alistair23-linux/net/mac80211/rate.h
Johannes Berg 35c347ac53 mac80211: lock rate control
Both minstrel (reported by Sven Eckelmann) and the iwlwifi rate
control aren't properly taking concurrency into account. It's
likely that the same is true for other rate control algorithms.

In the case of minstrel this manifests itself in crashes when an
update and other data access are run concurrently, for example
when the stations change bandwidth or similar. In iwlwifi, this
can cause firmware crashes.

Since fixing all rate control algorithms will be very difficult,
just provide locking for invocations. This protects the internal
data structures the algorithms maintain.

I've manipulated hostapd to test this, by having it change its
advertised bandwidth roughly ever 150ms. At the same time, I'm
running a flood ping between the client and the AP, which causes
this race of update vs. get_rate/status to easily happen on the
client. With this change, the system survives this test.

Reported-by: Sven Eckelmann <sven@open-mesh.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2015-04-20 13:05:29 +02:00

204 lines
5.4 KiB
C

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005, Devicescape Software, Inc.
* Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
*
* 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 IEEE80211_RATE_H
#define IEEE80211_RATE_H
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "driver-ops.h"
struct rate_control_ref {
struct ieee80211_local *local;
const struct rate_control_ops *ops;
void *priv;
};
void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_tx_rate_control *txrc);
static inline void rate_control_tx_status(struct ieee80211_local *local,
struct ieee80211_supported_band *sband,
struct sta_info *sta,
struct sk_buff *skb)
{
struct rate_control_ref *ref = local->rate_ctrl;
struct ieee80211_sta *ista = &sta->sta;
void *priv_sta = sta->rate_ctrl_priv;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
return;
spin_lock_bh(&sta->rate_ctrl_lock);
if (ref->ops->tx_status)
ref->ops->tx_status(ref->priv, sband, ista, priv_sta, skb);
else
ref->ops->tx_status_noskb(ref->priv, sband, ista, priv_sta, info);
spin_unlock_bh(&sta->rate_ctrl_lock);
}
static inline void
rate_control_tx_status_noskb(struct ieee80211_local *local,
struct ieee80211_supported_band *sband,
struct sta_info *sta,
struct ieee80211_tx_info *info)
{
struct rate_control_ref *ref = local->rate_ctrl;
struct ieee80211_sta *ista = &sta->sta;
void *priv_sta = sta->rate_ctrl_priv;
if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
return;
if (WARN_ON_ONCE(!ref->ops->tx_status_noskb))
return;
spin_lock_bh(&sta->rate_ctrl_lock);
ref->ops->tx_status_noskb(ref->priv, sband, ista, priv_sta, info);
spin_unlock_bh(&sta->rate_ctrl_lock);
}
static inline void rate_control_rate_init(struct sta_info *sta)
{
struct ieee80211_local *local = sta->sdata->local;
struct rate_control_ref *ref = sta->rate_ctrl;
struct ieee80211_sta *ista = &sta->sta;
void *priv_sta = sta->rate_ctrl_priv;
struct ieee80211_supported_band *sband;
struct ieee80211_chanctx_conf *chanctx_conf;
ieee80211_sta_set_rx_nss(sta);
if (!ref)
return;
rcu_read_lock();
chanctx_conf = rcu_dereference(sta->sdata->vif.chanctx_conf);
if (WARN_ON(!chanctx_conf)) {
rcu_read_unlock();
return;
}
sband = local->hw.wiphy->bands[chanctx_conf->def.chan->band];
spin_lock_bh(&sta->rate_ctrl_lock);
ref->ops->rate_init(ref->priv, sband, &chanctx_conf->def, ista,
priv_sta);
spin_unlock_bh(&sta->rate_ctrl_lock);
rcu_read_unlock();
set_sta_flag(sta, WLAN_STA_RATE_CONTROL);
}
static inline void rate_control_rate_update(struct ieee80211_local *local,
struct ieee80211_supported_band *sband,
struct sta_info *sta, u32 changed)
{
struct rate_control_ref *ref = local->rate_ctrl;
struct ieee80211_sta *ista = &sta->sta;
void *priv_sta = sta->rate_ctrl_priv;
struct ieee80211_chanctx_conf *chanctx_conf;
if (ref && ref->ops->rate_update) {
rcu_read_lock();
chanctx_conf = rcu_dereference(sta->sdata->vif.chanctx_conf);
if (WARN_ON(!chanctx_conf)) {
rcu_read_unlock();
return;
}
spin_lock_bh(&sta->rate_ctrl_lock);
ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
ista, priv_sta, changed);
spin_unlock_bh(&sta->rate_ctrl_lock);
rcu_read_unlock();
}
drv_sta_rc_update(local, sta->sdata, &sta->sta, changed);
}
static inline void *rate_control_alloc_sta(struct rate_control_ref *ref,
struct sta_info *sta, gfp_t gfp)
{
spin_lock_init(&sta->rate_ctrl_lock);
return ref->ops->alloc_sta(ref->priv, &sta->sta, gfp);
}
static inline void rate_control_free_sta(struct sta_info *sta)
{
struct rate_control_ref *ref = sta->rate_ctrl;
struct ieee80211_sta *ista = &sta->sta;
void *priv_sta = sta->rate_ctrl_priv;
ref->ops->free_sta(ref->priv, ista, priv_sta);
}
static inline void rate_control_add_sta_debugfs(struct sta_info *sta)
{
#ifdef CONFIG_MAC80211_DEBUGFS
struct rate_control_ref *ref = sta->rate_ctrl;
if (ref && sta->debugfs.dir && ref->ops->add_sta_debugfs)
ref->ops->add_sta_debugfs(ref->priv, sta->rate_ctrl_priv,
sta->debugfs.dir);
#endif
}
static inline void rate_control_remove_sta_debugfs(struct sta_info *sta)
{
#ifdef CONFIG_MAC80211_DEBUGFS
struct rate_control_ref *ref = sta->rate_ctrl;
if (ref && ref->ops->remove_sta_debugfs)
ref->ops->remove_sta_debugfs(ref->priv, sta->rate_ctrl_priv);
#endif
}
/* Get a reference to the rate control algorithm. If `name' is NULL, get the
* first available algorithm. */
int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
const char *name);
void rate_control_deinitialize(struct ieee80211_local *local);
/* Rate control algorithms */
#ifdef CONFIG_MAC80211_RC_MINSTREL
int rc80211_minstrel_init(void);
void rc80211_minstrel_exit(void);
#else
static inline int rc80211_minstrel_init(void)
{
return 0;
}
static inline void rc80211_minstrel_exit(void)
{
}
#endif
#ifdef CONFIG_MAC80211_RC_MINSTREL_HT
int rc80211_minstrel_ht_init(void);
void rc80211_minstrel_ht_exit(void);
#else
static inline int rc80211_minstrel_ht_init(void)
{
return 0;
}
static inline void rc80211_minstrel_ht_exit(void)
{
}
#endif
#endif /* IEEE80211_RATE_H */