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Commit 5dfdaf58 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

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: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 51fb61e7

net/mac80211/cfg.c

+156 −0
Original line number Diff line number Diff line
@@ -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 @@ static int ieee80211_get_station(struct wiphy *wiphy, struct net_device *dev, 
	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 @@ struct cfg80211_ops mac80211_config_ops = { 
	.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,

};

net/mac80211/debugfs_netdev.c

+0 −27
Original line number Diff line number Diff line
@@ -124,7 +124,6 @@ __IEEE80211_IF_FILE(flags); 


/* AP attributes */

IEEE80211_IF_FILE(num_sta_ps, u.ap.num_sta_ps, ATOMIC);

IEEE80211_IF_FILE(dtim_period, u.ap.dtim_period, DEC);

IEEE80211_IF_FILE(dtim_count, u.ap.dtim_count, DEC);

IEEE80211_IF_FILE(num_beacons, u.ap.num_beacons, DEC);

IEEE80211_IF_FILE(force_unicast_rateidx, u.ap.force_unicast_rateidx, DEC);
@@ -138,26 +137,6 @@ static ssize_t ieee80211_if_fmt_num_buffered_multicast( 
}

__IEEE80211_IF_FILE(num_buffered_multicast);



static ssize_t ieee80211_if_fmt_beacon_head_len(

	const struct ieee80211_sub_if_data *sdata, char *buf, int buflen)

{

	if (sdata->u.ap.beacon_head)

		return scnprintf(buf, buflen, "%d\n",

				 sdata->u.ap.beacon_head_len);

	return scnprintf(buf, buflen, "\n");

}

__IEEE80211_IF_FILE(beacon_head_len);



static ssize_t ieee80211_if_fmt_beacon_tail_len(

	const struct ieee80211_sub_if_data *sdata, char *buf, int buflen)

{

	if (sdata->u.ap.beacon_tail)

		return scnprintf(buf, buflen, "%d\n",

				 sdata->u.ap.beacon_tail_len);

	return scnprintf(buf, buflen, "\n");

}

__IEEE80211_IF_FILE(beacon_tail_len);



/* WDS attributes */

IEEE80211_IF_FILE(peer, u.wds.remote_addr, MAC);
@@ -192,14 +171,11 @@ static void add_ap_files(struct ieee80211_sub_if_data *sdata) 
	DEBUGFS_ADD(drop_unencrypted, ap);

	DEBUGFS_ADD(ieee802_1x_pac, ap);

	DEBUGFS_ADD(num_sta_ps, ap);

	DEBUGFS_ADD(dtim_period, ap);

	DEBUGFS_ADD(dtim_count, ap);

	DEBUGFS_ADD(num_beacons, ap);

	DEBUGFS_ADD(force_unicast_rateidx, ap);

	DEBUGFS_ADD(max_ratectrl_rateidx, ap);

	DEBUGFS_ADD(num_buffered_multicast, ap);

	DEBUGFS_ADD(beacon_head_len, ap);

	DEBUGFS_ADD(beacon_tail_len, ap);

}



static void add_wds_files(struct ieee80211_sub_if_data *sdata)
@@ -281,14 +257,11 @@ static void del_ap_files(struct ieee80211_sub_if_data *sdata) 
	DEBUGFS_DEL(drop_unencrypted, ap);

	DEBUGFS_DEL(ieee802_1x_pac, ap);

	DEBUGFS_DEL(num_sta_ps, ap);

	DEBUGFS_DEL(dtim_period, ap);

	DEBUGFS_DEL(dtim_count, ap);

	DEBUGFS_DEL(num_beacons, ap);

	DEBUGFS_DEL(force_unicast_rateidx, ap);

	DEBUGFS_DEL(max_ratectrl_rateidx, ap);

	DEBUGFS_DEL(num_buffered_multicast, ap);

	DEBUGFS_DEL(beacon_head_len, ap);

	DEBUGFS_DEL(beacon_tail_len, ap);

}



static void del_wds_files(struct ieee80211_sub_if_data *sdata)

net/mac80211/ieee80211.c

+8 −1
Original line number Diff line number Diff line
@@ -321,10 +321,17 @@ static int ieee80211_stop(struct net_device *dev) 


	dev_mc_unsync(local->mdev, dev);



	/* down all dependent devices, that is VLANs */

	/* APs need special treatment */

	if (sdata->vif.type == IEEE80211_IF_TYPE_AP) {

		struct ieee80211_sub_if_data *vlan, *tmp;

		struct beacon_data *old_beacon = sdata->u.ap.beacon;



		/* remove beacon */

		rcu_assign_pointer(sdata->u.ap.beacon, NULL);

		synchronize_rcu();

		kfree(old_beacon);



		/* down all dependent devices, that is VLANs */

		list_for_each_entry_safe(vlan, tmp, &sdata->u.ap.vlans,

					 u.vlan.list)

			dev_close(vlan->dev);

net/mac80211/ieee80211_i.h

+8 −6
Original line number Diff line number Diff line
@@ -190,9 +190,14 @@ typedef ieee80211_txrx_result (*ieee80211_tx_handler) 
typedef ieee80211_txrx_result (*ieee80211_rx_handler)

(struct ieee80211_txrx_data *rx);



struct beacon_data {

	u8 *head, *tail;

	int head_len, tail_len;

	int dtim_period;

};



struct ieee80211_if_ap {

	u8 *beacon_head, *beacon_tail;

	int beacon_head_len, beacon_tail_len;

	struct beacon_data *beacon;



	struct list_head vlans;
@@ -205,7 +210,7 @@ struct ieee80211_if_ap { 
	u8 tim[sizeof(unsigned long) * BITS_TO_LONGS(IEEE80211_MAX_AID + 1)];

	atomic_t num_sta_ps; /* number of stations in PS mode */

	struct sk_buff_head ps_bc_buf;

	int dtim_period, dtim_count;

	int dtim_count;

	int force_unicast_rateidx; /* forced TX rateidx for unicast frames */

	int max_ratectrl_rateidx; /* max TX rateidx for rate control */

	int num_beacons; /* number of TXed beacon frames for this BSS */
@@ -360,14 +365,11 @@ struct ieee80211_sub_if_data { 
			struct dentry *drop_unencrypted;

			struct dentry *ieee802_1x_pac;

			struct dentry *num_sta_ps;

			struct dentry *dtim_period;

			struct dentry *dtim_count;

			struct dentry *num_beacons;

			struct dentry *force_unicast_rateidx;

			struct dentry *max_ratectrl_rateidx;

			struct dentry *num_buffered_multicast;

			struct dentry *beacon_head_len;

			struct dentry *beacon_tail_len;

		} ap;

		struct {

			struct dentry *channel_use;

net/mac80211/ieee80211_iface.c

+1 −3
Original line number Diff line number Diff line
@@ -126,7 +126,6 @@ void ieee80211_if_set_type(struct net_device *dev, int type) 
		sdata->u.vlan.ap = NULL;

		break;

	case IEEE80211_IF_TYPE_AP:

		sdata->u.ap.dtim_period = 2;

		sdata->u.ap.force_unicast_rateidx = -1;

		sdata->u.ap.max_ratectrl_rateidx = -1;

		skb_queue_head_init(&sdata->u.ap.ps_bc_buf);
@@ -207,8 +206,7 @@ void ieee80211_if_reinit(struct net_device *dev) 
			}

		}



		kfree(sdata->u.ap.beacon_head);

		kfree(sdata->u.ap.beacon_tail);

		kfree(sdata->u.ap.beacon);



		while ((skb = skb_dequeue(&sdata->u.ap.ps_bc_buf))) {

			local->total_ps_buffered--;