net/mac80211/mesh.h

   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 #ifndef IEEE80211S_H
  12 #define IEEE80211S_H
  13
  14 #include <linux/types.h>
  15 #include <linux/jhash.h>
  16 #include <asm/unaligned.h>
  17 #include "ieee80211_i.h"
  18
  19
  20 /* Data structures */
  21
  22 /**
  23  * enum mesh_path_flags - mac80211 mesh path flags
  24  *
  25  *
  26  *
  27  * @MESH_PATH_ACTIVE: the mesh path is can be used for forwarding
  28  * @MESH_PATH_RESOLVED: the discovery process is running for this mesh path
  29  * @MESH_PATH_DSN_VALID: the mesh path contains a valid destination sequence
  30  *      number
  31  * @MESH_PATH_FIXED: the mesh path has been manually set and should not be
  32  *      modified
  33  * @MESH_PATH_RESOLVED: the mesh path can has been resolved
  34  *
  35  * MESH_PATH_RESOLVED and MESH_PATH_DELETE are used by the mesh path timer to
  36  * decide when to stop or cancel the mesh path discovery.
  37  */
  38 enum mesh_path_flags {
  39         MESH_PATH_ACTIVE =      BIT(0),
  40         MESH_PATH_RESOLVING =   BIT(1),
  41         MESH_PATH_DSN_VALID =   BIT(2),
  42         MESH_PATH_FIXED =       BIT(3),
  43         MESH_PATH_RESOLVED =    BIT(4),
  44 };
  45
  46 /**
  47  * struct mesh_path - mac80211 mesh path structure
  48  *
  49  * @dst: mesh path destination mac address
  50  * @sdata: mesh subif
  51  * @next_hop: mesh neighbor to which frames for this destination will be
  52  *      forwarded
  53  * @timer: mesh path discovery timer
  54  * @frame_queue: pending queue for frames sent to this destination while the
  55  *      path is unresolved
  56  * @dsn: destination sequence number of the destination
  57  * @metric: current metric to this destination
  58  * @hop_count: hops to destination
  59  * @exp_time: in jiffies, when the path will expire or when it expired
  60  * @discovery_timeout: timeout (lapse in jiffies) used for the last discovery
  61  *      retry
  62  * @discovery_retries: number of discovery retries
  63  * @flags: mesh path flags, as specified on &enum mesh_path_flags
  64  * @state_lock: mesh pat state lock
  65  *
  66  *
  67  * The combination of dst and sdata is unique in the mesh path table. Since the
  68  * next_hop STA is only protected by RCU as well, deleting the STA must also
  69  * remove/substitute the mesh_path structure and wait until that is no longer
  70  * reachable before destroying the STA completely.
  71  */
  72 struct mesh_path {
  73         u8 dst[ETH_ALEN];
  74         struct ieee80211_sub_if_data *sdata;
  75         struct sta_info *next_hop;
  76         struct timer_list timer;
  77         struct sk_buff_head frame_queue;
  78         struct rcu_head rcu;
  79         u32 dsn;
  80         u32 metric;
  81         u8 hop_count;
  82         unsigned long exp_time;
  83         u32 discovery_timeout;
  84         u8 discovery_retries;
  85         enum mesh_path_flags flags;
  86         spinlock_t state_lock;
  87 };
  88
  89 /**
  90  * struct mesh_table
  91  *
  92  * @hash_buckets: array of hash buckets of the table
  93  * @hashwlock: array of locks to protect write operations, one per bucket
  94  * @hash_mask: 2^size_order - 1, used to compute hash idx
  95  * @hash_rnd: random value used for hash computations
  96  * @entries: number of entries in the table
  97  * @free_node: function to free nodes of the table
  98  * @copy_node: fuction to copy nodes of the table
  99  * @size_order: determines size of the table, there will be 2^size_order hash
 100  *      buckets
 101  * @mean_chain_len: maximum average length for the hash buckets' list, if it is
 102  *      reached, the table will grow
 103  */
 104 struct mesh_table {
 105         /* Number of buckets will be 2^N */
 106         struct hlist_head *hash_buckets;
 107         spinlock_t *hashwlock;          /* One per bucket, for add/del */
 108         unsigned int hash_mask;         /* (2^size_order) - 1 */
 109         __u32 hash_rnd;                 /* Used for hash generation */
 110         atomic_t entries;               /* Up to MAX_MESH_NEIGHBOURS */
 111         void (*free_node) (struct hlist_node *p, bool free_leafs);
 112         int (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);
 113         int size_order;
 114         int mean_chain_len;
 115 };
 116
 117 /* Recent multicast cache */
 118 /* RMC_BUCKETS must be a power of 2, maximum 256 */
 119 #define RMC_BUCKETS             256
 120 #define RMC_QUEUE_MAX_LEN       4
 121 #define RMC_TIMEOUT             (3 * HZ)
 122
 123 /**
 124  * struct rmc_entry - entry in the Recent Multicast Cache
 125  *
 126  * @seqnum: mesh sequence number of the frame
 127  * @exp_time: expiration time of the entry, in jiffies
 128  * @sa: source address of the frame
 129  *
 130  * The Recent Multicast Cache keeps track of the latest multicast frames that
 131  * have been received by a mesh interface and discards received multicast frames
 132  * that are found in the cache.
 133  */
 134 struct rmc_entry {
 135         struct list_head list;
 136         u32 seqnum;
 137         unsigned long exp_time;
 138         u8 sa[ETH_ALEN];
 139 };
 140
 141 struct mesh_rmc {
 142         struct rmc_entry bucket[RMC_BUCKETS];
 143         u32 idx_mask;
 144 };
 145
 146
 147 /* Mesh IEs constants */
 148 #define MESH_CFG_LEN            19
 149
 150 /*
 151  * MESH_CFG_COMP_LEN Includes:
 152  *      - Active path selection protocol ID.
 153  *      - Active path selection metric ID.
 154  *      - Congestion control mode identifier.
 155  *      - Channel precedence.
 156  * Does not include mesh capabilities, which may vary across nodes in the same
 157  * mesh
 158  */
 159 #define MESH_CFG_CMP_LEN        17
 160
 161 /* Default values, timeouts in ms */
 162 #define MESH_TTL                5
 163 #define MESH_MAX_RETR           3
 164 #define MESH_RET_T              100
 165 #define MESH_CONF_T             100
 166 #define MESH_HOLD_T             100
 167
 168 #define MESH_PATH_TIMEOUT       5000
 169 /* Minimum interval between two consecutive PREQs originated by the same
 170  * interface
 171  */
 172 #define MESH_PREQ_MIN_INT       10
 173 #define MESH_DIAM_TRAVERSAL_TIME 50
 174 /* Paths will be refreshed if they are closer than PATH_REFRESH_TIME to their
 175  * expiration
 176  */
 177 #define MESH_PATH_REFRESH_TIME                  1000
 178 #define MESH_MIN_DISCOVERY_TIMEOUT (2 * MESH_DIAM_TRAVERSAL_TIME)
 179
 180 #define MESH_MAX_PREQ_RETRIES 4
 181 #define MESH_PATH_EXPIRE (600 * HZ)
 182
 183 /* Default maximum number of established plinks per interface */
 184 #define MESH_MAX_ESTAB_PLINKS   32
 185
 186 /* Default maximum number of plinks per interface */
 187 #define MESH_MAX_PLINKS         256
 188
 189 /* Maximum number of paths per interface */
 190 #define MESH_MAX_MPATHS         1024
 191
 192 /* Pending ANA approval */
 193 #define PLINK_CATEGORY          30
 194 #define MESH_PATH_SEL_CATEGORY  32
 195
 196 /* Mesh Header Flags */
 197 #define IEEE80211S_FLAGS_AE     0x3
 198
 199 /* Public interfaces */
 200 /* Various */
 201 u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len);
 202 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr);
 203 int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
 204                 struct ieee80211_sub_if_data *sdata);
 205 int mesh_rmc_check(u8 *addr, struct ieee80211s_hdr *mesh_hdr,
 206                 struct ieee80211_sub_if_data *sdata);
 207 bool mesh_matches_local(struct ieee802_11_elems *ie,
 208                 struct ieee80211_sub_if_data *sdata);
 209 void mesh_ids_set_default(struct ieee80211_if_mesh *mesh);
 210 void mesh_mgmt_ies_add(struct sk_buff *skb,
 211                 struct ieee80211_sub_if_data *sdata);
 212 void mesh_rmc_free(struct ieee80211_sub_if_data *sdata);
 213 int mesh_rmc_init(struct ieee80211_sub_if_data *sdata);
 214 void ieee80211s_init(void);
 215 void ieee80211s_stop(void);
 216 void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata);
 217 ieee80211_rx_result
 218 ieee80211_mesh_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 219                        struct ieee80211_rx_status *rx_status);
 220 void ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata);
 221 void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata);
 222
 223 /* Mesh paths */
 224 int mesh_nexthop_lookup(struct sk_buff *skb,
 225                 struct ieee80211_sub_if_data *sdata);
 226 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata);
 227 struct mesh_path *mesh_path_lookup(u8 *dst,
 228                 struct ieee80211_sub_if_data *sdata);
 229 struct mesh_path *mesh_path_lookup_by_idx(int idx,
 230                 struct ieee80211_sub_if_data *sdata);
 231 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);
 232 void mesh_path_expire(struct ieee80211_sub_if_data *sdata);
 233 void mesh_path_flush(struct ieee80211_sub_if_data *sdata);
 234 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 235                 struct ieee80211_mgmt *mgmt, size_t len);
 236 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata);
 237 /* Mesh plinks */
 238 void mesh_neighbour_update(u8 *hw_addr, u64 rates,
 239                 struct ieee80211_sub_if_data *sdata, bool add);
 240 bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie);
 241 void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata);
 242 void mesh_plink_broken(struct sta_info *sta);
 243 void mesh_plink_deactivate(struct sta_info *sta);
 244 int mesh_plink_open(struct sta_info *sta);
 245 int mesh_plink_close(struct sta_info *sta);
 246 void mesh_plink_block(struct sta_info *sta);
 247 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
 248                          struct ieee80211_mgmt *mgmt, size_t len,
 249                          struct ieee80211_rx_status *rx_status);
 250
 251 /* Private interfaces */
 252 /* Mesh tables */
 253 struct mesh_table *mesh_table_alloc(int size_order);
 254 void mesh_table_free(struct mesh_table *tbl, bool free_leafs);
 255 struct mesh_table *mesh_table_grow(struct mesh_table *tbl);
 256 u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
 257                 struct mesh_table *tbl);
 258 /* Mesh paths */
 259 int mesh_path_error_tx(u8 *dest, __le32 dest_dsn, u8 *ra,
 260                 struct ieee80211_sub_if_data *sdata);
 261 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
 262 void mesh_path_flush_pending(struct mesh_path *mpath);
 263 void mesh_path_tx_pending(struct mesh_path *mpath);
 264 int mesh_pathtbl_init(void);
 265 void mesh_pathtbl_unregister(void);
 266 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata);
 267 void mesh_path_timer(unsigned long data);
 268 void mesh_path_flush_by_nexthop(struct sta_info *sta);
 269 void mesh_path_discard_frame(struct sk_buff *skb,
 270                 struct ieee80211_sub_if_data *sdata);
 271
 272 #ifdef CONFIG_MAC80211_MESH
 273 extern int mesh_allocated;
 274
 275 static inline int mesh_plink_free_count(struct ieee80211_sub_if_data *sdata)
 276 {
 277         return sdata->u.mesh.mshcfg.dot11MeshMaxPeerLinks -
 278                atomic_read(&sdata->u.mesh.mshstats.estab_plinks);
 279 }
 280
 281 static inline bool mesh_plink_availables(struct ieee80211_sub_if_data *sdata)
 282 {
 283         return (min_t(long, mesh_plink_free_count(sdata),
 284                    MESH_MAX_PLINKS - sdata->local->num_sta)) > 0;
 285 }
 286
 287 static inline void mesh_path_activate(struct mesh_path *mpath)
 288 {
 289         mpath->flags |= MESH_PATH_ACTIVE | MESH_PATH_RESOLVED;
 290 }
 291
 292 #define for_each_mesh_entry(x, p, node, i) \
 293         for (i = 0; i <= x->hash_mask; i++) \
 294                 hlist_for_each_entry_rcu(node, p, &x->hash_buckets[i], list)
 295
 296 void ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local);
 297
 298 #else
 299 #define mesh_allocated  0
 300 static inline void
 301 ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local) {}
 302 #endif
 303
 304 #endif /* IEEE80211S_H */