mac80211: add beacon configuration via cfg80211
This patch implements the cfg80211 hooks for configuring beaconing
on an access point interface in mac80211. While doing so, it fixes
a number of races that could badly crash the machine when the
beacon is changed while being requested by the driver.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index d02d9ef..5a4c6ed 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -10,6 +10,7 @@
#include <linux/nl80211.h>
#include <linux/rtnetlink.h>
#include <net/net_namespace.h>
+#include <linux/rcupdate.h>
#include <net/cfg80211.h>
#include "ieee80211_i.h"
#include "cfg.h"
@@ -294,6 +295,158 @@
return 0;
}
+/*
+ * This handles both adding a beacon and setting new beacon info
+ */
+static int ieee80211_config_beacon(struct ieee80211_sub_if_data *sdata,
+ struct beacon_parameters *params)
+{
+ struct beacon_data *new, *old;
+ int new_head_len, new_tail_len;
+ int size;
+ int err = -EINVAL;
+
+ old = sdata->u.ap.beacon;
+
+ /* head must not be zero-length */
+ if (params->head && !params->head_len)
+ return -EINVAL;
+
+ /*
+ * This is a kludge. beacon interval should really be part
+ * of the beacon information.
+ */
+ if (params->interval) {
+ sdata->local->hw.conf.beacon_int = params->interval;
+ if (ieee80211_hw_config(sdata->local))
+ return -EINVAL;
+ /*
+ * We updated some parameter so if below bails out
+ * it's not an error.
+ */
+ err = 0;
+ }
+
+ /* Need to have a beacon head if we don't have one yet */
+ if (!params->head && !old)
+ return err;
+
+ /* sorry, no way to start beaconing without dtim period */
+ if (!params->dtim_period && !old)
+ return err;
+
+ /* new or old head? */
+ if (params->head)
+ new_head_len = params->head_len;
+ else
+ new_head_len = old->head_len;
+
+ /* new or old tail? */
+ if (params->tail || !old)
+ /* params->tail_len will be zero for !params->tail */
+ new_tail_len = params->tail_len;
+ else
+ new_tail_len = old->tail_len;
+
+ size = sizeof(*new) + new_head_len + new_tail_len;
+
+ new = kzalloc(size, GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+
+ /* start filling the new info now */
+
+ /* new or old dtim period? */
+ if (params->dtim_period)
+ new->dtim_period = params->dtim_period;
+ else
+ new->dtim_period = old->dtim_period;
+
+ /*
+ * pointers go into the block we allocated,
+ * memory is | beacon_data | head | tail |
+ */
+ new->head = ((u8 *) new) + sizeof(*new);
+ new->tail = new->head + new_head_len;
+ new->head_len = new_head_len;
+ new->tail_len = new_tail_len;
+
+ /* copy in head */
+ if (params->head)
+ memcpy(new->head, params->head, new_head_len);
+ else
+ memcpy(new->head, old->head, new_head_len);
+
+ /* copy in optional tail */
+ if (params->tail)
+ memcpy(new->tail, params->tail, new_tail_len);
+ else
+ if (old)
+ memcpy(new->tail, old->tail, new_tail_len);
+
+ rcu_assign_pointer(sdata->u.ap.beacon, new);
+
+ synchronize_rcu();
+
+ kfree(old);
+
+ return ieee80211_if_config_beacon(sdata->dev);
+}
+
+static int ieee80211_add_beacon(struct wiphy *wiphy, struct net_device *dev,
+ struct beacon_parameters *params)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ struct beacon_data *old;
+
+ if (sdata->vif.type != IEEE80211_IF_TYPE_AP)
+ return -EINVAL;
+
+ old = sdata->u.ap.beacon;
+
+ if (old)
+ return -EALREADY;
+
+ return ieee80211_config_beacon(sdata, params);
+}
+
+static int ieee80211_set_beacon(struct wiphy *wiphy, struct net_device *dev,
+ struct beacon_parameters *params)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ struct beacon_data *old;
+
+ if (sdata->vif.type != IEEE80211_IF_TYPE_AP)
+ return -EINVAL;
+
+ old = sdata->u.ap.beacon;
+
+ if (!old)
+ return -ENOENT;
+
+ return ieee80211_config_beacon(sdata, params);
+}
+
+static int ieee80211_del_beacon(struct wiphy *wiphy, struct net_device *dev)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ struct beacon_data *old;
+
+ if (sdata->vif.type != IEEE80211_IF_TYPE_AP)
+ return -EINVAL;
+
+ old = sdata->u.ap.beacon;
+
+ if (!old)
+ return -ENOENT;
+
+ rcu_assign_pointer(sdata->u.ap.beacon, NULL);
+ synchronize_rcu();
+ kfree(old);
+
+ return ieee80211_if_config_beacon(dev);
+}
+
struct cfg80211_ops mac80211_config_ops = {
.add_virtual_intf = ieee80211_add_iface,
.del_virtual_intf = ieee80211_del_iface,
@@ -302,5 +455,8 @@
.del_key = ieee80211_del_key,
.get_key = ieee80211_get_key,
.set_default_key = ieee80211_config_default_key,
+ .add_beacon = ieee80211_add_beacon,
+ .set_beacon = ieee80211_set_beacon,
+ .del_beacon = ieee80211_del_beacon,
.get_station = ieee80211_get_station,
};