net/mac80211/mesh_pathtbl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008, 2009 open80211s Ltd.
   4  * Copyright (C) 2023 Intel Corporation
   5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6  */
   7
   8 #include <linux/etherdevice.h>
   9 #include <linux/list.h>
  10 #include <linux/random.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/string.h>
  14 #include <net/mac80211.h>
  15 #include "wme.h"
  16 #include "ieee80211_i.h"
  17 #include "mesh.h"
  18 #include <linux/rhashtable.h>
  19
  20 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
  21
  22 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
  23 {
  24         /* Use last four bytes of hw addr as hash index */
  25         return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
  26 }
  27
  28 static const struct rhashtable_params mesh_rht_params = {
  29         .nelem_hint = 2,
  30         .automatic_shrinking = true,
  31         .key_len = ETH_ALEN,
  32         .key_offset = offsetof(struct mesh_path, dst),
  33         .head_offset = offsetof(struct mesh_path, rhash),
  34         .hashfn = mesh_table_hash,
  35 };
  36
  37 static const struct rhashtable_params fast_tx_rht_params = {
  38         .nelem_hint = 10,
  39         .automatic_shrinking = true,
  40         .key_len = ETH_ALEN,
  41         .key_offset = offsetof(struct ieee80211_mesh_fast_tx, addr_key),
  42         .head_offset = offsetof(struct ieee80211_mesh_fast_tx, rhash),
  43         .hashfn = mesh_table_hash,
  44 };
  45
  46 static void __mesh_fast_tx_entry_free(void *ptr, void *tblptr)
  47 {
  48         struct ieee80211_mesh_fast_tx *entry = ptr;
  49
  50         kfree_rcu(entry, fast_tx.rcu_head);
  51 }
  52
  53 static void mesh_fast_tx_deinit(struct ieee80211_sub_if_data *sdata)
  54 {
  55         struct mesh_tx_cache *cache;
  56
  57         cache = &sdata->u.mesh.tx_cache;
  58         rhashtable_free_and_destroy(&cache->rht,
  59                                     __mesh_fast_tx_entry_free, NULL);
  60 }
  61
  62 static void mesh_fast_tx_init(struct ieee80211_sub_if_data *sdata)
  63 {
  64         struct mesh_tx_cache *cache;
  65
  66         cache = &sdata->u.mesh.tx_cache;
  67         rhashtable_init(&cache->rht, &fast_tx_rht_params);
  68         INIT_HLIST_HEAD(&cache->walk_head);
  69         spin_lock_init(&cache->walk_lock);
  70 }
  71
  72 static inline bool mpath_expired(struct mesh_path *mpath)
  73 {
  74         return (mpath->flags & MESH_PATH_ACTIVE) &&
  75                time_after(jiffies, mpath->exp_time) &&
  76                !(mpath->flags & MESH_PATH_FIXED);
  77 }
  78
  79 static void mesh_path_rht_free(void *ptr, void *tblptr)
  80 {
  81         struct mesh_path *mpath = ptr;
  82         struct mesh_table *tbl = tblptr;
  83
  84         mesh_path_free_rcu(tbl, mpath);
  85 }
  86
  87 static void mesh_table_init(struct mesh_table *tbl)
  88 {
  89         INIT_HLIST_HEAD(&tbl->known_gates);
  90         INIT_HLIST_HEAD(&tbl->walk_head);
  91         atomic_set(&tbl->entries,  0);
  92         spin_lock_init(&tbl->gates_lock);
  93         spin_lock_init(&tbl->walk_lock);
  94
  95         /* rhashtable_init() may fail only in case of wrong
  96          * mesh_rht_params
  97          */
  98         WARN_ON(rhashtable_init(&tbl->rhead, &mesh_rht_params));
  99 }
 100
 101 static void mesh_table_free(struct mesh_table *tbl)
 102 {
 103         rhashtable_free_and_destroy(&tbl->rhead,
 104                                     mesh_path_rht_free, tbl);
 105 }
 106
 107 /**
 108  * mesh_path_assign_nexthop - update mesh path next hop
 109  *
 110  * @mpath: mesh path to update
 111  * @sta: next hop to assign
 112  *
 113  * Locking: mpath->state_lock must be held when calling this function
 114  */
 115 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 116 {
 117         struct sk_buff *skb;
 118         struct ieee80211_hdr *hdr;
 119         unsigned long flags;
 120
 121         rcu_assign_pointer(mpath->next_hop, sta);
 122
 123         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 124         skb_queue_walk(&mpath->frame_queue, skb) {
 125                 hdr = (struct ieee80211_hdr *) skb->data;
 126                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 127                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 128                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 129         }
 130
 131         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 132 }
 133
 134 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
 135                              struct mesh_path *gate_mpath)
 136 {
 137         struct ieee80211_hdr *hdr;
 138         struct ieee80211s_hdr *mshdr;
 139         int mesh_hdrlen, hdrlen;
 140         char *next_hop;
 141
 142         hdr = (struct ieee80211_hdr *) skb->data;
 143         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 144         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 145
 146         if (!(mshdr->flags & MESH_FLAGS_AE)) {
 147                 /* size of the fixed part of the mesh header */
 148                 mesh_hdrlen = 6;
 149
 150                 /* make room for the two extended addresses */
 151                 skb_push(skb, 2 * ETH_ALEN);
 152                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 153
 154                 hdr = (struct ieee80211_hdr *) skb->data;
 155
 156                 /* we preserve the previous mesh header and only add
 157                  * the new addresses */
 158                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 159                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
 160                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
 161                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
 162         }
 163
 164         /* update next hop */
 165         hdr = (struct ieee80211_hdr *) skb->data;
 166         rcu_read_lock();
 167         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
 168         memcpy(hdr->addr1, next_hop, ETH_ALEN);
 169         rcu_read_unlock();
 170         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
 171         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 172 }
 173
 174 /**
 175  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 176  *
 177  * @gate_mpath: An active mpath the frames will be sent to (i.e. the gate)
 178  * @from_mpath: The failed mpath
 179  * @copy: When true, copy all the frames to the new mpath queue.  When false,
 180  * move them.
 181  *
 182  * This function is used to transfer or copy frames from an unresolved mpath to
 183  * a gate mpath.  The function also adds the Address Extension field and
 184  * updates the next hop.
 185  *
 186  * If a frame already has an Address Extension field, only the next hop and
 187  * destination addresses are updated.
 188  *
 189  * The gate mpath must be an active mpath with a valid mpath->next_hop.
 190  */
 191 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 192                                     struct mesh_path *from_mpath,
 193                                     bool copy)
 194 {
 195         struct sk_buff *skb, *fskb, *tmp;
 196         struct sk_buff_head failq;
 197         unsigned long flags;
 198
 199         if (WARN_ON(gate_mpath == from_mpath))
 200                 return;
 201         if (WARN_ON(!gate_mpath->next_hop))
 202                 return;
 203
 204         __skb_queue_head_init(&failq);
 205
 206         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 207         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
 208         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 209
 210         skb_queue_walk_safe(&failq, fskb, tmp) {
 211                 if (skb_queue_len(&gate_mpath->frame_queue) >=
 212                                   MESH_FRAME_QUEUE_LEN) {
 213                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
 214                         break;
 215                 }
 216
 217                 skb = skb_copy(fskb, GFP_ATOMIC);
 218                 if (WARN_ON(!skb))
 219                         break;
 220
 221                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
 222                 skb_queue_tail(&gate_mpath->frame_queue, skb);
 223
 224                 if (copy)
 225                         continue;
 226
 227                 __skb_unlink(fskb, &failq);
 228                 kfree_skb(fskb);
 229         }
 230
 231         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
 232                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 233
 234         if (!copy)
 235                 return;
 236
 237         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
 238         skb_queue_splice(&failq, &from_mpath->frame_queue);
 239         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 240 }
 241
 242
 243 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
 244                                       struct ieee80211_sub_if_data *sdata)
 245 {
 246         struct mesh_path *mpath;
 247
 248         mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
 249
 250         if (mpath && mpath_expired(mpath)) {
 251                 spin_lock_bh(&mpath->state_lock);
 252                 mpath->flags &= ~MESH_PATH_ACTIVE;
 253                 spin_unlock_bh(&mpath->state_lock);
 254         }
 255         return mpath;
 256 }
 257
 258 /**
 259  * mesh_path_lookup - look up a path in the mesh path table
 260  * @sdata: local subif
 261  * @dst: hardware address (ETH_ALEN length) of destination
 262  *
 263  * Returns: pointer to the mesh path structure, or NULL if not found
 264  *
 265  * Locking: must be called within a read rcu section.
 266  */
 267 struct mesh_path *
 268 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 269 {
 270         return mpath_lookup(&sdata->u.mesh.mesh_paths, dst, sdata);
 271 }
 272
 273 struct mesh_path *
 274 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 275 {
 276         return mpath_lookup(&sdata->u.mesh.mpp_paths, dst, sdata);
 277 }
 278
 279 static struct mesh_path *
 280 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
 281 {
 282         int i = 0;
 283         struct mesh_path *mpath;
 284
 285         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 286                 if (i++ == idx)
 287                         break;
 288         }
 289
 290         if (!mpath)
 291                 return NULL;
 292
 293         if (mpath_expired(mpath)) {
 294                 spin_lock_bh(&mpath->state_lock);
 295                 mpath->flags &= ~MESH_PATH_ACTIVE;
 296                 spin_unlock_bh(&mpath->state_lock);
 297         }
 298         return mpath;
 299 }
 300
 301 /**
 302  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 303  * @idx: index
 304  * @sdata: local subif, or NULL for all entries
 305  *
 306  * Returns: pointer to the mesh path structure, or NULL if not found.
 307  *
 308  * Locking: must be called within a read rcu section.
 309  */
 310 struct mesh_path *
 311 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 312 {
 313         return __mesh_path_lookup_by_idx(&sdata->u.mesh.mesh_paths, idx);
 314 }
 315
 316 /**
 317  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 318  * @idx: index
 319  * @sdata: local subif, or NULL for all entries
 320  *
 321  * Returns: pointer to the proxy path structure, or NULL if not found.
 322  *
 323  * Locking: must be called within a read rcu section.
 324  */
 325 struct mesh_path *
 326 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 327 {
 328         return __mesh_path_lookup_by_idx(&sdata->u.mesh.mpp_paths, idx);
 329 }
 330
 331 /**
 332  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 333  * @mpath: gate path to add to table
 334  *
 335  * Returns: 0 on success, -EEXIST
 336  */
 337 int mesh_path_add_gate(struct mesh_path *mpath)
 338 {
 339         struct mesh_table *tbl;
 340         int err;
 341
 342         rcu_read_lock();
 343         tbl = &mpath->sdata->u.mesh.mesh_paths;
 344
 345         spin_lock_bh(&mpath->state_lock);
 346         if (mpath->is_gate) {
 347                 err = -EEXIST;
 348                 spin_unlock_bh(&mpath->state_lock);
 349                 goto err_rcu;
 350         }
 351         mpath->is_gate = true;
 352         mpath->sdata->u.mesh.num_gates++;
 353
 354         spin_lock(&tbl->gates_lock);
 355         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
 356         spin_unlock(&tbl->gates_lock);
 357
 358         spin_unlock_bh(&mpath->state_lock);
 359
 360         mpath_dbg(mpath->sdata,
 361                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
 362                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 363         err = 0;
 364 err_rcu:
 365         rcu_read_unlock();
 366         return err;
 367 }
 368
 369 /**
 370  * mesh_gate_del - remove a mesh gate from the list of known gates
 371  * @tbl: table which holds our list of known gates
 372  * @mpath: gate mpath
 373  */
 374 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 375 {
 376         lockdep_assert_held(&mpath->state_lock);
 377         if (!mpath->is_gate)
 378                 return;
 379
 380         mpath->is_gate = false;
 381         spin_lock_bh(&tbl->gates_lock);
 382         hlist_del_rcu(&mpath->gate_list);
 383         mpath->sdata->u.mesh.num_gates--;
 384         spin_unlock_bh(&tbl->gates_lock);
 385
 386         mpath_dbg(mpath->sdata,
 387                   "Mesh path: Deleted gate: %pM. %d known gates\n",
 388                   mpath->dst, mpath->sdata->u.mesh.num_gates);
 389 }
 390
 391 /**
 392  * mesh_gate_num - number of gates known to this interface
 393  * @sdata: subif data
 394  *
 395  * Returns: The number of gates
 396  */
 397 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 398 {
 399         return sdata->u.mesh.num_gates;
 400 }
 401
 402 static
 403 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
 404                                 const u8 *dst, gfp_t gfp_flags)
 405 {
 406         struct mesh_path *new_mpath;
 407
 408         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
 409         if (!new_mpath)
 410                 return NULL;
 411
 412         memcpy(new_mpath->dst, dst, ETH_ALEN);
 413         eth_broadcast_addr(new_mpath->rann_snd_addr);
 414         new_mpath->is_root = false;
 415         new_mpath->sdata = sdata;
 416         new_mpath->flags = 0;
 417         skb_queue_head_init(&new_mpath->frame_queue);
 418         new_mpath->exp_time = jiffies;
 419         spin_lock_init(&new_mpath->state_lock);
 420         timer_setup(&new_mpath->timer, mesh_path_timer, 0);
 421
 422         return new_mpath;
 423 }
 424
 425 static void mesh_fast_tx_entry_free(struct mesh_tx_cache *cache,
 426                                     struct ieee80211_mesh_fast_tx *entry)
 427 {
 428         hlist_del_rcu(&entry->walk_list);
 429         rhashtable_remove_fast(&cache->rht, &entry->rhash, fast_tx_rht_params);
 430         kfree_rcu(entry, fast_tx.rcu_head);
 431 }
 432
 433 struct ieee80211_mesh_fast_tx *
 434 mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 435 {
 436         struct ieee80211_mesh_fast_tx *entry;
 437         struct mesh_tx_cache *cache;
 438
 439         cache = &sdata->u.mesh.tx_cache;
 440         entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
 441         if (!entry)
 442                 return NULL;
 443
 444         if (!(entry->mpath->flags & MESH_PATH_ACTIVE) ||
 445             mpath_expired(entry->mpath)) {
 446                 spin_lock_bh(&cache->walk_lock);
 447                 entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
 448                 if (entry)
 449                     mesh_fast_tx_entry_free(cache, entry);
 450                 spin_unlock_bh(&cache->walk_lock);
 451                 return NULL;
 452         }
 453
 454         mesh_path_refresh(sdata, entry->mpath, NULL);
 455         if (entry->mppath)
 456                 entry->mppath->exp_time = jiffies;
 457         entry->timestamp = jiffies;
 458
 459         return entry;
 460 }
 461
 462 void mesh_fast_tx_cache(struct ieee80211_sub_if_data *sdata,
 463                         struct sk_buff *skb, struct mesh_path *mpath)
 464 {
 465         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 466         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 467         struct ieee80211_mesh_fast_tx *entry, *prev;
 468         struct ieee80211_mesh_fast_tx build = {};
 469         struct ieee80211s_hdr *meshhdr;
 470         struct mesh_tx_cache *cache;
 471         struct ieee80211_key *key;
 472         struct mesh_path *mppath;
 473         struct sta_info *sta;
 474         u8 *qc;
 475
 476         if (sdata->noack_map ||
 477             !ieee80211_is_data_qos(hdr->frame_control))
 478                 return;
 479
 480         build.fast_tx.hdr_len = ieee80211_hdrlen(hdr->frame_control);
 481         meshhdr = (struct ieee80211s_hdr *)(skb->data + build.fast_tx.hdr_len);
 482         build.hdrlen = ieee80211_get_mesh_hdrlen(meshhdr);
 483
 484         cache = &sdata->u.mesh.tx_cache;
 485         if (atomic_read(&cache->rht.nelems) >= MESH_FAST_TX_CACHE_MAX_SIZE)
 486                 return;
 487
 488         sta = rcu_dereference(mpath->next_hop);
 489         if (!sta)
 490                 return;
 491
 492         if ((meshhdr->flags & MESH_FLAGS_AE) == MESH_FLAGS_AE_A5_A6) {
 493                 /* This is required to keep the mppath alive */
 494                 mppath = mpp_path_lookup(sdata, meshhdr->eaddr1);
 495                 if (!mppath)
 496                         return;
 497                 build.mppath = mppath;
 498         } else if (ieee80211_has_a4(hdr->frame_control)) {
 499                 mppath = mpath;
 500         } else {
 501                 return;
 502         }
 503
 504         /* rate limit, in case fast xmit can't be enabled */
 505         if (mppath->fast_tx_check == jiffies)
 506                 return;
 507
 508         mppath->fast_tx_check = jiffies;
 509
 510         /*
 511          * Same use of the sta lock as in ieee80211_check_fast_xmit, in order
 512          * to protect against concurrent sta key updates.
 513          */
 514         spin_lock_bh(&sta->lock);
 515         key = rcu_access_pointer(sta->ptk[sta->ptk_idx]);
 516         if (!key)
 517                 key = rcu_access_pointer(sdata->default_unicast_key);
 518         build.fast_tx.key = key;
 519
 520         if (key) {
 521                 bool gen_iv, iv_spc;
 522
 523                 gen_iv = key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV;
 524                 iv_spc = key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE;
 525
 526                 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) ||
 527                     (key->flags & KEY_FLAG_TAINTED))
 528                         goto unlock_sta;
 529
 530                 switch (key->conf.cipher) {
 531                 case WLAN_CIPHER_SUITE_CCMP:
 532                 case WLAN_CIPHER_SUITE_CCMP_256:
 533                         if (gen_iv)
 534                                 build.fast_tx.pn_offs = build.fast_tx.hdr_len;
 535                         if (gen_iv || iv_spc)
 536                                 build.fast_tx.hdr_len += IEEE80211_CCMP_HDR_LEN;
 537                         break;
 538                 case WLAN_CIPHER_SUITE_GCMP:
 539                 case WLAN_CIPHER_SUITE_GCMP_256:
 540                         if (gen_iv)
 541                                 build.fast_tx.pn_offs = build.fast_tx.hdr_len;
 542                         if (gen_iv || iv_spc)
 543                                 build.fast_tx.hdr_len += IEEE80211_GCMP_HDR_LEN;
 544                         break;
 545                 default:
 546                         goto unlock_sta;
 547                 }
 548         }
 549
 550         memcpy(build.addr_key, mppath->dst, ETH_ALEN);
 551         build.timestamp = jiffies;
 552         build.fast_tx.band = info->band;
 553         build.fast_tx.da_offs = offsetof(struct ieee80211_hdr, addr3);
 554         build.fast_tx.sa_offs = offsetof(struct ieee80211_hdr, addr4);
 555         build.mpath = mpath;
 556         memcpy(build.hdr, meshhdr, build.hdrlen);
 557         memcpy(build.hdr + build.hdrlen, rfc1042_header, sizeof(rfc1042_header));
 558         build.hdrlen += sizeof(rfc1042_header);
 559         memcpy(build.fast_tx.hdr, hdr, build.fast_tx.hdr_len);
 560
 561         hdr = (struct ieee80211_hdr *)build.fast_tx.hdr;
 562         if (build.fast_tx.key)
 563                 hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 564
 565         qc = ieee80211_get_qos_ctl(hdr);
 566         qc[1] |= IEEE80211_QOS_CTL_MESH_CONTROL_PRESENT >> 8;
 567
 568         entry = kmemdup(&build, sizeof(build), GFP_ATOMIC);
 569         if (!entry)
 570                 goto unlock_sta;
 571
 572         spin_lock(&cache->walk_lock);
 573         prev = rhashtable_lookup_get_insert_fast(&cache->rht,
 574                                                  &entry->rhash,
 575                                                  fast_tx_rht_params);
 576         if (unlikely(IS_ERR(prev))) {
 577                 kfree(entry);
 578                 goto unlock_cache;
 579         }
 580
 581         /*
 582          * replace any previous entry in the hash table, in case we're
 583          * replacing it with a different type (e.g. mpath -> mpp)
 584          */
 585         if (unlikely(prev)) {
 586                 rhashtable_replace_fast(&cache->rht, &prev->rhash,
 587                                         &entry->rhash, fast_tx_rht_params);
 588                 hlist_del_rcu(&prev->walk_list);
 589                 kfree_rcu(prev, fast_tx.rcu_head);
 590         }
 591
 592         hlist_add_head(&entry->walk_list, &cache->walk_head);
 593
 594 unlock_cache:
 595         spin_unlock(&cache->walk_lock);
 596 unlock_sta:
 597         spin_unlock_bh(&sta->lock);
 598 }
 599
 600 void mesh_fast_tx_gc(struct ieee80211_sub_if_data *sdata)
 601 {
 602         unsigned long timeout = msecs_to_jiffies(MESH_FAST_TX_CACHE_TIMEOUT);
 603         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 604         struct ieee80211_mesh_fast_tx *entry;
 605         struct hlist_node *n;
 606
 607         if (atomic_read(&cache->rht.nelems) < MESH_FAST_TX_CACHE_THRESHOLD_SIZE)
 608                 return;
 609
 610         spin_lock_bh(&cache->walk_lock);
 611         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 612                 if (!time_is_after_jiffies(entry->timestamp + timeout))
 613                         mesh_fast_tx_entry_free(cache, entry);
 614         spin_unlock_bh(&cache->walk_lock);
 615 }
 616
 617 void mesh_fast_tx_flush_mpath(struct mesh_path *mpath)
 618 {
 619         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 620         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 621         struct ieee80211_mesh_fast_tx *entry;
 622         struct hlist_node *n;
 623
 624         spin_lock_bh(&cache->walk_lock);
 625         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 626                 if (entry->mpath == mpath)
 627                         mesh_fast_tx_entry_free(cache, entry);
 628         spin_unlock_bh(&cache->walk_lock);
 629 }
 630
 631 void mesh_fast_tx_flush_sta(struct ieee80211_sub_if_data *sdata,
 632                             struct sta_info *sta)
 633 {
 634         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 635         struct ieee80211_mesh_fast_tx *entry;
 636         struct hlist_node *n;
 637
 638         spin_lock_bh(&cache->walk_lock);
 639         hlist_for_each_entry_safe(entry, n, &cache->walk_head, walk_list)
 640                 if (rcu_access_pointer(entry->mpath->next_hop) == sta)
 641                         mesh_fast_tx_entry_free(cache, entry);
 642         spin_unlock_bh(&cache->walk_lock);
 643 }
 644
 645 void mesh_fast_tx_flush_addr(struct ieee80211_sub_if_data *sdata,
 646                              const u8 *addr)
 647 {
 648         struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
 649         struct ieee80211_mesh_fast_tx *entry;
 650
 651         spin_lock_bh(&cache->walk_lock);
 652         entry = rhashtable_lookup_fast(&cache->rht, addr, fast_tx_rht_params);
 653         if (entry)
 654                 mesh_fast_tx_entry_free(cache, entry);
 655         spin_unlock_bh(&cache->walk_lock);
 656 }
 657
 658 /**
 659  * mesh_path_add - allocate and add a new path to the mesh path table
 660  * @dst: destination address of the path (ETH_ALEN length)
 661  * @sdata: local subif
 662  *
 663  * Returns: 0 on success
 664  *
 665  * State: the initial state of the new path is set to 0
 666  */
 667 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
 668                                 const u8 *dst)
 669 {
 670         struct mesh_table *tbl;
 671         struct mesh_path *mpath, *new_mpath;
 672
 673         if (ether_addr_equal(dst, sdata->vif.addr))
 674                 /* never add ourselves as neighbours */
 675                 return ERR_PTR(-EOPNOTSUPP);
 676
 677         if (is_multicast_ether_addr(dst))
 678                 return ERR_PTR(-EOPNOTSUPP);
 679
 680         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
 681                 return ERR_PTR(-ENOSPC);
 682
 683         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 684         if (!new_mpath)
 685                 return ERR_PTR(-ENOMEM);
 686
 687         tbl = &sdata->u.mesh.mesh_paths;
 688         spin_lock_bh(&tbl->walk_lock);
 689         mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
 690                                                   &new_mpath->rhash,
 691                                                   mesh_rht_params);
 692         if (!mpath)
 693                 hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
 694         spin_unlock_bh(&tbl->walk_lock);
 695
 696         if (mpath) {
 697                 kfree(new_mpath);
 698
 699                 if (IS_ERR(mpath))
 700                         return mpath;
 701
 702                 new_mpath = mpath;
 703         }
 704
 705         sdata->u.mesh.mesh_paths_generation++;
 706         return new_mpath;
 707 }
 708
 709 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
 710                  const u8 *dst, const u8 *mpp)
 711 {
 712         struct mesh_table *tbl;
 713         struct mesh_path *new_mpath;
 714         int ret;
 715
 716         if (ether_addr_equal(dst, sdata->vif.addr))
 717                 /* never add ourselves as neighbours */
 718                 return -EOPNOTSUPP;
 719
 720         if (is_multicast_ether_addr(dst))
 721                 return -EOPNOTSUPP;
 722
 723         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 724
 725         if (!new_mpath)
 726                 return -ENOMEM;
 727
 728         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
 729         tbl = &sdata->u.mesh.mpp_paths;
 730
 731         spin_lock_bh(&tbl->walk_lock);
 732         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
 733                                             &new_mpath->rhash,
 734                                             mesh_rht_params);
 735         if (!ret)
 736                 hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
 737         spin_unlock_bh(&tbl->walk_lock);
 738
 739         if (ret)
 740                 kfree(new_mpath);
 741         else
 742                 mesh_fast_tx_flush_addr(sdata, dst);
 743
 744         sdata->u.mesh.mpp_paths_generation++;
 745         return ret;
 746 }
 747
 748
 749 /**
 750  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 751  *
 752  * @sta: broken peer link
 753  *
 754  * This function must be called from the rate control algorithm if enough
 755  * delivery errors suggest that a peer link is no longer usable.
 756  */
 757 void mesh_plink_broken(struct sta_info *sta)
 758 {
 759         struct ieee80211_sub_if_data *sdata = sta->sdata;
 760         struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
 761         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 762         struct mesh_path *mpath;
 763
 764         rcu_read_lock();
 765         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
 766                 if (rcu_access_pointer(mpath->next_hop) == sta &&
 767                     mpath->flags & MESH_PATH_ACTIVE &&
 768                     !(mpath->flags & MESH_PATH_FIXED)) {
 769                         spin_lock_bh(&mpath->state_lock);
 770                         mpath->flags &= ~MESH_PATH_ACTIVE;
 771                         ++mpath->sn;
 772                         spin_unlock_bh(&mpath->state_lock);
 773                         mesh_path_error_tx(sdata,
 774                                 sdata->u.mesh.mshcfg.element_ttl,
 775                                 mpath->dst, mpath->sn,
 776                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
 777                 }
 778         }
 779         rcu_read_unlock();
 780 }
 781
 782 static void mesh_path_free_rcu(struct mesh_table *tbl,
 783                                struct mesh_path *mpath)
 784 {
 785         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 786
 787         spin_lock_bh(&mpath->state_lock);
 788         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
 789         mesh_gate_del(tbl, mpath);
 790         spin_unlock_bh(&mpath->state_lock);
 791         timer_shutdown_sync(&mpath->timer);
 792         atomic_dec(&sdata->u.mesh.mpaths);
 793         atomic_dec(&tbl->entries);
 794         mesh_path_flush_pending(mpath);
 795         kfree_rcu(mpath, rcu);
 796 }
 797
 798 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
 799 {
 800         hlist_del_rcu(&mpath->walk_list);
 801         rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
 802         if (tbl == &mpath->sdata->u.mesh.mpp_paths)
 803                 mesh_fast_tx_flush_addr(mpath->sdata, mpath->dst);
 804         else
 805                 mesh_fast_tx_flush_mpath(mpath);
 806         mesh_path_free_rcu(tbl, mpath);
 807 }
 808
 809 /**
 810  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 811  *
 812  * @sta: mesh peer to match
 813  *
 814  * RCU notes: this function is called when a mesh plink transitions from
 815  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 816  * allows path creation. This will happen before the sta can be freed (because
 817  * sta_info_destroy() calls this) so any reader in a rcu read block will be
 818  * protected against the plink disappearing.
 819  */
 820 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 821 {
 822         struct ieee80211_sub_if_data *sdata = sta->sdata;
 823         struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
 824         struct mesh_path *mpath;
 825         struct hlist_node *n;
 826
 827         spin_lock_bh(&tbl->walk_lock);
 828         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 829                 if (rcu_access_pointer(mpath->next_hop) == sta)
 830                         __mesh_path_del(tbl, mpath);
 831         }
 832         spin_unlock_bh(&tbl->walk_lock);
 833 }
 834
 835 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
 836                                const u8 *proxy)
 837 {
 838         struct mesh_table *tbl = &sdata->u.mesh.mpp_paths;
 839         struct mesh_path *mpath;
 840         struct hlist_node *n;
 841
 842         spin_lock_bh(&tbl->walk_lock);
 843         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 844                 if (ether_addr_equal(mpath->mpp, proxy))
 845                         __mesh_path_del(tbl, mpath);
 846         }
 847         spin_unlock_bh(&tbl->walk_lock);
 848 }
 849
 850 static void table_flush_by_iface(struct mesh_table *tbl)
 851 {
 852         struct mesh_path *mpath;
 853         struct hlist_node *n;
 854
 855         spin_lock_bh(&tbl->walk_lock);
 856         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
 857                 __mesh_path_del(tbl, mpath);
 858         }
 859         spin_unlock_bh(&tbl->walk_lock);
 860 }
 861
 862 /**
 863  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 864  *
 865  * @sdata: interface data to match
 866  *
 867  * This function deletes both mesh paths as well as mesh portal paths.
 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  * Returns: 0 on success, -EHOSTUNREACH
 949  */
 950 int mesh_path_send_to_gates(struct mesh_path *mpath)
 951 {
 952         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 953         struct mesh_table *tbl;
 954         struct mesh_path *from_mpath = mpath;
 955         struct mesh_path *gate;
 956         bool copy = false;
 957
 958         tbl = &sdata->u.mesh.mesh_paths;
 959
 960         rcu_read_lock();
 961         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 962                 if (gate->flags & MESH_PATH_ACTIVE) {
 963                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
 964                         mesh_path_move_to_queue(gate, from_mpath, copy);
 965                         from_mpath = gate;
 966                         copy = true;
 967                 } else {
 968                         mpath_dbg(sdata,
 969                                   "Not forwarding to %pM (flags %#x)\n",
 970                                   gate->dst, gate->flags);
 971                 }
 972         }
 973
 974         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
 975                 mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
 976                 mesh_path_tx_pending(gate);
 977         }
 978         rcu_read_unlock();
 979
 980         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 981 }
 982
 983 /**
 984  * mesh_path_discard_frame - discard a frame whose path could not be resolved
 985  *
 986  * @skb: frame to discard
 987  * @sdata: network subif the frame was to be sent through
 988  *
 989  * Locking: the function must me called within a rcu_read_lock region
 990  */
 991 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 992                              struct sk_buff *skb)
 993 {
 994         ieee80211_free_txskb(&sdata->local->hw, skb);
 995         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 996 }
 997
 998 /**
 999  * mesh_path_flush_pending - free the pending queue of a mesh path
1000  *
1001  * @mpath: mesh path whose queue has to be freed
1002  *
1003  * Locking: the function must me called within a rcu_read_lock region
1004  */
1005 void mesh_path_flush_pending(struct mesh_path *mpath)
1006 {
1007         struct sk_buff *skb;
1008
1009         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
1010                 mesh_path_discard_frame(mpath->sdata, skb);
1011 }
1012
1013 /**
1014  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
1015  *
1016  * @mpath: the mesh path to modify
1017  * @next_hop: the next hop to force
1018  *
1019  * Locking: this function must be called holding mpath->state_lock
1020  */
1021 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1022 {
1023         spin_lock_bh(&mpath->state_lock);
1024         mesh_path_assign_nexthop(mpath, next_hop);
1025         mpath->sn = 0xffff;
1026         mpath->metric = 0;
1027         mpath->hop_count = 0;
1028         mpath->exp_time = 0;
1029         mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
1030         mesh_path_activate(mpath);
1031         mesh_fast_tx_flush_mpath(mpath);
1032         spin_unlock_bh(&mpath->state_lock);
1033         ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
1034         /* init it at a low value - 0 start is tricky */
1035         ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
1036         mesh_path_tx_pending(mpath);
1037 }
1038
1039 void mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
1040 {
1041         mesh_table_init(&sdata->u.mesh.mesh_paths);
1042         mesh_table_init(&sdata->u.mesh.mpp_paths);
1043         mesh_fast_tx_init(sdata);
1044 }
1045
1046 static
1047 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
1048                           struct mesh_table *tbl)
1049 {
1050         struct mesh_path *mpath;
1051         struct hlist_node *n;
1052
1053         spin_lock_bh(&tbl->walk_lock);
1054         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
1055                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1056                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1057                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1058                         __mesh_path_del(tbl, mpath);
1059         }
1060         spin_unlock_bh(&tbl->walk_lock);
1061 }
1062
1063 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1064 {
1065         mesh_path_tbl_expire(sdata, &sdata->u.mesh.mesh_paths);
1066         mesh_path_tbl_expire(sdata, &sdata->u.mesh.mpp_paths);
1067 }
1068
1069 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
1070 {
1071         mesh_fast_tx_deinit(sdata);
1072         mesh_table_free(&sdata->u.mesh.mesh_paths);
1073         mesh_table_free(&sdata->u.mesh.mpp_paths);
1074 }