net/mac80211/mesh.c

   1 /*
   2  * Copyright (c) 2008 open80211s Ltd.
   3  * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
   4  *             Javier Cardona <javier@cozybit.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <asm/unaligned.h>
  12 #include "ieee80211_i.h"
  13 #include "mesh.h"
  14
  15 #define PP_OFFSET       1               /* Path Selection Protocol */
  16 #define PM_OFFSET       5               /* Path Selection Metric   */
  17 #define CC_OFFSET       9               /* Congestion Control Mode */
  18 #define CAPAB_OFFSET 17
  19 #define ACCEPT_PLINKS 0x80
  20
  21 int mesh_allocated;
  22 static struct kmem_cache *rm_cache;
  23
  24 void ieee80211s_init(void)
  25 {
  26         mesh_pathtbl_init();
  27         mesh_allocated = 1;
  28         rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
  29                                      0, 0, NULL);
  30 }
  31
  32 void ieee80211s_stop(void)
  33 {
  34         mesh_pathtbl_unregister();
  35         kmem_cache_destroy(rm_cache);
  36 }
  37
  38 /**
  39  * mesh_matches_local - check if the config of a mesh point matches ours
  40  *
  41  * @ie: information elements of a management frame from the mesh peer
  42  * @dev: local mesh interface
  43  *
  44  * This function checks if the mesh configuration of a mesh point matches the
  45  * local mesh configuration, i.e. if both nodes belong to the same mesh network.
  46  */
  47 bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev)
  48 {
  49         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  50         struct ieee80211_if_sta *sta = &sdata->u.sta;
  51
  52         /*
  53          * As support for each feature is added, check for matching
  54          * - On mesh config capabilities
  55          *   - Power Save Support En
  56          *   - Sync support enabled
  57          *   - Sync support active
  58          *   - Sync support required from peer
  59          *   - MDA enabled
  60          * - Power management control on fc
  61          */
  62         if (sta->mesh_id_len == ie->mesh_id_len &&
  63                 memcmp(sta->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&
  64                 memcmp(sta->mesh_pp_id, ie->mesh_config + PP_OFFSET, 4) == 0 &&
  65                 memcmp(sta->mesh_pm_id, ie->mesh_config + PM_OFFSET, 4) == 0 &&
  66                 memcmp(sta->mesh_cc_id, ie->mesh_config + CC_OFFSET, 4) == 0)
  67                 return true;
  68
  69         return false;
  70 }
  71
  72 /**
  73  * mesh_peer_accepts_plinks - check if an mp is willing to establish peer links
  74  *
  75  * @ie: information elements of a management frame from the mesh peer
  76  * @dev: local mesh interface
  77  */
  78 bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,
  79                               struct net_device *dev)
  80 {
  81         return (*(ie->mesh_config + CAPAB_OFFSET) & ACCEPT_PLINKS) != 0;
  82 }
  83
  84 /**
  85  * mesh_accept_plinks_update: update accepting_plink in local mesh beacons
  86  *
  87  * @sdata: mesh interface in which mesh beacons are going to be updated
  88  */
  89 void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)
  90 {
  91         bool free_plinks;
  92
  93         /* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
  94          * the mesh interface might be able to establish plinks with peers that
  95          * are already on the table but are not on PLINK_ESTAB state. However,
  96          * in general the mesh interface is not accepting peer link requests
  97          * from new peers, and that must be reflected in the beacon
  98          */
  99         free_plinks = mesh_plink_availables(sdata);
 100
 101         if (free_plinks != sdata->u.sta.accepting_plinks)
 102                 ieee80211_sta_timer((unsigned long) sdata);
 103 }
 104
 105 void mesh_ids_set_default(struct ieee80211_if_sta *sta)
 106 {
 107         u8 def_id[4] = {0x00, 0x0F, 0xAC, 0xff};
 108
 109         memcpy(sta->mesh_pp_id, def_id, 4);
 110         memcpy(sta->mesh_pm_id, def_id, 4);
 111         memcpy(sta->mesh_cc_id, def_id, 4);
 112 }
 113
 114 int mesh_rmc_init(struct net_device *dev)
 115 {
 116         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 117         int i;
 118
 119         sdata->u.sta.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);
 120         if (!sdata->u.sta.rmc)
 121                 return -ENOMEM;
 122         sdata->u.sta.rmc->idx_mask = RMC_BUCKETS - 1;
 123         for (i = 0; i < RMC_BUCKETS; i++)
 124                 INIT_LIST_HEAD(&sdata->u.sta.rmc->bucket[i].list);
 125         return 0;
 126 }
 127
 128 void mesh_rmc_free(struct net_device *dev)
 129 {
 130         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 131         struct mesh_rmc *rmc = sdata->u.sta.rmc;
 132         struct rmc_entry *p, *n;
 133         int i;
 134
 135         if (!sdata->u.sta.rmc)
 136                 return;
 137
 138         for (i = 0; i < RMC_BUCKETS; i++)
 139                 list_for_each_entry_safe(p, n, &rmc->bucket[i].list, list) {
 140                         list_del(&p->list);
 141                         kmem_cache_free(rm_cache, p);
 142                 }
 143
 144         kfree(rmc);
 145         sdata->u.sta.rmc = NULL;
 146 }
 147
 148 /**
 149  * mesh_rmc_check - Check frame in recent multicast cache and add if absent.
 150  *
 151  * @sa:         source address
 152  * @mesh_hdr:   mesh_header
 153  *
 154  * Returns: 0 if the frame is not in the cache, nonzero otherwise.
 155  *
 156  * Checks using the source address and the mesh sequence number if we have
 157  * received this frame lately. If the frame is not in the cache, it is added to
 158  * it.
 159  */
 160 int mesh_rmc_check(u8 *sa, struct ieee80211s_hdr *mesh_hdr,
 161                    struct net_device *dev)
 162 {
 163         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 164         struct mesh_rmc *rmc = sdata->u.sta.rmc;
 165         u32 seqnum = 0;
 166         int entries = 0;
 167         u8 idx;
 168         struct rmc_entry *p, *n;
 169
 170         /* Don't care about endianness since only match matters */
 171         memcpy(&seqnum, &mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));
 172         idx = le32_to_cpu(mesh_hdr->seqnum) & rmc->idx_mask;
 173         list_for_each_entry_safe(p, n, &rmc->bucket[idx].list, list) {
 174                 ++entries;
 175                 if (time_after(jiffies, p->exp_time) ||
 176                                 (entries == RMC_QUEUE_MAX_LEN)) {
 177                         list_del(&p->list);
 178                         kmem_cache_free(rm_cache, p);
 179                         --entries;
 180                 } else if ((seqnum == p->seqnum)
 181                                 && (memcmp(sa, p->sa, ETH_ALEN) == 0))
 182                         return -1;
 183         }
 184
 185         p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);
 186         if (!p) {
 187                 printk(KERN_DEBUG "o11s: could not allocate RMC entry\n");
 188                 return 0;
 189         }
 190         p->seqnum = seqnum;
 191         p->exp_time = jiffies + RMC_TIMEOUT;
 192         memcpy(p->sa, sa, ETH_ALEN);
 193         list_add(&p->list, &rmc->bucket[idx].list);
 194         return 0;
 195 }
 196
 197 void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev)
 198 {
 199         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 200         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 201         struct ieee80211_supported_band *sband;
 202         u8 *pos;
 203         int len, i, rate;
 204
 205         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 206         len = sband->n_bitrates;
 207         if (len > 8)
 208                 len = 8;
 209         pos = skb_put(skb, len + 2);
 210         *pos++ = WLAN_EID_SUPP_RATES;
 211         *pos++ = len;
 212         for (i = 0; i < len; i++) {
 213                 rate = sband->bitrates[i].bitrate;
 214                 *pos++ = (u8) (rate / 5);
 215         }
 216
 217         if (sband->n_bitrates > len) {
 218                 pos = skb_put(skb, sband->n_bitrates - len + 2);
 219                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 220                 *pos++ = sband->n_bitrates - len;
 221                 for (i = len; i < sband->n_bitrates; i++) {
 222                         rate = sband->bitrates[i].bitrate;
 223                         *pos++ = (u8) (rate / 5);
 224                 }
 225         }
 226
 227         pos = skb_put(skb, 2 + sdata->u.sta.mesh_id_len);
 228         *pos++ = WLAN_EID_MESH_ID;
 229         *pos++ = sdata->u.sta.mesh_id_len;
 230         if (sdata->u.sta.mesh_id_len)
 231                 memcpy(pos, sdata->u.sta.mesh_id, sdata->u.sta.mesh_id_len);
 232
 233         pos = skb_put(skb, 21);
 234         *pos++ = WLAN_EID_MESH_CONFIG;
 235         *pos++ = MESH_CFG_LEN;
 236         /* Version */
 237         *pos++ = 1;
 238
 239         /* Active path selection protocol ID */
 240         memcpy(pos, sdata->u.sta.mesh_pp_id, 4);
 241         pos += 4;
 242
 243         /* Active path selection metric ID   */
 244         memcpy(pos, sdata->u.sta.mesh_pm_id, 4);
 245         pos += 4;
 246
 247         /* Congestion control mode identifier */
 248         memcpy(pos, sdata->u.sta.mesh_cc_id, 4);
 249         pos += 4;
 250
 251         /* Channel precedence:
 252          * Not running simple channel unification protocol
 253          */
 254         memset(pos, 0x00, 4);
 255         pos += 4;
 256
 257         /* Mesh capability */
 258         sdata->u.sta.accepting_plinks = mesh_plink_availables(sdata);
 259         *pos++ = sdata->u.sta.accepting_plinks ? ACCEPT_PLINKS : 0x00;
 260         *pos++ = 0x00;
 261
 262         return;
 263 }
 264
 265 u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl)
 266 {
 267         /* Use last four bytes of hw addr and interface index as hash index */
 268         return jhash_2words(*(u32 *)(addr+2), dev->ifindex, tbl->hash_rnd)
 269                 & tbl->hash_mask;
 270 }
 271
 272 u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len)
 273 {
 274         if (!mesh_id_len)
 275                 return 1;
 276         else if (mesh_id_len == 1)
 277                 return (u8) mesh_id[0];
 278         else
 279                 return (u8) (mesh_id[0] + 2 * mesh_id[1]);
 280 }
 281
 282 struct mesh_table *mesh_table_alloc(int size_order)
 283 {
 284         int i;
 285         struct mesh_table *newtbl;
 286
 287         newtbl = kmalloc(sizeof(struct mesh_table), GFP_KERNEL);
 288         if (!newtbl)
 289                 return NULL;
 290
 291         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
 292                         (1 << size_order), GFP_KERNEL);
 293
 294         if (!newtbl->hash_buckets) {
 295                 kfree(newtbl);
 296                 return NULL;
 297         }
 298
 299         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
 300                         (1 << size_order), GFP_KERNEL);
 301         if (!newtbl->hashwlock) {
 302                 kfree(newtbl->hash_buckets);
 303                 kfree(newtbl);
 304                 return NULL;
 305         }
 306
 307         newtbl->size_order = size_order;
 308         newtbl->hash_mask = (1 << size_order) - 1;
 309         atomic_set(&newtbl->entries,  0);
 310         get_random_bytes(&newtbl->hash_rnd,
 311                         sizeof(newtbl->hash_rnd));
 312         for (i = 0; i <= newtbl->hash_mask; i++)
 313                 spin_lock_init(&newtbl->hashwlock[i]);
 314
 315         return newtbl;
 316 }
 317
 318 static void __mesh_table_free(struct mesh_table *tbl)
 319 {
 320         kfree(tbl->hash_buckets);
 321         kfree(tbl->hashwlock);
 322         kfree(tbl);
 323 }
 324
 325 void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
 326 {
 327         struct hlist_head *mesh_hash;
 328         struct hlist_node *p, *q;
 329         int i;
 330
 331         mesh_hash = tbl->hash_buckets;
 332         for (i = 0; i <= tbl->hash_mask; i++) {
 333                 spin_lock(&tbl->hashwlock[i]);
 334                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
 335                         tbl->free_node(p, free_leafs);
 336                         atomic_dec(&tbl->entries);
 337                 }
 338                 spin_unlock(&tbl->hashwlock[i]);
 339         }
 340         __mesh_table_free(tbl);
 341 }
 342
 343 static void ieee80211_mesh_path_timer(unsigned long data)
 344 {
 345         struct ieee80211_sub_if_data *sdata =
 346                 (struct ieee80211_sub_if_data *) data;
 347         struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 348         struct ieee80211_local *local = wdev_priv(&sdata->wdev);
 349
 350         queue_work(local->hw.workqueue, &ifsta->work);
 351 }
 352
 353 struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
 354 {
 355         struct mesh_table *newtbl;
 356         struct hlist_head *oldhash;
 357         struct hlist_node *p, *q;
 358         int i;
 359
 360         if (atomic_read(&tbl->entries)
 361                         < tbl->mean_chain_len * (tbl->hash_mask + 1))
 362                 goto endgrow;
 363
 364         newtbl = mesh_table_alloc(tbl->size_order + 1);
 365         if (!newtbl)
 366                 goto endgrow;
 367
 368         newtbl->free_node = tbl->free_node;
 369         newtbl->mean_chain_len = tbl->mean_chain_len;
 370         newtbl->copy_node = tbl->copy_node;
 371         atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
 372
 373         oldhash = tbl->hash_buckets;
 374         for (i = 0; i <= tbl->hash_mask; i++)
 375                 hlist_for_each(p, &oldhash[i])
 376                         if (tbl->copy_node(p, newtbl) < 0)
 377                                 goto errcopy;
 378
 379         return newtbl;
 380
 381 errcopy:
 382         for (i = 0; i <= newtbl->hash_mask; i++) {
 383                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
 384                         tbl->free_node(p, 0);
 385         }
 386         __mesh_table_free(newtbl);
 387 endgrow:
 388         return NULL;
 389 }
 390
 391 /**
 392  * ieee80211_new_mesh_header - create a new mesh header
 393  * @meshhdr:    uninitialized mesh header
 394  * @sdata:      mesh interface to be used
 395  *
 396  * Return the header length.
 397  */
 398 int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
 399                 struct ieee80211_sub_if_data *sdata)
 400 {
 401         meshhdr->flags = 0;
 402         meshhdr->ttl = sdata->u.sta.mshcfg.dot11MeshTTL;
 403         put_unaligned(cpu_to_le32(sdata->u.sta.mesh_seqnum), &meshhdr->seqnum);
 404         sdata->u.sta.mesh_seqnum++;
 405
 406         return 6;
 407 }
 408
 409 void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
 410 {
 411         struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 412
 413         ifsta->mshcfg.dot11MeshRetryTimeout = MESH_RET_T;
 414         ifsta->mshcfg.dot11MeshConfirmTimeout = MESH_CONF_T;
 415         ifsta->mshcfg.dot11MeshHoldingTimeout = MESH_HOLD_T;
 416         ifsta->mshcfg.dot11MeshMaxRetries = MESH_MAX_RETR;
 417         ifsta->mshcfg.dot11MeshTTL = MESH_TTL;
 418         ifsta->mshcfg.auto_open_plinks = true;
 419         ifsta->mshcfg.dot11MeshMaxPeerLinks =
 420                 MESH_MAX_ESTAB_PLINKS;
 421         ifsta->mshcfg.dot11MeshHWMPactivePathTimeout =
 422                 MESH_PATH_TIMEOUT;
 423         ifsta->mshcfg.dot11MeshHWMPpreqMinInterval =
 424                 MESH_PREQ_MIN_INT;
 425         ifsta->mshcfg.dot11MeshHWMPnetDiameterTraversalTime =
 426                 MESH_DIAM_TRAVERSAL_TIME;
 427         ifsta->mshcfg.dot11MeshHWMPmaxPREQretries =
 428                 MESH_MAX_PREQ_RETRIES;
 429         ifsta->mshcfg.path_refresh_time =
 430                 MESH_PATH_REFRESH_TIME;
 431         ifsta->mshcfg.min_discovery_timeout =
 432                 MESH_MIN_DISCOVERY_TIMEOUT;
 433         ifsta->accepting_plinks = true;
 434         ifsta->preq_id = 0;
 435         ifsta->dsn = 0;
 436         atomic_set(&ifsta->mpaths, 0);
 437         mesh_rmc_init(sdata->dev);
 438         ifsta->last_preq = jiffies;
 439         /* Allocate all mesh structures when creating the first mesh interface. */
 440         if (!mesh_allocated)
 441                 ieee80211s_init();
 442         mesh_ids_set_default(ifsta);
 443         setup_timer(&ifsta->mesh_path_timer,
 444                     ieee80211_mesh_path_timer,
 445                     (unsigned long) sdata);
 446         INIT_LIST_HEAD(&ifsta->preq_queue.list);
 447         spin_lock_init(&ifsta->mesh_preq_queue_lock);
 448 }