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Commit 665e8aaf authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
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mac80211: Disallow concurrent IBSS/STA mode interfaces 



Disallow having more than one IBSS interface up at any time
because of beacon distribution issues, and for now also disallow
having more than one IBSS/STA interface up at the same time
because we use the master interface's BSS struct which would
be completely corrupted when we have more than one up.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 43ba7e95

net/mac80211/ieee80211.c

+47 −4
Original line number Original line Diff line number Diff line
@@ -183,8 +183,52 @@ static int ieee80211_open(struct net_device *dev) 
	list_for_each_entry(nsdata, &local->interfaces, list) {

	list_for_each_entry(nsdata, &local->interfaces, list) {

		struct net_device *ndev = nsdata->dev;

		struct net_device *ndev = nsdata->dev;





		if (ndev != dev && ndev != local->mdev && netif_running(ndev) &&

		if (ndev != dev && ndev != local->mdev && netif_running(ndev)) {

		    compare_ether_addr(dev->dev_addr, ndev->dev_addr) == 0) {

			/*

			 * Allow only a single IBSS interface to be up at any

			 * time. This is restricted because beacon distribution

			 * cannot work properly if both are in the same IBSS.

			 *

			 * To remove this restriction we'd have to disallow them

			 * from setting the same SSID on different IBSS interfaces

			 * belonging to the same hardware. Then, however, we're

			 * faced with having to adopt two different TSF timers...

			 */

			if (sdata->vif.type == IEEE80211_IF_TYPE_IBSS &&

			    nsdata->vif.type == IEEE80211_IF_TYPE_IBSS)

				return -EBUSY;



			/*

			 * Disallow multiple IBSS/STA mode interfaces.

			 *

			 * This is a technical restriction, it is possible although

			 * most likely not IEEE 802.11 compliant to have multiple

			 * STAs with just a single hardware (the TSF timer will not

			 * be adjusted properly.)

			 *

			 * However, because mac80211 uses the master device's BSS

			 * information for each STA/IBSS interface, doing this will

			 * currently corrupt that BSS information completely, unless,

			 * a not very useful case, both STAs are associated to the

			 * same BSS.

			 *

			 * To remove this restriction, the BSS information needs to

			 * be embedded in the STA/IBSS mode sdata instead of using

			 * the master device's BSS structure.

			 */

			if ((sdata->vif.type == IEEE80211_IF_TYPE_STA ||

			     sdata->vif.type == IEEE80211_IF_TYPE_IBSS) &&

			    (nsdata->vif.type == IEEE80211_IF_TYPE_STA ||

			     nsdata->vif.type == IEEE80211_IF_TYPE_IBSS))

				return -EBUSY;



			/*

			 * The remaining checks are only performed for interfaces

			 * with the same MAC address.

			 */

			if (compare_ether_addr(dev->dev_addr, ndev->dev_addr))

				continue;



			/*

			/*

			 * check whether it may have the same address

			 * check whether it may have the same address

			 */

			 */
@@ -196,8 +240,7 @@ static int ieee80211_open(struct net_device *dev) 
			 * can only add VLANs to enabled APs

			 * can only add VLANs to enabled APs

			 */

			 */

			if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN &&

			if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN &&

			    nsdata->vif.type == IEEE80211_IF_TYPE_AP &&

			    nsdata->vif.type == IEEE80211_IF_TYPE_AP)

			    netif_running(nsdata->dev))

				sdata->u.vlan.ap = nsdata;

				sdata->u.vlan.ap = nsdata;

		}

		}

	}

	}