto unlock_cache;
 574         }
 575
 576         /*
 577          * replace any previous entry in the hash table, in case we're
 578          * replacing it with a different type (e.g. mpath -> mpp)
 579          */
 580         if (unlikely(prev)) {
 581                 rhashtable_replace_fast(&cache->rht, &prev->rhash,
 582                                         &entry->rhash, fast_tx_rht_params);
 583                 hlist_del_rcu(&prev->walk_list);
 584                 kfree_rcu(prev, fast_tx.rcu_head);
 585         }
 586
 587         hlist_add_head(&entry->walk_list, &cache->walk_head);
 588
 589 unlock_cache:
 590         spin_unlock(&cache->walk_lock);
 591 unlock_sta:
 592         spin_unlock_bh(&sta->lock);
 593 }
 594
 595 void mesh_fast_tx_gc(struct ieee80211_sub_if_data *sdata)
 596 {
 597         unsigned long timeout = msecs_to_jiffies(MESH_FAST_TX_CACHE_TIMEOUT);
 598         struct mesh_tx_cache *cache;
 599         struct ieee80211_mesh_fast_tx *entry;
 600         struct hlist_node *n;
 601
 602         cache = &sdata->u.mesh.tx_cache;
 603         if (atomic_read(&cache->rht.nelems) < MESH_FAST_TX_CACHE_THRESHOLD_SIZE)
 604                 return;
 605
 606         spin_lock_bh(&cache->walk_lock);
 607         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 608                 if (!time_is_after_jiffies(entry->timestamp + timeout))
 609                         mesh_fast_tx_entry_free(cache, entry);
 610         spin_unlock_bh(&cache->walk_lock);
 611 }
 612
 613 void mesh_fast_tx_flush_mpath(struct mesh_path *mpath)
 614 {
 615         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 616         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 617         struct ieee80211_mesh_fast_tx *entry;
 618         struct hlist_node *n;
 619
 620         cache = &sdata->u.mesh.tx_cache;
 621         spin_lock_bh(&cache->walk_lock);
 622         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 623                 if (entry->mpath == mpath)
 624                         mesh_fast_tx_entry_free(cache, entry);
 625         spin_unlock_bh(&cache->walk_lock);
 626 }
 627
 628 void mesh_fast_tx_flush_sta(struct ieee80211_sub_if_data *sdata,
 629                             struct sta_info *sta)
 630 {
 631         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 632         struct ieee80211_mesh_fast_tx *entry;
 633         struct hlist_node *n;
 634
 635         cache = &sdata->u.mesh.tx_cache;
 636         spin_lock_bh(&cache->walk_lock);
 637         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 638                 if (rcu_access_pointer(entry->mpath->next_hop) == sta)
 639                         mesh_fast_tx_entry_free(cache, entry);
 640         spin_unlock_bh(&cache->walk_lock);
 641 }
 642
 643 void mesh_fast_tx_flush_addr(struct ieee80211_sub_if_data *sdata,
 644                              const u8 *addr)
 645 {
 646         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 647         struct ieee80211_mesh_fast_tx *entry;
 648
 649         cache = &sdata->u.mesh.tx_cache;
 650         spin_lock_bh(&cache->walk_lock);
 651         entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
 652         if (entry)
 653                 mesh_fast_tx_entry_free(cache, entry);
 654         spin_unlock_bh(&cache->walk_lock);
 655 }
 656
 657 /**
 658  * mesh_path_add - allocate and add a new path to the mesh path table
 659  * @dst: destination address of the path (ETH_ALEN length)
 660  * @sdata: local subif
 661  *
 662  * Returns: 0 on success
 663  *
 664  * State: the initial state of the new path is set to 0
 665  */
 666 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 667                                 const u8 *dst)
 668 {
 669         struct mesh_table *tbl;
 670         struct mesh_path *mpath, *new_mpath;
 671
 672         if (ether_addr_equal(dst, sdata->vif.addr))
 673                 /* never add ourselves as neighbours */
 674                 return ERR_PTR(-ENOTSUPP);
 675
 676         if (is_multicast_ether_addr(dst))
 677                 return ERR_PTR(-ENOTSUPP);
 678
 679         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 680                 return ERR_PTR(-ENOSPC);
 681
 682         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 683         if (!new_mpath)
 684                 return ERR_PTR(-ENOMEM);
 685
 686         tbl = &sdata->u.mesh.mesh_paths;
 687         spin_lock_bh(&tbl->walk_lock);
 688         mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
 689                                                   &new_mpath->rhash,
 690                                                   mesh_rht_params);
 691         if (!mpath)
 692                 hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
 693         spin_unlock_bh(&tbl->walk_lock);
 694
 695         if (mpath) {
 696                 kfree(new_mpath);
 697
 698                 if (IS_ERR(mpath))
 699                         return mpath;
 700
 701                 new_mpath = mpath;
 702         }
 703
 704         sdata->u.mesh.mesh_paths_generation++;
 705         return new_mpath;
 706 }
 707
 708 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 709                  const u8 *dst, const u8 *mpp)
 710 {
 711         struct mesh_table *tbl;
 712         struct mesh_path *new_mpath;
 713         int ret;
 714
 715         if (ether_addr_equal(dst, sdata->vif.addr))
 716                 /* never add ourselves as neighbours */
 717                 return -ENOTSUPP;
 718
 719         if (is_multicast_ether_addr(dst))
 720                 return -ENOTSUPP;
 721
 722         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 723
 724         if (!new_mpath)
 725                 return -ENOMEM;
 726
 727         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 728         tbl = &sdata->u.mesh.mpp_paths;
 729
 730         spin_lock_bh(&tbl->walk_lock);
 731         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
 732                                             &new_mpath->rhash,
 733                                             mesh_rht_params);
 734         if (!ret)
 735                 hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
 736         spin_unlock_bh(&tbl->walk_lock);
 737
 738         if (ret)
 739                 kfree(new_mpath);
 740         else
 741                 mesh_fast_tx_flush_addr(sdata, dst);
 742
 743         sdata->u.mesh.mpp_paths_generation++;
 744         return ret;
 745 }
 746
 747
 748 /**
 749  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 750  *
 751  * @sta: broken peer link
 752  *
 753  * This function must be called from the rate control algorithm if enough
 754  * delivery errors suggest that a peer link is no longer usable.
 755  */
 756 void mesh_plink_broken(struct sta_info *sta)
 757 {
 758         struct ieee80211_sub_if_data *sdata = sta->sdata;
 759         struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
 760         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 761         struct mesh_path *mpath;
 762
 763         rcu_read_lock();
 764         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 765                 if (rcu_access_pointer(mpath->next_hop) == sta &&
 766                     mpath->flags & MESH_PATH_ACTIVE &&
 767                     !(mpath->flags & MESH_PATH_FIXED)) {
 768                         spin_lock_bh(&mpath->state_lock);
 769                         mpath->flags &= ~MESH_PATH_ACTIVE;
 770                         ++mpath->sn;
 771                         spin_unlock_bh(&mpath->state_lock);
 772                         mesh_path_error_tx(sdata,
 773                                 sdata->u.mesh.mshcfg.element_ttl,
 774                                 mpath->dst, mpath->sn,
 775                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 776                 }
 777         }
 778         rcu_read_unlock();
 779 }
 780
 781 static void mesh_path_free_rcu(struct mesh_table *tbl,
 782                                struct mesh_path *mpath)
 783 {
 784         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 785
 786         spin_lock_bh(&mpath->state_lock);
 787         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
 788         mesh_gate_del(tbl, mpath);
 789         spin_unlock_bh(&mpath->state_lock);
 790         timer_shutdown_sync(&mpath->timer);
 791         atomic_dec(&sdata->u.mesh.mpaths);
 792         atomic_dec(&tbl->entries);
 793         mesh_path_flush_pending(mpath);
 794         kfree_rcu(mpath, rcu);
 795 }
 796
 797 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
 798 {
 799         hlist_del_rcu(&mpath->walk_list);
 800         rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
 801         if (tbl == &mpath->sdata->u.mesh.mpp_paths)
 802                 mesh_fast_tx_flush_addr(mpath->sdata, mpath->dst);
 803         else
 804                 mesh_fast_tx_flush_mpath(mpath);
 805         mesh_path_free_rcu(tbl, mpath);
 806 }
 807
 808 /**
 809  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 810  *
 811  * @sta: mesh peer to match
 812  *
 813  * RCU notes: this function is called when a mesh plink transitions from
 814  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 815  * allows path creation. This will happen before the sta can be freed (because
 816  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 817  * protected against the plink disappearing.
 818  */
 819 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 820 {
 821         struct ieee80211_sub_if_data *sdata = sta->sdata;
 822         struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
 823         struct mesh_path *mpath;
 824         struct hlist_node *n;
 825
 826         spin_lock_bh(&tbl->walk_lock);
 827         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 828                 if (rcu_access_pointer(mpath->next_hop) == sta)
 829                         __mesh_path_del(tbl, mpath);
 830         }
 831         spin_unlock_bh(&tbl->walk_lock);
 832 }
 833
 834 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
 835                                const u8 *proxy)
 836 {
 837         struct mesh_table *tbl = &sdata->u.mesh.mpp_paths;
 838         struct mesh_path *mpath;
 839         struct hlist_node *n;
 840
 841         spin_lock_bh(&tbl->walk_lock);
 842         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 843                 if (ether_addr_equal(mpath->mpp, proxy))
 844                         __mesh_path_del(tbl, mpath);
 845         }
 846         spin_unlock_bh(&tbl->walk_lock);
 847 }
 848
 849 static void table_flush_by_iface(struct mesh_table *tbl)
 850 {
 851         struct mesh_path *mpath;
 852         struct hlist_node *n;
 853
 854         spin_lock_bh(&tbl->walk_lock);
 855         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 856                 __mesh_path_del(tbl, mpath);
 857         }
 858         spin_unlock_bh(&tbl->walk_lock);
 859 }
 860
 861 /**
 862  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 863  *
 864  * This function deletes both mesh paths as well as mesh portal paths.
 865  *
 866  * @sdata: interface data to match
 867  *
 868  */
 869 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 870 {
 871         table_flush_by_iface(&sdata->u.mesh.mesh_paths);
 872         table_flush_by_iface(&sdata->u.mesh.mpp_paths);
 873 }
 874
 875 /**
 876  * table_path_del - delete a path from the mesh or mpp table
 877  *
 878  * @tbl: mesh or mpp path table
 879  * @sdata: local subif
 880  * @addr: dst address (ETH_ALEN length)
 881  *
 882  * Returns: 0 if successful
 883  */
 884 static int table_path_del(struct mesh_table *tbl,
 885                           struct ieee80211_sub_if_data *sdata,
 886                           const u8 *addr)
 887 {
 888         struct mesh_path *mpath;
 889
 890         spin_lock_bh(&tbl->walk_lock);
 891         mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
 892         if (!mpath) {
 893                 spin_unlock_bh(&tbl->walk_lock);
 894                 return -ENXIO;
 895         }
 896
 897         __mesh_path_del(tbl, mpath);
 898         spin_unlock_bh(&tbl->walk_lock);
 899         return 0;
 900 }
 901
 902
 903 /**
 904  * mesh_path_del - delete a mesh path from the table
 905  *
 906  * @addr: dst address (ETH_ALEN length)
 907  * @sdata: local subif
 908  *
 909  * Returns: 0 if successful
 910  */
 911 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 912 {
 913         int err;
 914
 915         /* flush relevant mpp entries first */
 916         mpp_flush_by_proxy(sdata, addr);
 917
 918         err = table_path_del(&sdata->u.mesh.mesh_paths, sdata, addr);
 919         sdata->u.mesh.mesh_paths_generation++;
 920         return err;
 921 }
 922
 923 /**
 924  * mesh_path_tx_pending - sends pending frames in a mesh path queue
 925  *
 926  * @mpath: mesh path to activate
 927  *
 928  * Locking: the state_lock of the mpath structure must NOT be held when calling
 929  * this function.
 930  */
 931 void mesh_path_tx_pending(struct mesh_path *mpath)
 932 {
 933         if (mpath->flags & MESH_PATH_ACTIVE)
 934                 ieee80211_add_pending_skbs(mpath->sdata->local,
 935                                 &mpath->frame_queue);
 936 }
 937
 938 /**
 939  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 940  *
 941  * @mpath: mesh path whose queue will be emptied
 942  *
 943  * If there is only one gate, the frames are transferred from the failed mpath
 944  * queue to that gate's queue.  If there are more than one gates, the frames
 945  * are copied from each gate to the next.  After frames are copied, the
 946  * mpath queues are emptied onto the transmission queue.
 947  */
 948 int mesh_path_send_to_gates(struct mesh_path *mpath)
 949 {
 950         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 951         struct mesh_table *tbl;
 952         struct mesh_path *from_mpath = mpath;
 953         struct mesh_path *gate;
 954         bool copy = false;
 955
 956         tbl = &sdata->u.mesh.mesh_paths;
 957
 958         rcu_read_lock();
 959         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 960                 if (gate->flags & MESH_PATH_ACTIVE) {
 961                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
 962                         mesh_path_move_to_queue(gate, from_mpath, copy);
 963                         from_mpath = gate;
 964                         copy = true;
 965                 } else {
 966                         mpath_dbg(sdata,
 967                                   "Not forwarding to %pM (flags %#x)\n",
 968                                   gate->dst, gate->flags);
 969                 }
 970         }
 971
 972         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 973                 mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
 974                 mesh_path_tx_pending(gate);
 975         }
 976         rcu_read_unlock();
 977
 978         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 979 }
 980
 981 /**
 982  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 983  *
 984  * @skb: frame to discard
 985  * @sdata: network subif the frame was to be sent through
 986  *
 987  * Locking: the function must me called within a rcu_read_lock region
 988  */
 989 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 990                              struct sk_buff *skb)
 991 {
 992         ieee80211_free_txskb(&sdata->local->hw, skb);
 993         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 994 }
 995
 996 /**
 997  * mesh_path_flush_pending - free the pending queue of a mesh path
 998  *
 999  * @mpath: mesh path whose queue has to be freed
1000  *
1001  * Locking: the function must me called within a rcu_read_lock region
1002  */
1003 void mesh_path_flush_pending(struct mesh_path *mpath)
1004 {
1005         struct sk_buff *skb;
1006
1007         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
1008                 mesh_path_discard_frame(mpath->sdata, skb);
1009 }
1010
1011 /**
1012  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1013  *
1014  * @mpath: the mesh path to modify
1015  * @next_hop: the next hop to force
1016  *
1017  * Locking: this function must be called holding mpath->state_lock
1018  */
1019 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1020 {
1021         spin_lock_bh(&mpath->state_lock);
1022         mesh_path_assign_nexthop(mpath, next_hop);
1023         mpath->sn = 0xffff;
1024         mpath->metric = 0;
1025         mpath->hop_count = 0;
1026         mpath->exp_time = 0;
1027         mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
1028         mesh_path_activate(mpath);
1029         mesh_fast_tx_flush_mpath(mpath);
1030         spin_unlock_bh(&mpath->state_lock);
1031         ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
1032         /* init it at a low value - 0 start is tricky */
1033         ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
1034         mesh_path_tx_pending(mpath);
1035 }
1036
1037 void mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
1038 {
1039         mesh_table_init(&sdata->u.mesh.mesh_paths);
1040         mesh_table_init(&sdata->u.mesh.mpp_paths);
1041         mesh_fast_tx_init(sdata);
1042 }
1043
1044 static
1045 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
1046                           struct mesh_table *tbl)
1047 {
1048         struct mesh_path *mpath;
1049         struct hlist_node *n;
1050
1051         spin_lock_bh(&tbl->walk_lock);
1052         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
1053                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1054                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1055                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1056                         __mesh_path_del(tbl, mpath);
1057         }
1058         spin_unlock_bh(&tbl->walk_lock);
1059 }
1060
1061 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1062 {
1063         mesh_path_tbl_expire(sdata, &sdata->u.mesh.mesh_paths);
1064         mesh_path_tbl_expire(sdata, &sdata->u.mesh.mpp_paths);
1065 }
1066
1067 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
1068 {
1069         mesh_fast_tx_deinit(sdata);
1070         mesh_table_free(&sdata->u.mesh.mesh_paths);
1071         mesh_table_free(&sdata->u.mesh.mpp_paths);
1072 }