mac80211: mesh function and data structures definitions

Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mesh.h

+/*
+ * Copyright (c) 2008 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 "ieee80211_i.h"
+#include <linux/jhash.h>
+
+extern int mesh_allocated;
+
+/* Data structures */
+
+/**
+ * enum mesh_path_flags - mac80211 mesh path flags
+ *
+ *
+ *
+ * @MESH_PATH_ACTIVE: the mesh path is can be used for forwarding
+ * @MESH_PATH_RESOLVED: the discovery process is running for this mesh path
+ * @MESH_PATH_DSN_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_DELETE: the mesh path is scheduled to be deleted
+ *
+ * MESH_PATH_RESOLVED and MESH_PATH_DELETE are 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_DSN_VALID =	BIT(2),
+	MESH_PATH_FIXED	=	BIT(3),
+	MESH_PATH_RESOLVED =	BIT(4),
+	MESH_PATH_DELETE =	BIT(5),
+};
+
+/**
+ * struct mesh_path - mac80211 mesh path structure
+ *
+ * @dst: mesh path destination mac address
+ * @dev: mesh path device
+ * @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
+ * @dsn: destination sequence number of the destination
+ * @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 pat state lock
+ *
+ *
+ * The combination of dst and dev is unique in the mesh path table. A reference
+ * to the next_hop sta will be kept and in case this sta is removed, the
+ * mesh_path structure must be also removed or substitued in a rcu safe way
+ */
+struct mesh_path {
+	u8 dst[ETH_ALEN];
+	struct net_device *dev;
+	struct sta_info *next_hop;
+	struct timer_list timer;
+	struct sk_buff_head frame_queue;
+	struct rcu_head rcu;
+	u32 dsn;
+	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: fuction 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
+ */
+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);
+	void (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);
+	int size_order;
+	int mean_chain_len;
+};
+
+/* 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];
+	u8 idx_mask;
+};
+
+
+/* Mesh IEs constants */
+#define MESH_CFG_LEN		19
+
+/*
+ * MESH_CFG_COMP_LEN Includes:
+ * 	- Active path selection protocol ID.
+ * 	- Active path selection metric ID.
+ * 	- Congestion control mode identifier.
+ * 	- Channel precedence.
+ * Does not include mesh capabilities, which may vary across nodes in the same
+ * mesh
+ */
+#define MESH_CFG_CMP_LEN 	17
+
+/* Default values, timeouts in ms */
+#define MESH_TTL 		5
+#define MESH_MAX_RETR	 	3
+#define MESH_RET_T 		100
+#define MESH_CONF_T 		100
+#define MESH_HOLD_T 		100
+
+#define MESH_PATH_TIMEOUT	5000
+/* Minimum interval between two consecutive PREQs originated by the same
+ * interface
+ */
+#define MESH_PREQ_MIN_INT	10
+#define MESH_DIAM_TRAVERSAL_TIME 50
+/* Paths will be refreshed if they are closer than PATH_REFRESH_TIME to their
+ * expiration
+ */
+#define MESH_PATH_REFRESH_TIME			1000
+#define MESH_MIN_DISCOVERY_TIMEOUT (2 * MESH_DIAM_TRAVERSAL_TIME)
+
+#define MESH_MAX_PREQ_RETRIES 4
+#define MESH_PATH_EXPIRE (600 * HZ)
+
+/* Default maximum number of established plinks per interface */
+#define MESH_MAX_ESTAB_PLINKS	32
+
+/* 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 PLINK_CATEGORY		30
+#define MESH_PATH_SEL_CATEGORY	32
+
+/* Mesh Header Flags */
+#define IEEE80211S_FLAGS_AE	0x3
+
+/* Public interfaces */
+/* Various */
+u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len);
+int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr);
+int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
+		struct ieee80211_sub_if_data *sdata);
+int mesh_rmc_check(u8 *addr, struct ieee80211s_hdr *mesh_hdr,
+		struct net_device *dev);
+bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev);
+void mesh_ids_set_default(struct ieee80211_if_sta *sta);
+void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev);
+void mesh_rmc_free(struct net_device *dev);
+int mesh_rmc_init(struct net_device *dev);
+void ieee80211s_init(void);
+void ieee80211s_stop(void);
+/* Mesh paths */
+int mesh_nexthop_lookup(u8 *next_hop, struct sk_buff *skb,
+		struct net_device *dev);
+void mesh_path_start_discovery(struct net_device *dev);
+struct mesh_path *mesh_path_lookup(u8 *dst, struct net_device *dev);
+struct mesh_path *mesh_path_lookup_by_idx(int idx, struct net_device *dev);
+void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);
+void mesh_path_expire(struct net_device *dev);
+void mesh_path_flush(struct net_device *dev);
+void mesh_rx_path_sel_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
+		size_t len);
+int mesh_path_add(u8 *dst, struct net_device *dev);
+/* Mesh plinks */
+void mesh_neighbour_update(u8 *hw_addr, u64 rates, struct net_device *dev,
+		bool add);
+bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,
+			      struct net_device *dev);
+void mesh_accept_plinks_update(struct net_device *dev);
+struct sta_info *mesh_plink_add(u8 *hw_addr, u64 rates, struct net_device *dev);
+void mesh_plink_broken(struct sta_info *sta);
+void mesh_plink_deactivate(struct sta_info *sta);
+int mesh_plink_open(struct sta_info *sta);
+int mesh_plink_close(struct sta_info *sta);
+void mesh_plink_block(struct sta_info *sta);
+void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
+			 size_t len, struct ieee80211_rx_status *rx_status);
+
+/* Private interfaces */
+/* Mesh tables */
+struct mesh_table *mesh_table_alloc(int size_order);
+void mesh_table_free(struct mesh_table *tbl, bool free_leafs);
+struct mesh_table *mesh_table_grow(struct mesh_table *tbl);
+u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl);
+/* Mesh paths */
+int mesh_path_error_tx(u8 *dest, __le32 dest_dsn, u8 *ra,
+		struct net_device *dev);
+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 net_device *dev);
+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 net_device *dev);
+
+static inline int mesh_plink_free_count(struct ieee80211_sub_if_data *sdata)
+{
+	return sdata->u.sta.mshcfg.dot11MeshMaxPeerLinks -
+	       atomic_read(&sdata->u.sta.mshstats.estab_plinks);
+}
+
+static inline bool mesh_plink_availables(struct ieee80211_sub_if_data *sdata)
+{
+	return (min(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;
+}
+
+#define for_each_mesh_entry(x, p, node, i) \
+	for (i = 0; i <= x->hash_mask; i++) \
+		hlist_for_each_entry_rcu(node, p, &x->hash_buckets[i], list)
+
+#define MESH_PREQ(skb)	(skb->cb + 30)
+
+#endif /* IEEE80211S_H */