iface.c

/*
 * Interface handling
 *
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
 * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "debugfs_netdev.h"
#include "mesh.h"
#include "led.h"
#include "driver-ops.h"
#include "wme.h"
#include "rate.h"

/**
 * DOC: Interface list locking
 *
 * The interface list in each struct ieee80211_local is protected
 * three-fold:
 *
 * (1) modifications may only be done under the RTNL
 * (2) modifications and readers are protected against each other by
 *     the iflist_mtx.
 * (3) modifications are done in an RCU manner so atomic readers
 *     can traverse the list in RCU-safe blocks.
 *
 * As a consequence, reads (traversals) of the list can be protected
 * by either the RTNL, the iflist_mtx or RCU.
 */

bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_chanctx_conf *chanctx_conf;
	int power;

	rcu_read_lock();
	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
	if (!chanctx_conf) {
		rcu_read_unlock();
		return false;
	}

	power = chanctx_conf->def.chan->max_power;
	rcu_read_unlock();

	if (sdata->user_power_level != IEEE80211_UNSET_POWER_LEVEL)
		power = min(power, sdata->user_power_level);

	if (sdata->ap_power_level != IEEE80211_UNSET_POWER_LEVEL)
		power = min(power, sdata->ap_power_level);

	if (power != sdata->vif.bss_conf.txpower) {
		sdata->vif.bss_conf.txpower = power;
		ieee80211_hw_config(sdata->local, 0);
		return true;
	}

	return false;
}

void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata)
{
	if (__ieee80211_recalc_txpower(sdata))
		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_TXPOWER);
}

static u32 __ieee80211_idle_off(struct ieee80211_local *local)
{
	if (!(local->hw.conf.flags & IEEE80211_CONF_IDLE))
		return 0;

	local->hw.conf.flags &= ~IEEE80211_CONF_IDLE;
	return IEEE80211_CONF_CHANGE_IDLE;
}

static u32 __ieee80211_idle_on(struct ieee80211_local *local)
{
	if (local->hw.conf.flags & IEEE80211_CONF_IDLE)
		return 0;

	ieee80211_flush_queues(local, NULL);

	local->hw.conf.flags |= IEEE80211_CONF_IDLE;
	return IEEE80211_CONF_CHANGE_IDLE;
}

static u32 __ieee80211_recalc_idle(struct ieee80211_local *local,
				   bool force_active)
{
	bool working = false, scanning, active;
	unsigned int led_trig_start = 0, led_trig_stop = 0;
	struct ieee80211_roc_work *roc;

	lockdep_assert_held(&local->mtx);

	active = force_active ||
		 !list_empty(&local->chanctx_list) ||
		 local->monitors;

	if (!local->ops->remain_on_channel) {
		list_for_each_entry(roc, &local->roc_list, list) {
			working = true;
			break;
		}
	}

	scanning = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
		   test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);

	if (working || scanning)
		led_trig_start |= IEEE80211_TPT_LEDTRIG_FL_WORK;
	else
		led_trig_stop |= IEEE80211_TPT_LEDTRIG_FL_WORK;

	if (active)
		led_trig_start |= IEEE80211_TPT_LEDTRIG_FL_CONNECTED;
	else
		led_trig_stop |= IEEE80211_TPT_LEDTRIG_FL_CONNECTED;

	ieee80211_mod_tpt_led_trig(local, led_trig_start, led_trig_stop);

	if (working || scanning || active)
		return __ieee80211_idle_off(local);
	return __ieee80211_idle_on(local);
}

u32 ieee80211_idle_off(struct ieee80211_local *local)
{
	return __ieee80211_recalc_idle(local, true);
}

void ieee80211_recalc_idle(struct ieee80211_local *local)
{
	u32 change = __ieee80211_recalc_idle(local, false);
	if (change)
		ieee80211_hw_config(local, change);
}

static int ieee80211_change_mtu(struct net_device *dev, int new_mtu)
{
	if (new_mtu < 256 || new_mtu > IEEE80211_MAX_DATA_LEN)
		return -EINVAL;

	dev->mtu = new_mtu;
	return 0;
}

static int ieee80211_verify_mac(struct ieee80211_sub_if_data *sdata, u8 *addr,
				bool check_dup)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_sub_if_data *iter;
	u64 new, mask, tmp;
	u8 *m;
	int ret = 0;

	if (is_zero_ether_addr(local->hw.wiphy->addr_mask))
		return 0;

	m = addr;
	new =	((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
		((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
		((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

	m = local->hw.wiphy->addr_mask;
	mask =	((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
		((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
		((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

	if (!check_dup)
		return ret;

	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(iter, &local->interfaces, list) {
		if (iter == sdata)
			continue;

		if (iter->vif.type == NL80211_IFTYPE_MONITOR &&
		    !(iter->u.mntr_flags & MONITOR_FLAG_ACTIVE))
			continue;

		m = iter->vif.addr;
		tmp =	((u64)m[0] << 5*8) | ((u64)m[1] << 4*8) |
			((u64)m[2] << 3*8) | ((u64)m[3] << 2*8) |
			((u64)m[4] << 1*8) | ((u64)m[5] << 0*8);

		if ((new & ~mask) != (tmp & ~mask)) {
			ret = -EINVAL;
			break;
		}
	}
	mutex_unlock(&local->iflist_mtx);

	return ret;
}

static int ieee80211_change_mac(struct net_device *dev, void *addr)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct sockaddr *sa = addr;
	bool check_dup = true;
	int ret;

	if (ieee80211_sdata_running(sdata))
		return -EBUSY;

	if (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
	    !(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE))
		check_dup = false;

	ret = ieee80211_verify_mac(sdata, sa->sa_data, check_dup);
	if (ret)
		return ret;

	ret = eth_mac_addr(dev, sa);

	if (ret == 0)
		memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN);

	return ret;
}

static inline int identical_mac_addr_allowed(int type1, int type2)
{
	return type1 == NL80211_IFTYPE_MONITOR ||
		type2 == NL80211_IFTYPE_MONITOR ||
		type1 == NL80211_IFTYPE_P2P_DEVICE ||
		type2 == NL80211_IFTYPE_P2P_DEVICE ||
		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_WDS) ||
		(type1 == NL80211_IFTYPE_WDS &&
			(type2 == NL80211_IFTYPE_WDS ||
			 type2 == NL80211_IFTYPE_AP)) ||
		(type1 == NL80211_IFTYPE_AP && type2 == NL80211_IFTYPE_AP_VLAN) ||
		(type1 == NL80211_IFTYPE_AP_VLAN &&
			(type2 == NL80211_IFTYPE_AP ||
			 type2 == NL80211_IFTYPE_AP_VLAN));
}

static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
					    enum nl80211_iftype iftype)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_sub_if_data *nsdata;

	ASSERT_RTNL();

	/* we hold the RTNL here so can safely walk the list */
	list_for_each_entry(nsdata, &local->interfaces, list) {
		if (nsdata != sdata && ieee80211_sdata_running(nsdata)) {
			/*
			 * 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 (iftype == NL80211_IFTYPE_ADHOC &&
			    nsdata->vif.type == NL80211_IFTYPE_ADHOC)
				return -EBUSY;

			/*
			 * The remaining checks are only performed for interfaces
			 * with the same MAC address.
			 */
			if (!ether_addr_equal(sdata->vif.addr,
					      nsdata->vif.addr))
				continue;

			/*
			 * check whether it may have the same address
			 */
			if (!identical_mac_addr_allowed(iftype,
							nsdata->vif.type))
				return -ENOTUNIQ;

			/*
			 * can only add VLANs to enabled APs
			 */
			if (iftype == NL80211_IFTYPE_AP_VLAN &&
			    nsdata->vif.type == NL80211_IFTYPE_AP)
				sdata->bss = &nsdata->u.ap;
		}
	}

	return 0;
}

static int ieee80211_check_queues(struct ieee80211_sub_if_data *sdata)
{
	int n_queues = sdata->local->hw.queues;
	int i;

	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE) {
		for (i = 0; i < IEEE80211_NUM_ACS; i++) {
			if (WARN_ON_ONCE(sdata->vif.hw_queue[i] ==
					 IEEE80211_INVAL_HW_QUEUE))
				return -EINVAL;
			if (WARN_ON_ONCE(sdata->vif.hw_queue[i] >=
					 n_queues))
				return -EINVAL;
		}
	}

	if ((sdata->vif.type != NL80211_IFTYPE_AP &&
	     sdata->vif.type != NL80211_IFTYPE_MESH_POINT) ||
	    !(sdata->local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)) {
		sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
		return 0;
	}

	if (WARN_ON_ONCE(sdata->vif.cab_queue == IEEE80211_INVAL_HW_QUEUE))
		return -EINVAL;

	if (WARN_ON_ONCE(sdata->vif.cab_queue >= n_queues))
		return -EINVAL;

	return 0;
}

void ieee80211_adjust_monitor_flags(struct ieee80211_sub_if_data *sdata,
				    const int offset)
{
	struct ieee80211_local *local = sdata->local;
	u32 flags = sdata->u.mntr_flags;

#define ADJUST(_f, _s)	do {					\
	if (flags & MONITOR_FLAG_##_f)				\
		local->fif_##_s += offset;			\
	} while (0)

	ADJUST(FCSFAIL, fcsfail);
	ADJUST(PLCPFAIL, plcpfail);
	ADJUST(CONTROL, control);
	ADJUST(CONTROL, pspoll);
	ADJUST(OTHER_BSS, other_bss);

#undef ADJUST
}

static void ieee80211_set_default_queues(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	int i;

	for (i = 0; i < IEEE80211_NUM_ACS; i++) {
		if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
			sdata->vif.hw_queue[i] = IEEE80211_INVAL_HW_QUEUE;
		else if (local->hw.queues >= IEEE80211_NUM_ACS)
			sdata->vif.hw_queue[i] = i;
		else
			sdata->vif.hw_queue[i] = 0;
	}
	sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
}

int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
{
	struct ieee80211_sub_if_data *sdata;
	int ret;

	if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
		return 0;

	ASSERT_RTNL();

	if (local->monitor_sdata)
		return 0;

	sdata = kzalloc(sizeof(*sdata) + local->hw.vif_data_size, GFP_KERNEL);
	if (!sdata)
		return -ENOMEM;

	/* set up data */
	sdata->local = local;
	sdata->vif.type = NL80211_IFTYPE_MONITOR;
	snprintf(sdata->name, IFNAMSIZ, "%s-monitor",
		 wiphy_name(local->hw.wiphy));

	ieee80211_set_default_queues(sdata);

	ret = drv_add_interface(local, sdata);
	if (WARN_ON(ret)) {
		/* ok .. stupid driver, it asked for this! */
		kfree(sdata);
		return ret;
	}

	ret = ieee80211_check_queues(sdata);
	if (ret) {
		kfree(sdata);
		return ret;
	}

	ret = ieee80211_vif_use_channel(sdata, &local->monitor_chandef,
					IEEE80211_CHANCTX_EXCLUSIVE);
	if (ret) {
		drv_remove_interface(local, sdata);
		kfree(sdata);
		return ret;
	}

	mutex_lock(&local->iflist_mtx);
	rcu_assign_pointer(local->monitor_sdata, sdata);
	mutex_unlock(&local->iflist_mtx);

	return 0;
}

void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
{
	struct ieee80211_sub_if_data *sdata;

	if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
		return;

	ASSERT_RTNL();

	mutex_lock(&local->iflist_mtx);

	sdata = rcu_dereference_protected(local->monitor_sdata,
					  lockdep_is_held(&local->iflist_mtx));
	if (!sdata) {
		mutex_unlock(&local->iflist_mtx);
		return;
	}

	rcu_assign_pointer(local->monitor_sdata, NULL);
	mutex_unlock(&local->iflist_mtx);

	synchronize_net();

	ieee80211_vif_release_channel(sdata);

	drv_remove_interface(local, sdata);

	kfree(sdata);
}

/*
 * NOTE: Be very careful when changing this function, it must NOT return
 * an error on interface type changes that have been pre-checked, so most
 * checks should be in ieee80211_check_concurrent_iface.
 */
int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
	struct net_device *dev = wdev->netdev;
	struct ieee80211_local *local = sdata->local;
	struct sta_info *sta;
	u32 changed = 0;
	int res;
	u32 hw_reconf_flags = 0;

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_WDS:
		if (!is_valid_ether_addr(sdata->u.wds.remote_addr))
			return -ENOLINK;
		break;
	case NL80211_IFTYPE_AP_VLAN: {
		struct ieee80211_sub_if_data *master;

		if (!sdata->bss)
			return -ENOLINK;

		list_add(&sdata->u.vlan.list, &sdata->bss->vlans);

		master = container_of(sdata->bss,
				      struct ieee80211_sub_if_data, u.ap);
		sdata->control_port_protocol =
			master->control_port_protocol;
		sdata->control_port_no_encrypt =
			master->control_port_no_encrypt;
		sdata->vif.cab_queue = master->vif.cab_queue;
		memcpy(sdata->vif.hw_queue, master->vif.hw_queue,
		       sizeof(sdata->vif.hw_queue));
		break;
		}
	case NL80211_IFTYPE_AP:
		sdata->bss = &sdata->u.ap;
		break;
	case NL80211_IFTYPE_MESH_POINT:
	case NL80211_IFTYPE_STATION:
	case NL80211_IFTYPE_MONITOR:
	case NL80211_IFTYPE_ADHOC:
	case NL80211_IFTYPE_P2P_DEVICE:
		/* no special treatment */
		break;
	case NL80211_IFTYPE_UNSPECIFIED:
	case NUM_NL80211_IFTYPES:
	case NL80211_IFTYPE_P2P_CLIENT:
	case NL80211_IFTYPE_P2P_GO:
		/* cannot happen */
		WARN_ON(1);
		break;
	}

	if (local->open_count == 0) {
		res = drv_start(local);
		if (res)
			goto err_del_bss;
		/* we're brought up, everything changes */
		hw_reconf_flags = ~0;
		ieee80211_led_radio(local, true);
		ieee80211_mod_tpt_led_trig(local,
					   IEEE80211_TPT_LEDTRIG_FL_RADIO, 0);
	}

	/*
	 * Copy the hopefully now-present MAC address to
	 * this interface, if it has the special null one.
	 */
	if (dev && is_zero_ether_addr(dev->dev_addr)) {
		memcpy(dev->dev_addr,
		       local->hw.wiphy->perm_addr,
		       ETH_ALEN);
		memcpy(dev->perm_addr, dev->dev_addr, ETH_ALEN);

		if (!is_valid_ether_addr(dev->dev_addr)) {
			res = -EADDRNOTAVAIL;
			goto err_stop;
		}
	}

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_AP_VLAN:
		/* no need to tell driver, but set carrier and chanctx */
		if (rtnl_dereference(sdata->bss->beacon)) {
			ieee80211_vif_vlan_copy_chanctx(sdata);
			netif_carrier_on(dev);
		} else {
			netif_carrier_off(dev);
		}
		break;
	case NL80211_IFTYPE_MONITOR:
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
			local->cooked_mntrs++;
			break;
		}

		if (sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE) {
			res = drv_add_interface(local, sdata);
			if (res)
				goto err_stop;
		} else if (local->monitors == 0 && local->open_count == 0) {
			res = ieee80211_add_virtual_monitor(local);
			if (res)
				goto err_stop;
		}

		/* must be before the call to ieee80211_configure_filter */
		local->monitors++;
		if (local->monitors == 1) {
			local->hw.conf.flags |= IEEE80211_CONF_MONITOR;
			hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
		}

		ieee80211_adjust_monitor_flags(sdata, 1);
		ieee80211_configure_filter(local);
		mutex_lock(&local->mtx);
		ieee80211_recalc_idle(local);
		mutex_unlock(&local->mtx);

		netif_carrier_on(dev);
		break;
	default:
		if (coming_up) {
			ieee80211_del_virtual_monitor(local);

			res = drv_add_interface(local, sdata);
			if (res)
				goto err_stop;
			res = ieee80211_check_queues(sdata);
			if (res)
				goto err_del_interface;
		}

		if (sdata->vif.type == NL80211_IFTYPE_AP) {
			local->fif_pspoll++;
			local->fif_probe_req++;

			ieee80211_configure_filter(local);
		} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
			local->fif_probe_req++;
		}

		if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE)
			changed |= ieee80211_reset_erp_info(sdata);
		ieee80211_bss_info_change_notify(sdata, changed);

		switch (sdata->vif.type) {
		case NL80211_IFTYPE_STATION:
		case NL80211_IFTYPE_ADHOC:
		case NL80211_IFTYPE_AP:
		case NL80211_IFTYPE_MESH_POINT:
			netif_carrier_off(dev);
			break;
		case NL80211_IFTYPE_WDS:
		case NL80211_IFTYPE_P2P_DEVICE:
			break;
		default:
			/* not reached */
			WARN_ON(1);
		}

		/*
		 * set default queue parameters so drivers don't
		 * need to initialise the hardware if the hardware
		 * doesn't start up with sane defaults
		 */
		ieee80211_set_wmm_default(sdata, true);
	}

	set_bit(SDATA_STATE_RUNNING, &sdata->state);

	if (sdata->vif.type == NL80211_IFTYPE_WDS) {
		/* Create STA entry for the WDS peer */
		sta = sta_info_alloc(sdata, sdata->u.wds.remote_addr,
				     GFP_KERNEL);
		if (!sta) {
			res = -ENOMEM;
			goto err_del_interface;
		}

		sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
		sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
		sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);

		res = sta_info_insert(sta);
		if (res) {
			/* STA has been freed */
			goto err_del_interface;
		}

		rate_control_rate_init(sta);
		netif_carrier_on(dev);
	} else if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE) {
		rcu_assign_pointer(local->p2p_sdata, sdata);
	}

	/*
	 * set_multicast_list will be invoked by the networking core
	 * which will check whether any increments here were done in
	 * error and sync them down to the hardware as filter flags.
	 */
	if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
		atomic_inc(&local->iff_allmultis);

	if (sdata->flags & IEEE80211_SDATA_PROMISC)
		atomic_inc(&local->iff_promiscs);

	if (coming_up)
		local->open_count++;

	if (hw_reconf_flags)
		ieee80211_hw_config(local, hw_reconf_flags);

	ieee80211_recalc_ps(local, -1);

	if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
		/* XXX: for AP_VLAN, actually track AP queues */
		netif_tx_start_all_queues(dev);
	} else if (dev) {
		unsigned long flags;
		int n_acs = IEEE80211_NUM_ACS;
		int ac;

		if (local->hw.queues < IEEE80211_NUM_ACS)
			n_acs = 1;

		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
		if (sdata->vif.cab_queue == IEEE80211_INVAL_HW_QUEUE ||
		    (local->queue_stop_reasons[sdata->vif.cab_queue] == 0 &&
		     skb_queue_empty(&local->pending[sdata->vif.cab_queue]))) {
			for (ac = 0; ac < n_acs; ac++) {
				int ac_queue = sdata->vif.hw_queue[ac];

				if (local->queue_stop_reasons[ac_queue] == 0 &&
				    skb_queue_empty(&local->pending[ac_queue]))
					netif_start_subqueue(dev, ac);
			}
		}
		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
	}

	return 0;
 err_del_interface:
	drv_remove_interface(local, sdata);
 err_stop:
	if (!local->open_count)
		drv_stop(local);
 err_del_bss:
	sdata->bss = NULL;
	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
		list_del(&sdata->u.vlan.list);
	/* might already be clear but that doesn't matter */
	clear_bit(SDATA_STATE_RUNNING, &sdata->state);
	return res;
}

static int ieee80211_open(struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	int err;

	/* fail early if user set an invalid address */
	if (!is_valid_ether_addr(dev->dev_addr))
		return -EADDRNOTAVAIL;

	err = ieee80211_check_concurrent_iface(sdata, sdata->vif.type);
	if (err)
		return err;

	return ieee80211_do_open(&sdata->wdev, true);
}

static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
			      bool going_down)
{
	struct ieee80211_local *local = sdata->local;
	unsigned long flags;
	struct sk_buff *skb, *tmp;
	u32 hw_reconf_flags = 0;
	int i, flushed;
	struct ps_data *ps;

	clear_bit(SDATA_STATE_RUNNING, &sdata->state);

	if (rcu_access_pointer(local->scan_sdata) == sdata)
		ieee80211_scan_cancel(local);

	/*
	 * Stop TX on this interface first.
	 */
	if (sdata->dev)
		netif_tx_stop_all_queues(sdata->dev);

	ieee80211_roc_purge(local, sdata);

	if (sdata->vif.type == NL80211_IFTYPE_STATION)
		ieee80211_mgd_stop(sdata);

	/*
	 * Remove all stations associated with this interface.
	 *
	 * This must be done before calling ops->remove_interface()
	 * because otherwise we can later invoke ops->sta_notify()
	 * whenever the STAs are removed, and that invalidates driver
	 * assumptions about always getting a vif pointer that is valid
	 * (because if we remove a STA after ops->remove_interface()
	 * the driver will have removed the vif info already!)
	 *
	 * This is relevant only in WDS mode, in all other modes we've
	 * already removed all stations when disconnecting or similar,
	 * so warn otherwise.
	 *
	 * We call sta_info_flush_cleanup() later, to combine RCU waits.
	 */
	flushed = sta_info_flush_defer(sdata);
	WARN_ON_ONCE((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) ||
		     (sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1));

	/* don't count this interface for promisc/allmulti while it is down */
	if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
		atomic_dec(&local->iff_allmultis);

	if (sdata->flags & IEEE80211_SDATA_PROMISC)
		atomic_dec(&local->iff_promiscs);

	if (sdata->vif.type == NL80211_IFTYPE_AP) {
		local->fif_pspoll--;
		local->fif_probe_req--;
	} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
		local->fif_probe_req--;
	}

	if (sdata->dev) {
		netif_addr_lock_bh(sdata->dev);
		spin_lock_bh(&local->filter_lock);
		__hw_addr_unsync(&local->mc_list, &sdata->dev->mc,
				 sdata->dev->addr_len);
		spin_unlock_bh(&local->filter_lock);
		netif_addr_unlock_bh(sdata->dev);
	}

	del_timer_sync(&local->dynamic_ps_timer);
	cancel_work_sync(&local->dynamic_ps_enable_work);

	cancel_work_sync(&sdata->recalc_smps);

	cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);

	if (sdata->wdev.cac_started) {
		WARN_ON(local->suspended);
		mutex_lock(&local->iflist_mtx);
		ieee80211_vif_release_channel(sdata);
		mutex_unlock(&local->iflist_mtx);
		cfg80211_cac_event(sdata->dev, NL80211_RADAR_CAC_ABORTED,
				   GFP_KERNEL);
	}

	/* APs need special treatment */
	if (sdata->vif.type == NL80211_IFTYPE_AP) {
		struct ieee80211_sub_if_data *vlan, *tmpsdata;

		/* down all dependent devices, that is VLANs */
		list_for_each_entry_safe(vlan, tmpsdata, &sdata->u.ap.vlans,
					 u.vlan.list)
			dev_close(vlan->dev);
		WARN_ON(!list_empty(&sdata->u.ap.vlans));
	} else if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
		/* remove all packets in parent bc_buf pointing to this dev */
		ps = &sdata->bss->ps;

		spin_lock_irqsave(&ps->bc_buf.lock, flags);
		skb_queue_walk_safe(&ps->bc_buf, skb, tmp) {
			if (skb->dev == sdata->dev) {
				__skb_unlink(skb, &ps->bc_buf);
				local->total_ps_buffered--;
				ieee80211_free_txskb(&local->hw, skb);
			}
		}
		spin_unlock_irqrestore(&ps->bc_buf.lock, flags);
	}

	if (going_down)
		local->open_count--;

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_AP_VLAN:
		list_del(&sdata->u.vlan.list);
		rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
		/* no need to tell driver */
		break;
	case NL80211_IFTYPE_MONITOR:
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
			local->cooked_mntrs--;
			break;
		}

		local->monitors--;
		if (local->monitors == 0) {
			local->hw.conf.flags &= ~IEEE80211_CONF_MONITOR;
			hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
		}

		ieee80211_adjust_monitor_flags(sdata, -1);
		break;
	case NL80211_IFTYPE_P2P_DEVICE:
		/* relies on synchronize_rcu() below */
		rcu_assign_pointer(local->p2p_sdata, NULL);
		/* fall through */
	default:
		cancel_work_sync(&sdata->work);
		/*
		 * When we get here, the interface is marked down.
		 *
		 * sta_info_flush_cleanup() requires rcu_barrier()
		 * first to wait for the station call_rcu() calls
		 * to complete, and we also need synchronize_rcu()
		 * to wait for the RX path in case it is using the
		 * interface and enqueuing frames at this very time on
		 * another CPU.
		 */
		synchronize_rcu();
		rcu_barrier();
		sta_info_flush_cleanup(sdata);

		/*
		 * Free all remaining keys, there shouldn't be any,
		 * except maybe in WDS mode?
		 */
		ieee80211_free_keys(sdata);

		/* fall through */
	case NL80211_IFTYPE_AP:
		skb_queue_purge(&sdata->skb_queue);
	}

	sdata->bss = NULL;

	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
	for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
		skb_queue_walk_safe(&local->pending[i], skb, tmp) {
			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
			if (info->control.vif == &sdata->vif) {
				__skb_unlink(skb, &local->pending[i]);
				ieee80211_free_txskb(&local->hw, skb);
			}
		}
	}
	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);

	if (local->open_count == 0)
		ieee80211_clear_tx_pending(local);

	/*
	 * If the interface goes down while suspended, presumably because
	 * the device was unplugged and that happens before our resume,
	 * then the driver is already unconfigured and the remainder of
	 * this function isn't needed.
	 * XXX: what about WoWLAN? If the device has software state, e.g.
	 *	memory allocated, it might expect teardown commands from
	 *	mac80211 here?
	 */
	if (local->suspended) {
		WARN_ON(local->wowlan);
		WARN_ON(rtnl_dereference(local->monitor_sdata));
		return;
	}

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_AP_VLAN:
		break;
	case NL80211_IFTYPE_MONITOR:
		if (local->monitors == 0)
			ieee80211_del_virtual_monitor(local);

		mutex_lock(&local->mtx);
		ieee80211_recalc_idle(local);
		mutex_unlock(&local->mtx);

		if (!(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE))
			break;

		/* fall through */
	default:
		if (going_down)
			drv_remove_interface(local, sdata);
	}

	ieee80211_recalc_ps(local, -1);

	if (local->open_count == 0) {
		ieee80211_stop_device(local);

		/* no reconfiguring after stop! */
		return;
	}

	/* do after stop to avoid reconfiguring when we stop anyway */
	ieee80211_configure_filter(local);
	ieee80211_hw_config(local, hw_reconf_flags);

	if (local->monitors == local->open_count)
		ieee80211_add_virtual_monitor(local);
}

static int ieee80211_stop(struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	ieee80211_do_stop(sdata, true);

	return 0;
}

static void ieee80211_set_multicast_list(struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_local *local = sdata->local;
	int allmulti, promisc, sdata_allmulti, sdata_promisc;

	allmulti = !!(dev->flags & IFF_ALLMULTI);
	promisc = !!(dev->flags & IFF_PROMISC);
	sdata_allmulti = !!(sdata->flags & IEEE80211_SDATA_ALLMULTI);
	sdata_promisc = !!(sdata->flags & IEEE80211_SDATA_PROMISC);

	if (allmulti != sdata_allmulti) {
		if (dev->flags & IFF_ALLMULTI)
			atomic_inc(&local->iff_allmultis);
		else
			atomic_dec(&local->iff_allmultis);
		sdata->flags ^= IEEE80211_SDATA_ALLMULTI;
	}

	if (promisc != sdata_promisc) {
		if (dev->flags & IFF_PROMISC)
			atomic_inc(&local->iff_promiscs);
		else
			atomic_dec(&local->iff_promiscs);
		sdata->flags ^= IEEE80211_SDATA_PROMISC;
	}

	/*
	 * TODO: If somebody needs this on AP interfaces,
	 *	 it can be enabled easily but multicast
	 *	 addresses from VLANs need to be synced.
	 */
	if (sdata->vif.type != NL80211_IFTYPE_MONITOR &&
	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
	    sdata->vif.type != NL80211_IFTYPE_AP)
		drv_set_multicast_list(local, sdata, &dev->mc);

	spin_lock_bh(&local->filter_lock);
	__hw_addr_sync(&local->mc_list, &dev->mc, dev->addr_len);
	spin_unlock_bh(&local->filter_lock);
	ieee80211_queue_work(&local->hw, &local->reconfig_filter);
}

/*
 * Called when the netdev is removed or, by the code below, before
 * the interface type changes.
 */
static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata)
{
	int flushed;
	int i;

	/* free extra data */
	ieee80211_free_keys(sdata);

	ieee80211_debugfs_remove_netdev(sdata);

	for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++)
		__skb_queue_purge(&sdata->fragments[i].skb_list);
	sdata->fragment_next = 0;

	if (ieee80211_vif_is_mesh(&sdata->vif))
		mesh_rmc_free(sdata);

	flushed = sta_info_flush(sdata);
	WARN_ON(flushed);
}