nl80211: allow configuring IBSS beacon interval

Make the JOIN_IBSS command look at the beacon interval
attribute to see if the user requested a specific beacon
interval, if not default to 100 TU (wext too).
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/nl80211.h

@@ -230,7 +230,9 @@
  *	and optionally a MAC (as BSSID) and FREQ_FIXED attribute if those
  *	should be fixed rather than automatically determined. Can only be
  *	executed on a network interface that is UP, and fixed BSSID/FREQ
- *	may be rejected.
+ *	may be rejected. Another optional parameter is the beacon interval,
+ *	given in the %NL80211_ATTR_BEACON_INTERVAL attribute, which if not
+ *	given defaults to 100 TU (102.4ms).
  * @NL80211_CMD_LEAVE_IBSS: Leave the IBSS -- no special arguments, the IBSS is
  *	determined by the network interface.
  *

include/net/cfg80211.h

@@ -733,6 +733,7 @@ struct cfg80211_disassoc_request {
  *	IBSSs to join on other channels.
  * @ie: information element(s) to include in the beacon
  * @ie_len: length of that
+ * @beacon_interval: beacon interval to use
  */
 struct cfg80211_ibss_params {
 	u8 *ssid;
@@ -740,6 +741,7 @@ struct cfg80211_ibss_params {
 	struct ieee80211_channel *channel;
 	u8 *ie;
 	u8 ssid_len, ie_len;
+	u16 beacon_interval;
 	bool channel_fixed;
 };
 

net/wireless/ibss.c

@@ -116,6 +116,9 @@ static int cfg80211_ibss_wext_join(struct cfg80211_registered_device *rdev,
 	enum ieee80211_band band;
 	int i;
 
+	if (!wdev->wext.beacon_interval)
+		wdev->wext.beacon_interval = 100;
+
 	/* try to find an IBSS channel if none requested ... */
 	if (!wdev->wext.channel) {
 		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

net/wireless/nl80211.c

@@ -3159,6 +3159,8 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 	struct wiphy *wiphy;
 	int err;
 
+	memset(&ibss, 0, sizeof(ibss));
+
 	if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
 		return -EINVAL;
 
@@ -3167,6 +3169,15 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 	    !nla_len(info->attrs[NL80211_ATTR_SSID]))
 		return -EINVAL;
 
+	ibss.beacon_interval = 100;
+
+	if (info->attrs[NL80211_ATTR_BEACON_INTERVAL]) {
+		ibss.beacon_interval =
+			nla_get_u32(info->attrs[NL80211_ATTR_BEACON_INTERVAL]);
+		if (ibss.beacon_interval < 1 || ibss.beacon_interval > 10000)
+			return -EINVAL;
+	}
+
 	rtnl_lock();
 
 	err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev);
@@ -3189,7 +3200,6 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	wiphy = &drv->wiphy;
-	memset(&ibss, 0, sizeof(ibss));
 
 	if (info->attrs[NL80211_ATTR_MAC])
 		ibss.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);