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linux-next/net/mac80211/mesh.h
Johannes Berg 349eb8cf45 mac80211: annotate and fix RCU in mesh code 
This adds proper RCU annotations to the mesh path
table code, and fixes a number of bugs in the code
that I found while checking the sparse warnings I
got as a result of the annotations.

Some things like the changes in mesh_path_add() or
mesh_pathtbl_init() only serve to shut up sparse,
but other changes like the changes surrounding the
for_each_mesh_entry() macro fix real RCU bugs in
the code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-16 14:25:29 -04:00

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/*
* 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 */
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