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linux/net/wireless/ibss.c
Johannes Berg f7969969f4 cfg80211: make spurious warnings less likely, configurable 
Bob reported that he got warnings in IBSS mode about
the ssid_len being zero on a joined event, but only
when kmemcheck was enabled. This appears to be due
to a race condition between drivers and userspace,
when the driver reports joined but the user in the
meantime decided to leave the IBSS again, the warning
would trigger. This was made more likely by kmemcheck
delaying the code that does the check and sends the
event.

So first, make the warning trigger closer to the
driver, which means it's not locked, but since only
the warning depends on it that's ok.

And secondly, users will not want to have spurious
warnings at all, so make those that are known to be
racy in such a way configurable.

Reported-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-28 14:40:30 -04:00

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/*
* Some IBSS support code for cfg80211.
*
* Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
*/
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <net/cfg80211.h>
#include "wext-compat.h"
#include "nl80211.h"
void __cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_bss *bss;
#ifdef CONFIG_WIRELESS_EXT
union iwreq_data wrqu;
#endif
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return;
if (!wdev->ssid_len)
return;
bss = cfg80211_get_bss(wdev->wiphy, NULL, bssid,
wdev->ssid, wdev->ssid_len,
WLAN_CAPABILITY_IBSS, WLAN_CAPABILITY_IBSS);
if (WARN_ON(!bss))
return;
if (wdev->current_bss) {
cfg80211_unhold_bss(wdev->current_bss);
cfg80211_put_bss(&wdev->current_bss->pub);
}
cfg80211_hold_bss(bss_from_pub(bss));
wdev->current_bss = bss_from_pub(bss);
cfg80211_upload_connect_keys(wdev);
nl80211_send_ibss_bssid(wiphy_to_dev(wdev->wiphy), dev, bssid,
GFP_KERNEL);
#ifdef CONFIG_WIRELESS_EXT
memset(&wrqu, 0, sizeof(wrqu));
memcpy(wrqu.ap_addr.sa_data, bssid, ETH_ALEN);
wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
#endif
}
void cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid, gfp_t gfp)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
struct cfg80211_event *ev;
unsigned long flags;
CFG80211_DEV_WARN_ON(!wdev->ssid_len);
ev = kzalloc(sizeof(*ev), gfp);
if (!ev)
return;
ev->type = EVENT_IBSS_JOINED;
memcpy(ev->cr.bssid, bssid, ETH_ALEN);
spin_lock_irqsave(&wdev->event_lock, flags);
list_add_tail(&ev->list, &wdev->event_list);
spin_unlock_irqrestore(&wdev->event_lock, flags);
schedule_work(&rdev->event_work);
}
EXPORT_SYMBOL(cfg80211_ibss_joined);
int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev,
struct cfg80211_ibss_params *params,
struct cfg80211_cached_keys *connkeys)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct ieee80211_channel *chan;
int err;
ASSERT_WDEV_LOCK(wdev);
chan = rdev_fixed_channel(rdev, wdev);
if (chan && chan != params->channel)
return -EBUSY;
if (wdev->ssid_len)
return -EALREADY;
if (WARN_ON(wdev->connect_keys))
kfree(wdev->connect_keys);
wdev->connect_keys = connkeys;
#ifdef CONFIG_WIRELESS_EXT
wdev->wext.ibss.channel = params->channel;
#endif
err = rdev->ops->join_ibss(&rdev->wiphy, dev, params);
if (err) {
wdev->connect_keys = NULL;
return err;
}
memcpy(wdev->ssid, params->ssid, params->ssid_len);
wdev->ssid_len = params->ssid_len;
return 0;
}
int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev,
struct cfg80211_ibss_params *params,
struct cfg80211_cached_keys *connkeys)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = __cfg80211_join_ibss(rdev, dev, params, connkeys);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
static void __cfg80211_clear_ibss(struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
int i;
ASSERT_WDEV_LOCK(wdev);
kfree(wdev->connect_keys);
wdev->connect_keys = NULL;
/*
* Delete all the keys ... pairwise keys can't really
* exist any more anyway, but default keys might.
*/
if (rdev->ops->del_key)
for (i = 0; i < 6; i++)
rdev->ops->del_key(wdev->wiphy, dev, i, NULL);
if (wdev->current_bss) {
cfg80211_unhold_bss(wdev->current_bss);
cfg80211_put_bss(&wdev->current_bss->pub);
}
wdev->current_bss = NULL;
wdev->ssid_len = 0;
#ifdef CONFIG_WIRELESS_EXT
if (!nowext)
wdev->wext.ibss.ssid_len = 0;
#endif
}
void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
wdev_lock(wdev);
__cfg80211_clear_ibss(dev, nowext);
wdev_unlock(wdev);
}
static int __cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
ASSERT_WDEV_LOCK(wdev);
if (!wdev->ssid_len)
return -ENOLINK;
err = rdev->ops->leave_ibss(&rdev->wiphy, dev);
if (err)
return err;
__cfg80211_clear_ibss(dev, nowext);
return 0;
}
int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
wdev_lock(wdev);
err = __cfg80211_leave_ibss(rdev, dev, nowext);
wdev_unlock(wdev);
return err;
}
#ifdef CONFIG_WIRELESS_EXT
int cfg80211_ibss_wext_join(struct cfg80211_registered_device *rdev,
struct wireless_dev *wdev)
{
struct cfg80211_cached_keys *ck = NULL;
enum ieee80211_band band;
int i, err;
ASSERT_WDEV_LOCK(wdev);
if (!wdev->wext.ibss.beacon_interval)
wdev->wext.ibss.beacon_interval = 100;
/* try to find an IBSS channel if none requested ... */
if (!wdev->wext.ibss.channel) {
for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
struct ieee80211_supported_band *sband;
struct ieee80211_channel *chan;
sband = rdev->wiphy.bands[band];
if (!sband)
continue;
for (i = 0; i < sband->n_channels; i++) {
chan = &sband->channels[i];
if (chan->flags & IEEE80211_CHAN_NO_IBSS)
continue;
if (chan->flags & IEEE80211_CHAN_DISABLED)
continue;
wdev->wext.ibss.channel = chan;
break;
}
if (wdev->wext.ibss.channel)
break;
}
if (!wdev->wext.ibss.channel)
return -EINVAL;
}
/* don't join -- SSID is not there */
if (!wdev->wext.ibss.ssid_len)
return 0;
if (!netif_running(wdev->netdev))
return 0;
if (wdev->wext.keys)
wdev->wext.keys->def = wdev->wext.default_key;
wdev->wext.ibss.privacy = wdev->wext.default_key != -1;
if (wdev->wext.keys) {
ck = kmemdup(wdev->wext.keys, sizeof(*ck), GFP_KERNEL);
if (!ck)
return -ENOMEM;
for (i = 0; i < 6; i++)
ck->params[i].key = ck->data[i];
}
err = __cfg80211_join_ibss(rdev, wdev->netdev,
&wdev->wext.ibss, ck);
if (err)
kfree(ck);
return err;
}
int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
struct iw_request_info *info,
struct iw_freq *wextfreq, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
struct ieee80211_channel *chan = NULL;
int err, freq;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
freq = cfg80211_wext_freq(wdev->wiphy, wextfreq);
if (freq < 0)
return freq;
if (freq) {
chan = ieee80211_get_channel(wdev->wiphy, freq);
if (!chan)
return -EINVAL;
if (chan->flags & IEEE80211_CHAN_NO_IBSS ||
chan->flags & IEEE80211_CHAN_DISABLED)
return -EINVAL;
}
if (wdev->wext.ibss.channel == chan)
return 0;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
if (chan) {
wdev->wext.ibss.channel = chan;
wdev->wext.ibss.channel_fixed = true;
} else {
/* cfg80211_ibss_wext_join will pick one if needed */
wdev->wext.ibss.channel_fixed = false;
}
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwfreq(struct net_device *dev,
struct iw_request_info *info,
struct iw_freq *freq, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct ieee80211_channel *chan = NULL;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
wdev_lock(wdev);
if (wdev->current_bss)
chan = wdev->current_bss->pub.channel;
else if (wdev->wext.ibss.channel)
chan = wdev->wext.ibss.channel;
wdev_unlock(wdev);
if (chan) {
freq->m = chan->center_freq;
freq->e = 6;
return 0;
}
/* no channel if not joining */
return -EINVAL;
}
int cfg80211_ibss_wext_siwessid(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
size_t len = data->length;
int err;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
/* iwconfig uses nul termination in SSID.. */
if (len > 0 && ssid[len - 1] == '\0')
len--;
wdev->wext.ibss.ssid = wdev->ssid;
memcpy(wdev->wext.ibss.ssid, ssid, len);
wdev->wext.ibss.ssid_len = len;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwessid(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
data->flags = 0;
wdev_lock(wdev);
if (wdev->ssid_len) {
data->flags = 1;
data->length = wdev->ssid_len;
memcpy(ssid, wdev->ssid, data->length);
} else if (wdev->wext.ibss.ssid && wdev->wext.ibss.ssid_len) {
data->flags = 1;
data->length = wdev->wext.ibss.ssid_len;
memcpy(ssid, wdev->wext.ibss.ssid, data->length);
}
wdev_unlock(wdev);
return 0;
}
int cfg80211_ibss_wext_siwap(struct net_device *dev,
struct iw_request_info *info,
struct sockaddr *ap_addr, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
u8 *bssid = ap_addr->sa_data;
int err;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
if (ap_addr->sa_family != ARPHRD_ETHER)
return -EINVAL;
/* automatic mode */
if (is_zero_ether_addr(bssid) || is_broadcast_ether_addr(bssid))
bssid = NULL;
/* both automatic */
if (!bssid && !wdev->wext.ibss.bssid)
return 0;
/* fixed already - and no change */
if (wdev->wext.ibss.bssid && bssid &&
compare_ether_addr(bssid, wdev->wext.ibss.bssid) == 0)
return 0;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
if (bssid) {
memcpy(wdev->wext.bssid, bssid, ETH_ALEN);
wdev->wext.ibss.bssid = wdev->wext.bssid;
} else
wdev->wext.ibss.bssid = NULL;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwap(struct net_device *dev,
struct iw_request_info *info,
struct sockaddr *ap_addr, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
ap_addr->sa_family = ARPHRD_ETHER;
wdev_lock(wdev);
if (wdev->current_bss)
memcpy(ap_addr->sa_data, wdev->current_bss->pub.bssid, ETH_ALEN);
else if (wdev->wext.ibss.bssid)
memcpy(ap_addr->sa_data, wdev->wext.ibss.bssid, ETH_ALEN);
else
memset(ap_addr->sa_data, 0, ETH_ALEN);
wdev_unlock(wdev);
return 0;
}
#endif
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