/*

   * Copyright (c) 2008, 2009 open80211s Ltd.

   * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
   *             Javier Cardona <javier@cozybit.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #ifndef IEEE80211S_H
  #define IEEE80211S_H

  #include <linux/types.h>

  #include <linux/jhash.h>

  #include <asm/unaligned.h>

  #include "ieee80211_i.h"

  
  /* Data structures */
  
  /**
   * enum mesh_path_flags - mac80211 mesh path flags
   *
   *
   *

   * @MESH_PATH_ACTIVE: the mesh path can be used for forwarding
   * @MESH_PATH_RESOLVING: the discovery process is running for this mesh path

   * @MESH_PATH_SN_VALID: the mesh path contains a valid destination sequence

   * 	number
   * @MESH_PATH_FIXED: the mesh path has been manually set and should not be
   * 	modified
   * @MESH_PATH_RESOLVED: the mesh path can has been resolved

   *

   * MESH_PATH_RESOLVED is used by the mesh path timer to

   * decide when to stop or cancel the mesh path discovery.
   */
  enum mesh_path_flags {
  	MESH_PATH_ACTIVE =	BIT(0),
  	MESH_PATH_RESOLVING =	BIT(1),

  	MESH_PATH_SN_VALID =	BIT(2),

  	MESH_PATH_FIXED	=	BIT(3),
  	MESH_PATH_RESOLVED =	BIT(4),

  };
  
  /**

   * enum mesh_deferred_task_flags - mac80211 mesh deferred tasks
   *
   *
   *
   * @MESH_WORK_HOUSEKEEPING: run the periodic mesh housekeeping tasks
   * @MESH_WORK_GROW_MPATH_TABLE: the mesh path table is full and needs
   * to grow.
   * @MESH_WORK_GROW_MPP_TABLE: the mesh portals table is full and needs to
   * grow

   * @MESH_WORK_ROOT: the mesh root station needs to send a frame

   */
  enum mesh_deferred_task_flags {
  	MESH_WORK_HOUSEKEEPING,
  	MESH_WORK_GROW_MPATH_TABLE,
  	MESH_WORK_GROW_MPP_TABLE,

  	MESH_WORK_ROOT,

  };
  
  /**

   * struct mesh_path - mac80211 mesh path structure
   *
   * @dst: mesh path destination mac address

   * @sdata: mesh subif

   * @next_hop: mesh neighbor to which frames for this destination will be
   * 	forwarded
   * @timer: mesh path discovery timer
   * @frame_queue: pending queue for frames sent to this destination while the
   * 	path is unresolved

   * @sn: target sequence number

   * @metric: current metric to this destination
   * @hop_count: hops to destination
   * @exp_time: in jiffies, when the path will expire or when it expired
   * @discovery_timeout: timeout (lapse in jiffies) used for the last discovery
   * 	retry
   * @discovery_retries: number of discovery retries
   * @flags: mesh path flags, as specified on &enum mesh_path_flags

   * @state_lock: mesh path state lock

   *
   *

   * The combination of dst and sdata is unique in the mesh path table. Since the

   * next_hop STA is only protected by RCU as well, deleting the STA must also
   * remove/substitute the mesh_path structure and wait until that is no longer
   * reachable before destroying the STA completely.

   */
  struct mesh_path {
  	u8 dst[ETH_ALEN];

  	u8 mpp[ETH_ALEN];	/* used for MPP or MAP */

  	struct ieee80211_sub_if_data *sdata;

  	struct sta_info __rcu *next_hop;

  	struct timer_list timer;
  	struct sk_buff_head frame_queue;
  	struct rcu_head rcu;

  	u32 sn;

  	u32 metric;
  	u8 hop_count;
  	unsigned long exp_time;
  	u32 discovery_timeout;
  	u8 discovery_retries;
  	enum mesh_path_flags flags;
  	spinlock_t state_lock;
  };
  
  /**
   * struct mesh_table
   *
   * @hash_buckets: array of hash buckets of the table
   * @hashwlock: array of locks to protect write operations, one per bucket
   * @hash_mask: 2^size_order - 1, used to compute hash idx
   * @hash_rnd: random value used for hash computations
   * @entries: number of entries in the table
   * @free_node: function to free nodes of the table

   * @copy_node: function to copy nodes of the table

   * @size_order: determines size of the table, there will be 2^size_order hash
   *	buckets
   * @mean_chain_len: maximum average length for the hash buckets' list, if it is
   *	reached, the table will grow

   * rcu_head: RCU head to free the table

   */
  struct mesh_table {
  	/* Number of buckets will be 2^N */
  	struct hlist_head *hash_buckets;
  	spinlock_t *hashwlock;		/* One per bucket, for add/del */
  	unsigned int hash_mask;		/* (2^size_order) - 1 */
  	__u32 hash_rnd;			/* Used for hash generation */
  	atomic_t entries;		/* Up to MAX_MESH_NEIGHBOURS */
  	void (*free_node) (struct hlist_node *p, bool free_leafs);

  	int (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);

  	int size_order;
  	int mean_chain_len;

  
  	struct rcu_head rcu_head;

  };
  
  /* Recent multicast cache */
  /* RMC_BUCKETS must be a power of 2, maximum 256 */
  #define RMC_BUCKETS		256
  #define RMC_QUEUE_MAX_LEN	4
  #define RMC_TIMEOUT		(3 * HZ)
  
  /**
   * struct rmc_entry - entry in the Recent Multicast Cache
   *
   * @seqnum: mesh sequence number of the frame
   * @exp_time: expiration time of the entry, in jiffies
   * @sa: source address of the frame
   *
   * The Recent Multicast Cache keeps track of the latest multicast frames that
   * have been received by a mesh interface and discards received multicast frames
   * that are found in the cache.
   */
  struct rmc_entry {
  	struct list_head list;
  	u32 seqnum;
  	unsigned long exp_time;
  	u8 sa[ETH_ALEN];
  };
  
  struct mesh_rmc {
  	struct rmc_entry bucket[RMC_BUCKETS];

  	u32 idx_mask;

  };

  #define MESH_DEFAULT_BEACON_INTERVAL		1000 	/* in 1024 us units */

  #define MESH_PATH_EXPIRE (600 * HZ)

  /* Default maximum number of plinks per interface */
  #define MESH_MAX_PLINKS		256
  
  /* Maximum number of paths per interface */
  #define MESH_MAX_MPATHS		1024
  
  /* Pending ANA approval */

  #define MESH_PATH_SEL_ACTION	0

  /* PERR reason codes */
  #define PEER_RCODE_UNSPECIFIED  11
  #define PERR_RCODE_NO_ROUTE     12
  #define PERR_RCODE_DEST_UNREACH 13

  /* Public interfaces */
  /* Various */

  int ieee80211_fill_mesh_addresses(struct ieee80211_hdr *hdr, __le16 *fc,

  				  const u8 *da, const u8 *sa);

  int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,

  		struct ieee80211_sub_if_data *sdata, char *addr4or5,
  		char *addr6);

  int mesh_rmc_check(u8 *addr, struct ieee80211s_hdr *mesh_hdr,

  		struct ieee80211_sub_if_data *sdata);
  bool mesh_matches_local(struct ieee802_11_elems *ie,
  		struct ieee80211_sub_if_data *sdata);

  void mesh_ids_set_default(struct ieee80211_if_mesh *mesh);

  void mesh_mgmt_ies_add(struct sk_buff *skb,
  		struct ieee80211_sub_if_data *sdata);
  void mesh_rmc_free(struct ieee80211_sub_if_data *sdata);
  int mesh_rmc_init(struct ieee80211_sub_if_data *sdata);

  void ieee80211s_init(void);

  void ieee80211s_update_metric(struct ieee80211_local *local,
  		struct sta_info *stainfo, struct sk_buff *skb);

  void ieee80211s_stop(void);

  void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata);

  void ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata);
  void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata);

  void ieee80211_mesh_root_setup(struct ieee80211_if_mesh *ifmsh);

  /* Mesh paths */

  int mesh_nexthop_lookup(struct sk_buff *skb,
  		struct ieee80211_sub_if_data *sdata);
  void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata);
  struct mesh_path *mesh_path_lookup(u8 *dst,
  		struct ieee80211_sub_if_data *sdata);

  struct mesh_path *mpp_path_lookup(u8 *dst,
  				  struct ieee80211_sub_if_data *sdata);
  int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata);

  struct mesh_path *mesh_path_lookup_by_idx(int idx,
  		struct ieee80211_sub_if_data *sdata);

  void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);

  void mesh_path_expire(struct ieee80211_sub_if_data *sdata);
  void mesh_path_flush(struct ieee80211_sub_if_data *sdata);
  void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
  		struct ieee80211_mgmt *mgmt, size_t len);
  int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata);

  /* Mesh plinks */

  void mesh_neighbour_update(u8 *hw_addr, u32 rates,

  		struct ieee80211_sub_if_data *sdata,
  		struct ieee802_11_elems *ie);

  bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie);

  void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata);

  void mesh_plink_broken(struct sta_info *sta);
  void mesh_plink_deactivate(struct sta_info *sta);
  int mesh_plink_open(struct sta_info *sta);

  void mesh_plink_block(struct sta_info *sta);

  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
  			 struct ieee80211_mgmt *mgmt, size_t len,
  			 struct ieee80211_rx_status *rx_status);

  
  /* Private interfaces */
  /* Mesh tables */

  void mesh_mpath_table_grow(void);
  void mesh_mpp_table_grow(void);

  /* Mesh paths */

  int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn, __le16 target_rcode,

  		       const u8 *ra, struct ieee80211_sub_if_data *sdata);

  void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
  void mesh_path_flush_pending(struct mesh_path *mpath);
  void mesh_path_tx_pending(struct mesh_path *mpath);
  int mesh_pathtbl_init(void);
  void mesh_pathtbl_unregister(void);

  int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata);

  void mesh_path_timer(unsigned long data);
  void mesh_path_flush_by_nexthop(struct sta_info *sta);

  void mesh_path_discard_frame(struct sk_buff *skb,
  		struct ieee80211_sub_if_data *sdata);

  void mesh_path_quiesce(struct ieee80211_sub_if_data *sdata);
  void mesh_path_restart(struct ieee80211_sub_if_data *sdata);

  void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata);

  extern int mesh_paths_generation;

  #ifdef CONFIG_MAC80211_MESH
  extern int mesh_allocated;

  static inline int mesh_plink_free_count(struct ieee80211_sub_if_data *sdata)
  {

  	return sdata->u.mesh.mshcfg.dot11MeshMaxPeerLinks -
  	       atomic_read(&sdata->u.mesh.mshstats.estab_plinks);

  }
  
  static inline bool mesh_plink_availables(struct ieee80211_sub_if_data *sdata)
  {

  	return (min_t(long, mesh_plink_free_count(sdata),

  		   MESH_MAX_PLINKS - sdata->local->num_sta)) > 0;
  }
  
  static inline void mesh_path_activate(struct mesh_path *mpath)
  {
  	mpath->flags |= MESH_PATH_ACTIVE | MESH_PATH_RESOLVED;
  }

  static inline bool mesh_path_sel_is_hwmp(struct ieee80211_sub_if_data *sdata)
  {
  	return sdata->u.mesh.mesh_pp_id == IEEE80211_PATH_PROTOCOL_HWMP;
  }

  void ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local);

  void ieee80211_mesh_quiesce(struct ieee80211_sub_if_data *sdata);
  void ieee80211_mesh_restart(struct ieee80211_sub_if_data *sdata);
  void mesh_plink_quiesce(struct sta_info *sta);
  void mesh_plink_restart(struct sta_info *sta);

  #else
  #define mesh_allocated	0

  static inline void
  ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local) {}

  static inline void ieee80211_mesh_quiesce(struct ieee80211_sub_if_data *sdata)
  {}
  static inline void ieee80211_mesh_restart(struct ieee80211_sub_if_data *sdata)
  {}
  static inline void mesh_plink_quiesce(struct sta_info *sta) {}
  static inline void mesh_plink_restart(struct sta_info *sta) {}

  static inline bool mesh_path_sel_is_hwmp(struct ieee80211_sub_if_data *sdata)
  { return false; }

  #endif

  #endif /* IEEE80211S_H */