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