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 "ieee80211_i.h"
  17
  18
  19 /* Data structures */
  20
  21 /**
  22  * enum mesh_path_flags - mac80211 mesh path flags
  23  *
  24  *
  25  *
  26  * @MESH_PATH_ACTIVE: the mesh path is can be used for forwarding
  27  * @MESH_PATH_RESOLVED: the discovery process is running for this mesh path
  28  * @MESH_PATH_DSN_VALID: the mesh path contains a valid destination sequence
  29  *      number
  30  * @MESH_PATH_FIXED: the mesh path has been manually set and should not be
  31  *      modified
  32  * @MESH_PATH_RESOLVED: the mesh path can has been resolved
  33  *
  34  * MESH_PATH_RESOLVED and MESH_PATH_DELETE are used by the mesh path timer to
  35  * decide when to stop or cancel the mesh path discovery.
  36  */
  37 enum mesh_path_flags {
  38         MESH_PATH_ACTIVE =      BIT(0),
  39         MESH_PATH_RESOLVING =   BIT(1),
  40         MESH_PATH_DSN_VALID =   BIT(2),
  41         MESH_PATH_FIXED =       BIT(3),
  42         MESH_PATH_RESOLVED =    BIT(4),
  43 };
  44
  45 /**
  46  * struct mesh_path - mac80211 mesh path structure
  47  *
  48  * @dst: mesh path destination mac address
  49  * @dev: mesh path device
  50  * @next_hop: mesh neighbor to which frames for this destination will be
  51  *      forwarded
  52  * @timer: mesh path discovery timer
  53  * @frame_queue: pending queue for frames sent to this destination while the
  54  *      path is unresolved
  55  * @dsn: destination sequence number of the destination
  56  * @metric: current metric to this destination
  57  * @hop_count: hops to destination
  58  * @exp_time: in jiffies, when the path will expire or when it expired
  59  * @discovery_timeout: timeout (lapse in jiffies) used for the last discovery
  60  *      retry
  61  * @discovery_retries: number of discovery retries
  62  * @flags: mesh path flags, as specified on &enum mesh_path_flags
  63  * @state_lock: mesh pat state lock
  64  *
  65  *
  66  * The combination of dst and dev is unique in the mesh path table. Since the
  67  * next_hop STA is only protected by RCU as well, deleting the STA must also
  68  * remove/substitute the mesh_path structure and wait until that is no longer
  69  * reachable before destroying the STA completely.
  70  */
  71 struct mesh_path {
  72         u8 dst[ETH_ALEN];
  73         struct net_device *dev;
  74         struct sta_info *next_hop;
  75         struct timer_list timer;
  76         struct sk_buff_head frame_queue;
  77         struct rcu_head rcu;
  78         u32 dsn;
  79         u32 metric;
  80         u8 hop_count;
  81         unsigned long exp_time;
  82         u32 discovery_timeout;
  83         u8 discovery_retries;
  84         enum mesh_path_flags flags;
  85         spinlock_t state_lock;
  86 };
  87
  88 /**
  89  * struct mesh_table
  90  *
  91  * @hash_buckets: array of hash buckets of the table
  92  * @hashwlock: array of locks to protect write operations, one per bucket
  93  * @hash_mask: 2^size_order - 1, used to compute hash idx
  94  * @hash_rnd: random value used for hash computations
  95  * @entries: number of entries in the table
  96  * @free_node: function to free nodes of the table
  97  * @copy_node: fuction to copy nodes of the table
  98  * @size_order: determines size of the table, there will be 2^size_order hash
  99  *      buckets
 100  * @mean_chain_len: maximum average length for the hash buckets' list, if it is
 101  *      reached, the table will grow
 102  */
 103 struct mesh_table {
 104         /* Number of buckets will be 2^N */
 105         struct hlist_head *hash_buckets;
 106         spinlock_t *hashwlock;          /* One per bucket, for add/del */
 107         unsigned int hash_mask;         /* (2^size_order) - 1 */
 108         __u32 hash_rnd;                 /* Used for hash generation */
 109         atomic_t entries;               /* Up to MAX_MESH_NEIGHBOURS */
 110         void (*free_node) (struct hlist_node *p, bool free_leafs);
 111         void (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);
 112         int size_order;
 113         int mean_chain_len;
 114 };
 115
 116 /* Recent multicast cache */
 117 /* RMC_BUCKETS must be a power of 2, maximum 256 */
 118 #define RMC_BUCKETS             256
 119 #define RMC_QUEUE_MAX_LEN       4
 120 #define RMC_TIMEOUT             (3 * HZ)
 121
 122 /**
 123  * struct rmc_entry - entry in the Recent Multicast Cache
 124  *
 125  * @seqnum: mesh sequence number of the frame
 126  * @exp_time: expiration time of the entry, in jiffies
 127  * @sa: source address of the frame
 128  *
 129  * The Recent Multicast Cache keeps track of the latest multicast frames that
 130  * have been received by a mesh interface and discards received multicast frames
 131  * that are found in the cache.
 132  */
 133 struct rmc_entry {
 134         struct list_head list;
 135         u32 seqnum;
 136         unsigned long exp_time;
 137         u8 sa[ETH_ALEN];
 138 };
 139
 140 struct mesh_rmc {
 141         struct rmc_entry bucket[RMC_BUCKETS];
 142         u8 idx_mask;
 143 };
 144
 145
 146 /* Mesh IEs constants */
 147 #define MESH_CFG_LEN            19
 148
 149 /*
 150  * MESH_CFG_COMP_LEN Includes:
 151  *      - Active path selection protocol ID.
 152  *      - Active path selection metric ID.
 153  *      - Congestion control mode identifier.
 154  *      - Channel precedence.
 155  * Does not include mesh capabilities, which may vary across nodes in the same
 156  * mesh
 157  */
 158 #define MESH_CFG_CMP_LEN        17
 159
 160 /* Default values, timeouts in ms */
 161 #define MESH_TTL                5
 162 #define MESH_MAX_RETR           3
 163 #define MESH_RET_T              100
 164 #define MESH_CONF_T             100
 165 #define MESH_HOLD_T             100
 166
 167 #define MESH_PATH_TIMEOUT       5000
 168 /* Minimum interval between two consecutive PREQs originated by the same
 169  * interface
 170  */
 171 #define MESH_PREQ_MIN_INT       10
 172 #define MESH_DIAM_TRAVERSAL_TIME 50
 173 /* Paths will be refreshed if they are closer than PATH_REFRESH_TIME to their
 174  * expiration
 175  */
 176 #define MESH_PATH_REFRESH_TIME                  1000
 177 #define MESH_MIN_DISCOVERY_TIMEOUT (2 * MESH_DIAM_TRAVERSAL_TIME)
 178
 179 #define MESH_MAX_PREQ_RETRIES 4
 180 #define MESH_PATH_EXPIRE (600 * HZ)
 181
 182 /* Default maximum number of established plinks per interface */
 183 #define MESH_MAX_ESTAB_PLINKS   32
 184
 185 /* Default maximum number of plinks per interface */
 186 #define MESH_MAX_PLINKS         256
 187
 188 /* Maximum number of paths per interface */
 189 #define MESH_MAX_MPATHS         1024
 190
 191 /* Pending ANA approval */
 192 #define PLINK_CATEGORY          30
 193 #define MESH_PATH_SEL_CATEGORY  32
 194
 195 /* Mesh Header Flags */
 196 #define IEEE80211S_FLAGS_AE     0x3
 197
 198 /* Public interfaces */
 199 /* Various */
 200 u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len);
 201 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr);
 202 int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
 203                 struct ieee80211_sub_if_data *sdata);
 204 int mesh_rmc_check(u8 *addr, struct ieee80211s_hdr *mesh_hdr,
 205                 struct net_device *dev);
 206 bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev);
 207 void mesh_ids_set_default(struct ieee80211_if_sta *sta);
 208 void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev);
 209 void mesh_rmc_free(struct net_device *dev);
 210 int mesh_rmc_init(struct net_device *dev);
 211 void ieee80211s_init(void);
 212 void ieee80211s_stop(void);
 213 void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata);
 214
 215 /* Mesh paths */
 216 int mesh_nexthop_lookup(u8 *next_hop, struct sk_buff *skb,
 217                 struct net_device *dev);
 218 void mesh_path_start_discovery(struct net_device *dev);
 219 struct mesh_path *mesh_path_lookup(u8 *dst, struct net_device *dev);
 220 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct net_device *dev);
 221 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);
 222 void mesh_path_expire(struct net_device *dev);
 223 void mesh_path_flush(struct net_device *dev);
 224 void mesh_rx_path_sel_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
 225                 size_t len);
 226 int mesh_path_add(u8 *dst, struct net_device *dev);
 227 /* Mesh plinks */
 228 void mesh_neighbour_update(u8 *hw_addr, u64 rates, struct net_device *dev,
 229                 bool add);
 230 bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,
 231                               struct net_device *dev);
 232 void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata);
 233 void mesh_plink_broken(struct sta_info *sta);
 234 void mesh_plink_deactivate(struct sta_info *sta);
 235 int mesh_plink_open(struct sta_info *sta);
 236 int mesh_plink_close(struct sta_info *sta);
 237 void mesh_plink_block(struct sta_info *sta);
 238 void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
 239                          size_t len, struct ieee80211_rx_status *rx_status);
 240
 241 /* Private interfaces */
 242 /* Mesh tables */
 243 struct mesh_table *mesh_table_alloc(int size_order);
 244 void mesh_table_free(struct mesh_table *tbl, bool free_leafs);
 245 struct mesh_table *mesh_table_grow(struct mesh_table *tbl);
 246 u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl);
 247 /* Mesh paths */
 248 int mesh_path_error_tx(u8 *dest, __le32 dest_dsn, u8 *ra,
 249                 struct net_device *dev);
 250 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
 251 void mesh_path_flush_pending(struct mesh_path *mpath);
 252 void mesh_path_tx_pending(struct mesh_path *mpath);
 253 int mesh_pathtbl_init(void);
 254 void mesh_pathtbl_unregister(void);
 255 int mesh_path_del(u8 *addr, struct net_device *dev);
 256 void mesh_path_timer(unsigned long data);
 257 void mesh_path_flush_by_nexthop(struct sta_info *sta);
 258 void mesh_path_discard_frame(struct sk_buff *skb, struct net_device *dev);
 259
 260 #ifdef CONFIG_MAC80211_MESH
 261 extern int mesh_allocated;
 262
 263 static inline int mesh_plink_free_count(struct ieee80211_sub_if_data *sdata)
 264 {
 265         return sdata->u.sta.mshcfg.dot11MeshMaxPeerLinks -
 266                atomic_read(&sdata->u.sta.mshstats.estab_plinks);
 267 }
 268
 269 static inline bool mesh_plink_availables(struct ieee80211_sub_if_data *sdata)
 270 {
 271         return (min_t(long, mesh_plink_free_count(sdata),
 272                    MESH_MAX_PLINKS - sdata->local->num_sta)) > 0;
 273 }
 274
 275 static inline void mesh_path_activate(struct mesh_path *mpath)
 276 {
 277         mpath->flags |= MESH_PATH_ACTIVE | MESH_PATH_RESOLVED;
 278 }
 279
 280 #define for_each_mesh_entry(x, p, node, i) \
 281         for (i = 0; i <= x->hash_mask; i++) \
 282                 hlist_for_each_entry_rcu(node, p, &x->hash_buckets[i], list)
 283
 284 #else
 285 #define mesh_allocated  0
 286 #endif
 287
 288 #define MESH_PREQ(skb)  (skb->cb + 30)
 289
 290 #endif /* IEEE80211S_H */