The patch ("mac80211: Use correct sign for mesh active path
refresh.") was actually a bug.  Reverted it and improved the
explanation of how mesh path refresh works.
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Andrey Yurovsky <andrey@cozybit.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
		
	
			
		
			
				
	
	
		
			347 lines
		
	
	
	
		
			12 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			347 lines
		
	
	
	
		
			12 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (c) 2008, 2009 open80211s Ltd.
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 * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
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 *             Javier Cardona <javier@cozybit.com>
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License version 2 as
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 * published by the Free Software Foundation.
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 */
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#ifndef IEEE80211S_H
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#define IEEE80211S_H
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#include <linux/types.h>
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#include <linux/jhash.h>
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#include <asm/unaligned.h>
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#include "ieee80211_i.h"
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/* Data structures */
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/**
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 * enum mesh_path_flags - mac80211 mesh path flags
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 *
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 *
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 *
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 * @MESH_PATH_ACTIVE: the mesh path can be used for forwarding
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 * @MESH_PATH_RESOLVING: the discovery process is running for this mesh path
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 * @MESH_PATH_SN_VALID: the mesh path contains a valid destination sequence
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 * 	number
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 * @MESH_PATH_FIXED: the mesh path has been manually set and should not be
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 * 	modified
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 * @MESH_PATH_RESOLVED: the mesh path can has been resolved
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 *
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 * MESH_PATH_RESOLVED is used by the mesh path timer to
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 * decide when to stop or cancel the mesh path discovery.
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 */
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enum mesh_path_flags {
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	MESH_PATH_ACTIVE =	BIT(0),
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	MESH_PATH_RESOLVING =	BIT(1),
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	MESH_PATH_SN_VALID =	BIT(2),
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	MESH_PATH_FIXED	=	BIT(3),
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	MESH_PATH_RESOLVED =	BIT(4),
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};
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/**
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 * enum mesh_deferred_task_flags - mac80211 mesh deferred tasks
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 *
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 *
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 *
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 * @MESH_WORK_HOUSEKEEPING: run the periodic mesh housekeeping tasks
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 * @MESH_WORK_GROW_MPATH_TABLE: the mesh path table is full and needs
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 * to grow.
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 * @MESH_WORK_GROW_MPP_TABLE: the mesh portals table is full and needs to
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 * grow
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 * @MESH_WORK_ROOT: the mesh root station needs to send a frame
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 */
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enum mesh_deferred_task_flags {
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	MESH_WORK_HOUSEKEEPING,
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	MESH_WORK_GROW_MPATH_TABLE,
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	MESH_WORK_GROW_MPP_TABLE,
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	MESH_WORK_ROOT,
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};
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/**
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 * struct mesh_path - mac80211 mesh path structure
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 *
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 * @dst: mesh path destination mac address
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 * @sdata: mesh subif
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 * @next_hop: mesh neighbor to which frames for this destination will be
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 * 	forwarded
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 * @timer: mesh path discovery timer
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 * @frame_queue: pending queue for frames sent to this destination while the
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 * 	path is unresolved
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 * @sn: target sequence number
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 * @metric: current metric to this destination
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 * @hop_count: hops to destination
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 * @exp_time: in jiffies, when the path will expire or when it expired
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 * @discovery_timeout: timeout (lapse in jiffies) used for the last discovery
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 * 	retry
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 * @discovery_retries: number of discovery retries
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 * @flags: mesh path flags, as specified on &enum mesh_path_flags
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 * @state_lock: mesh path state lock
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 *
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 *
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 * The combination of dst and sdata is unique in the mesh path table. Since the
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 * next_hop STA is only protected by RCU as well, deleting the STA must also
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 * remove/substitute the mesh_path structure and wait until that is no longer
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 * reachable before destroying the STA completely.
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 */
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struct mesh_path {
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	u8 dst[ETH_ALEN];
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	u8 mpp[ETH_ALEN];	/* used for MPP or MAP */
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	struct ieee80211_sub_if_data *sdata;
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	struct sta_info *next_hop;
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	struct timer_list timer;
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	struct sk_buff_head frame_queue;
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	struct rcu_head rcu;
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	u32 sn;
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	u32 metric;
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	u8 hop_count;
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	unsigned long exp_time;
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	u32 discovery_timeout;
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	u8 discovery_retries;
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	enum mesh_path_flags flags;
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	spinlock_t state_lock;
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};
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/**
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 * struct mesh_table
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 *
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 * @hash_buckets: array of hash buckets of the table
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 * @hashwlock: array of locks to protect write operations, one per bucket
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 * @hash_mask: 2^size_order - 1, used to compute hash idx
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 * @hash_rnd: random value used for hash computations
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 * @entries: number of entries in the table
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 * @free_node: function to free nodes of the table
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 * @copy_node: fuction to copy nodes of the table
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 * @size_order: determines size of the table, there will be 2^size_order hash
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 *	buckets
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 * @mean_chain_len: maximum average length for the hash buckets' list, if it is
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 *	reached, the table will grow
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 */
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struct mesh_table {
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	/* Number of buckets will be 2^N */
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	struct hlist_head *hash_buckets;
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	spinlock_t *hashwlock;		/* One per bucket, for add/del */
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	unsigned int hash_mask;		/* (2^size_order) - 1 */
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	__u32 hash_rnd;			/* Used for hash generation */
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	atomic_t entries;		/* Up to MAX_MESH_NEIGHBOURS */
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	void (*free_node) (struct hlist_node *p, bool free_leafs);
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	int (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);
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	int size_order;
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	int mean_chain_len;
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};
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/* Recent multicast cache */
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/* RMC_BUCKETS must be a power of 2, maximum 256 */
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#define RMC_BUCKETS		256
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#define RMC_QUEUE_MAX_LEN	4
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#define RMC_TIMEOUT		(3 * HZ)
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/**
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 * struct rmc_entry - entry in the Recent Multicast Cache
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 *
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 * @seqnum: mesh sequence number of the frame
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 * @exp_time: expiration time of the entry, in jiffies
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 * @sa: source address of the frame
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 *
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 * The Recent Multicast Cache keeps track of the latest multicast frames that
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 * have been received by a mesh interface and discards received multicast frames
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 * that are found in the cache.
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 */
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struct rmc_entry {
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	struct list_head list;
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	u32 seqnum;
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	unsigned long exp_time;
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	u8 sa[ETH_ALEN];
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};
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struct mesh_rmc {
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	struct rmc_entry bucket[RMC_BUCKETS];
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	u32 idx_mask;
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};
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/*
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 * MESH_CFG_COMP_LEN Includes:
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 * 	- Active path selection protocol ID.
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 * 	- Active path selection metric ID.
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 * 	- Congestion control mode identifier.
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 * 	- Channel precedence.
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 * Does not include mesh capabilities, which may vary across nodes in the same
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 * mesh
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 */
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#define MESH_CFG_CMP_LEN 	(IEEE80211_MESH_CONFIG_LEN - 2)
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/* Default values, timeouts in ms */
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#define MESH_TTL 		31
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#define MESH_MAX_RETR	 	3
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#define MESH_RET_T 		100
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#define MESH_CONF_T 		100
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#define MESH_HOLD_T 		100
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#define MESH_PATH_TIMEOUT	5000
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/* Minimum interval between two consecutive PREQs originated by the same
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 * interface
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 */
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#define MESH_PREQ_MIN_INT	10
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#define MESH_DIAM_TRAVERSAL_TIME 50
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/* A path will be refreshed if it is used PATH_REFRESH_TIME milliseconds before
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 * timing out.  This way it will remain ACTIVE and no data frames will be
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 * unnecesarily held in the pending queue.
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 */
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#define MESH_PATH_REFRESH_TIME			1000
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#define MESH_MIN_DISCOVERY_TIMEOUT (2 * MESH_DIAM_TRAVERSAL_TIME)
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#define MESH_DEFAULT_BEACON_INTERVAL		1000 	/* in 1024 us units */
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#define MESH_MAX_PREQ_RETRIES 4
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#define MESH_PATH_EXPIRE (600 * HZ)
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/* Default maximum number of established plinks per interface */
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#define MESH_MAX_ESTAB_PLINKS	32
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/* Default maximum number of plinks per interface */
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#define MESH_MAX_PLINKS		256
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/* Maximum number of paths per interface */
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#define MESH_MAX_MPATHS		1024
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/* Pending ANA approval */
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#define MESH_PLINK_CATEGORY	30
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#define MESH_PATH_SEL_CATEGORY	32
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#define MESH_PATH_SEL_ACTION	0
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/* PERR reason codes */
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#define PEER_RCODE_UNSPECIFIED  11
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#define PERR_RCODE_NO_ROUTE     12
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#define PERR_RCODE_DEST_UNREACH 13
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/* Public interfaces */
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/* Various */
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int ieee80211_fill_mesh_addresses(struct ieee80211_hdr *hdr, __le16 *fc,
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				  const u8 *da, const u8 *sa);
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int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
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		struct ieee80211_sub_if_data *sdata, char *addr4,
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		char *addr5, char *addr6);
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int mesh_rmc_check(u8 *addr, struct ieee80211s_hdr *mesh_hdr,
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		struct ieee80211_sub_if_data *sdata);
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bool mesh_matches_local(struct ieee802_11_elems *ie,
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		struct ieee80211_sub_if_data *sdata);
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void mesh_ids_set_default(struct ieee80211_if_mesh *mesh);
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void mesh_mgmt_ies_add(struct sk_buff *skb,
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		struct ieee80211_sub_if_data *sdata);
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void mesh_rmc_free(struct ieee80211_sub_if_data *sdata);
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int mesh_rmc_init(struct ieee80211_sub_if_data *sdata);
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void ieee80211s_init(void);
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void ieee80211s_update_metric(struct ieee80211_local *local,
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		struct sta_info *stainfo, struct sk_buff *skb);
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void ieee80211s_stop(void);
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void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata);
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ieee80211_rx_result
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ieee80211_mesh_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb);
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void ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata);
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void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata);
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void ieee80211_mesh_root_setup(struct ieee80211_if_mesh *ifmsh);
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/* Mesh paths */
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int mesh_nexthop_lookup(struct sk_buff *skb,
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		struct ieee80211_sub_if_data *sdata);
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void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata);
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struct mesh_path *mesh_path_lookup(u8 *dst,
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		struct ieee80211_sub_if_data *sdata);
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struct mesh_path *mpp_path_lookup(u8 *dst,
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				  struct ieee80211_sub_if_data *sdata);
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int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata);
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struct mesh_path *mesh_path_lookup_by_idx(int idx,
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		struct ieee80211_sub_if_data *sdata);
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void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop);
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void mesh_path_expire(struct ieee80211_sub_if_data *sdata);
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void mesh_path_flush(struct ieee80211_sub_if_data *sdata);
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void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
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		struct ieee80211_mgmt *mgmt, size_t len);
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int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata);
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/* Mesh plinks */
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void mesh_neighbour_update(u8 *hw_addr, u32 rates,
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		struct ieee80211_sub_if_data *sdata, bool add);
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bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie);
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void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata);
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void mesh_plink_broken(struct sta_info *sta);
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void mesh_plink_deactivate(struct sta_info *sta);
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int mesh_plink_open(struct sta_info *sta);
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void mesh_plink_block(struct sta_info *sta);
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void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
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			 struct ieee80211_mgmt *mgmt, size_t len,
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			 struct ieee80211_rx_status *rx_status);
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/* Private interfaces */
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/* Mesh tables */
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struct mesh_table *mesh_table_alloc(int size_order);
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void mesh_table_free(struct mesh_table *tbl, bool free_leafs);
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void mesh_mpath_table_grow(void);
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void mesh_mpp_table_grow(void);
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u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
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		struct mesh_table *tbl);
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/* Mesh paths */
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int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn, __le16 target_rcode,
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		       const u8 *ra, struct ieee80211_sub_if_data *sdata);
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void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
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void mesh_path_flush_pending(struct mesh_path *mpath);
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void mesh_path_tx_pending(struct mesh_path *mpath);
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int mesh_pathtbl_init(void);
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void mesh_pathtbl_unregister(void);
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int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata);
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void mesh_path_timer(unsigned long data);
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void mesh_path_flush_by_nexthop(struct sta_info *sta);
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void mesh_path_discard_frame(struct sk_buff *skb,
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		struct ieee80211_sub_if_data *sdata);
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void mesh_path_quiesce(struct ieee80211_sub_if_data *sdata);
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void mesh_path_restart(struct ieee80211_sub_if_data *sdata);
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void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata);
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extern int mesh_paths_generation;
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#ifdef CONFIG_MAC80211_MESH
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extern int mesh_allocated;
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static inline int mesh_plink_free_count(struct ieee80211_sub_if_data *sdata)
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{
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	return sdata->u.mesh.mshcfg.dot11MeshMaxPeerLinks -
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	       atomic_read(&sdata->u.mesh.mshstats.estab_plinks);
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}
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static inline bool mesh_plink_availables(struct ieee80211_sub_if_data *sdata)
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{
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	return (min_t(long, mesh_plink_free_count(sdata),
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		   MESH_MAX_PLINKS - sdata->local->num_sta)) > 0;
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}
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static inline void mesh_path_activate(struct mesh_path *mpath)
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{
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	mpath->flags |= MESH_PATH_ACTIVE | MESH_PATH_RESOLVED;
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}
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#define for_each_mesh_entry(x, p, node, i) \
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	for (i = 0; i <= x->hash_mask; i++) \
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		hlist_for_each_entry_rcu(node, p, &x->hash_buckets[i], list)
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void ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local);
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void ieee80211_mesh_quiesce(struct ieee80211_sub_if_data *sdata);
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void ieee80211_mesh_restart(struct ieee80211_sub_if_data *sdata);
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void mesh_plink_quiesce(struct sta_info *sta);
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void mesh_plink_restart(struct sta_info *sta);
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#else
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#define mesh_allocated	0
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static inline void
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ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local) {}
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static inline void ieee80211_mesh_quiesce(struct ieee80211_sub_if_data *sdata)
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{}
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static inline void ieee80211_mesh_restart(struct ieee80211_sub_if_data *sdata)
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{}
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static inline void mesh_plink_quiesce(struct sta_info *sta) {}
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static inline void mesh_plink_restart(struct sta_info *sta) {}
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#endif
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#endif /* IEEE80211S_H */
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