mlme.c

/*
 * BSS client mode implementation
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.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.
 */

/* TODO:
 * order BSS list by RSSI(?) ("quality of AP")
 * scan result table filtering (by capability (privacy, IBSS/BSS, WPA/RSN IE,
 *    SSID)
 */
#include <linux/delay.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/wireless.h>
#include <linux/random.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <net/iw_handler.h>
#include <asm/types.h>

#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "led.h"
#include "mesh.h"

#define IEEE80211_AUTH_TIMEOUT (HZ / 5)
#define IEEE80211_AUTH_MAX_TRIES 3
#define IEEE80211_ASSOC_TIMEOUT (HZ / 5)
#define IEEE80211_ASSOC_MAX_TRIES 3
#define IEEE80211_MONITORING_INTERVAL (2 * HZ)
#define IEEE80211_MESH_HOUSEKEEPING_INTERVAL (60 * HZ)
#define IEEE80211_PROBE_INTERVAL (60 * HZ)
#define IEEE80211_RETRY_AUTH_INTERVAL (1 * HZ)
#define IEEE80211_SCAN_INTERVAL (2 * HZ)
#define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
#define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)

#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
#define IEEE80211_SCAN_RESULT_EXPIRE (10 * HZ)
#define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
#define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
#define IEEE80211_MESH_PEER_INACTIVITY_LIMIT (1800 * HZ)

#define IEEE80211_IBSS_MAX_STA_ENTRIES 128


#define ERP_INFO_USE_PROTECTION BIT(1)

/* mgmt header + 1 byte action code */
#define IEEE80211_MIN_ACTION_SIZE (24 + 1)

#define IEEE80211_ADDBA_PARAM_POLICY_MASK 0x0002
#define IEEE80211_ADDBA_PARAM_TID_MASK 0x003C
#define IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK 0xFFA0
#define IEEE80211_DELBA_PARAM_TID_MASK 0xF000
#define IEEE80211_DELBA_PARAM_INITIATOR_MASK 0x0800

/* next values represent the buffer size for A-MPDU frame.
 * According to IEEE802.11n spec size varies from 8K to 64K (in powers of 2) */
#define IEEE80211_MIN_AMPDU_BUF 0x8
#define IEEE80211_MAX_AMPDU_BUF 0x40

static void ieee80211_send_probe_req(struct net_device *dev, u8 *dst,
				     u8 *ssid, size_t ssid_len);
static struct ieee80211_sta_bss *
ieee80211_rx_bss_get(struct net_device *dev, u8 *bssid, int freq,
		     u8 *ssid, u8 ssid_len);
static void ieee80211_rx_bss_put(struct ieee80211_local *local,
				 struct ieee80211_sta_bss *bss);
static int ieee80211_sta_find_ibss(struct net_device *dev,
				   struct ieee80211_if_sta *ifsta);
static int ieee80211_sta_wep_configured(struct net_device *dev);
static int ieee80211_sta_start_scan(struct net_device *dev,
				    u8 *ssid, size_t ssid_len);
static int ieee80211_sta_config_auth(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta);
static void sta_rx_agg_session_timer_expired(unsigned long data);


void ieee802_11_parse_elems(u8 *start, size_t len,
			    struct ieee802_11_elems *elems)
{
	size_t left = len;
	u8 *pos = start;

	memset(elems, 0, sizeof(*elems));

	while (left >= 2) {
		u8 id, elen;

		id = *pos++;
		elen = *pos++;
		left -= 2;

		if (elen > left)
			return;

		switch (id) {
		case WLAN_EID_SSID:
			elems->ssid = pos;
			elems->ssid_len = elen;
			break;
		case WLAN_EID_SUPP_RATES:
			elems->supp_rates = pos;
			elems->supp_rates_len = elen;
			break;
		case WLAN_EID_FH_PARAMS:
			elems->fh_params = pos;
			elems->fh_params_len = elen;
			break;
		case WLAN_EID_DS_PARAMS:
			elems->ds_params = pos;
			elems->ds_params_len = elen;
			break;
		case WLAN_EID_CF_PARAMS:
			elems->cf_params = pos;
			elems->cf_params_len = elen;
			break;
		case WLAN_EID_TIM:
			elems->tim = pos;
			elems->tim_len = elen;
			break;
		case WLAN_EID_IBSS_PARAMS:
			elems->ibss_params = pos;
			elems->ibss_params_len = elen;
			break;
		case WLAN_EID_CHALLENGE:
			elems->challenge = pos;
			elems->challenge_len = elen;
			break;
		case WLAN_EID_WPA:
			if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
			    pos[2] == 0xf2) {
				/* Microsoft OUI (00:50:F2) */
				if (pos[3] == 1) {
					/* OUI Type 1 - WPA IE */
					elems->wpa = pos;
					elems->wpa_len = elen;
				} else if (elen >= 5 && pos[3] == 2) {
					if (pos[4] == 0) {
						elems->wmm_info = pos;
						elems->wmm_info_len = elen;
					} else if (pos[4] == 1) {
						elems->wmm_param = pos;
						elems->wmm_param_len = elen;
					}
				}
			}
			break;
		case WLAN_EID_RSN:
			elems->rsn = pos;
			elems->rsn_len = elen;
			break;
		case WLAN_EID_ERP_INFO:
			elems->erp_info = pos;
			elems->erp_info_len = elen;
			break;
		case WLAN_EID_EXT_SUPP_RATES:
			elems->ext_supp_rates = pos;
			elems->ext_supp_rates_len = elen;
			break;
		case WLAN_EID_HT_CAPABILITY:
			elems->ht_cap_elem = pos;
			elems->ht_cap_elem_len = elen;
			break;
		case WLAN_EID_HT_EXTRA_INFO:
			elems->ht_info_elem = pos;
			elems->ht_info_elem_len = elen;
			break;
		case WLAN_EID_MESH_ID:
			elems->mesh_id = pos;
			elems->mesh_id_len = elen;
			break;
		case WLAN_EID_MESH_CONFIG:
			elems->mesh_config = pos;
			elems->mesh_config_len = elen;
			break;
		case WLAN_EID_PEER_LINK:
			elems->peer_link = pos;
			elems->peer_link_len = elen;
			break;
		case WLAN_EID_PREQ:
			elems->preq = pos;
			elems->preq_len = elen;
			break;
		case WLAN_EID_PREP:
			elems->prep = pos;
			elems->prep_len = elen;
			break;
		case WLAN_EID_PERR:
			elems->perr = pos;
			elems->perr_len = elen;
			break;
		case WLAN_EID_CHANNEL_SWITCH:
			elems->ch_switch_elem = pos;
			elems->ch_switch_elem_len = elen;
			break;
		case WLAN_EID_QUIET:
			if (!elems->quiet_elem) {
				elems->quiet_elem = pos;
				elems->quiet_elem_len = elen;
			}
			elems->num_of_quiet_elem++;
			break;
		case WLAN_EID_COUNTRY:
			elems->country_elem = pos;
			elems->country_elem_len = elen;
			break;
		case WLAN_EID_PWR_CONSTRAINT:
			elems->pwr_constr_elem = pos;
			elems->pwr_constr_elem_len = elen;
			break;
		default:
			break;
		}

		left -= elen;
		pos += elen;
	}
}


static int ecw2cw(int ecw)
{
	return (1 << ecw) - 1;
}


static void ieee80211_sta_def_wmm_params(struct net_device *dev,
					 struct ieee80211_sta_bss *bss,
					 int ibss)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_local *local = sdata->local;
	int i, have_higher_than_11mbit = 0;


	/* cf. IEEE 802.11 9.2.12 */
	for (i = 0; i < bss->supp_rates_len; i++)
		if ((bss->supp_rates[i] & 0x7f) * 5 > 110)
			have_higher_than_11mbit = 1;

	if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ &&
	    have_higher_than_11mbit)
		sdata->flags |= IEEE80211_SDATA_OPERATING_GMODE;
	else
		sdata->flags &= ~IEEE80211_SDATA_OPERATING_GMODE;


	if (local->ops->conf_tx) {
		struct ieee80211_tx_queue_params qparam;

		memset(&qparam, 0, sizeof(qparam));

		qparam.aifs = 2;

		if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ &&
		    !(sdata->flags & IEEE80211_SDATA_OPERATING_GMODE))
			qparam.cw_min = 31;
		else
			qparam.cw_min = 15;

		qparam.cw_max = 1023;
		qparam.txop = 0;

		for (i = 0; i < local_to_hw(local)->queues; i++)
			local->ops->conf_tx(local_to_hw(local), i, &qparam);
	}
}

static void ieee80211_sta_wmm_params(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta,
				     u8 *wmm_param, size_t wmm_param_len)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_tx_queue_params params;
	size_t left;
	int count;
	u8 *pos;

	if (!(ifsta->flags & IEEE80211_STA_WMM_ENABLED))
		return;

	if (!wmm_param)
		return;

	if (wmm_param_len < 8 || wmm_param[5] /* version */ != 1)
		return;
	count = wmm_param[6] & 0x0f;
	if (count == ifsta->wmm_last_param_set)
		return;
	ifsta->wmm_last_param_set = count;

	pos = wmm_param + 8;
	left = wmm_param_len - 8;

	memset(&params, 0, sizeof(params));

	if (!local->ops->conf_tx)
		return;

	local->wmm_acm = 0;
	for (; left >= 4; left -= 4, pos += 4) {
		int aci = (pos[0] >> 5) & 0x03;
		int acm = (pos[0] >> 4) & 0x01;
		int queue;

		switch (aci) {
		case 1:
			queue = 3;
			if (acm)
				local->wmm_acm |= BIT(0) | BIT(3);
			break;
		case 2:
			queue = 1;
			if (acm)
				local->wmm_acm |= BIT(4) | BIT(5);
			break;
		case 3:
			queue = 0;
			if (acm)
				local->wmm_acm |= BIT(6) | BIT(7);
			break;
		case 0:
		default:
			queue = 2;
			if (acm)
				local->wmm_acm |= BIT(1) | BIT(2);
			break;
		}

		params.aifs = pos[0] & 0x0f;
		params.cw_max = ecw2cw((pos[1] & 0xf0) >> 4);
		params.cw_min = ecw2cw(pos[1] & 0x0f);
		params.txop = get_unaligned_le16(pos + 2);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
		printk(KERN_DEBUG "%s: WMM queue=%d aci=%d acm=%d aifs=%d "
		       "cWmin=%d cWmax=%d txop=%d\n",
		       dev->name, queue, aci, acm, params.aifs, params.cw_min,
		       params.cw_max, params.txop);
#endif
		/* TODO: handle ACM (block TX, fallback to next lowest allowed
		 * AC for now) */
		if (local->ops->conf_tx(local_to_hw(local), queue, &params)) {
			printk(KERN_DEBUG "%s: failed to set TX queue "
			       "parameters for queue %d\n", dev->name, queue);
		}
	}
}

static u32 ieee80211_handle_protect_preamb(struct ieee80211_sub_if_data *sdata,
					   bool use_protection,
					   bool use_short_preamble)
{
	struct ieee80211_bss_conf *bss_conf = &sdata->bss_conf;
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	DECLARE_MAC_BUF(mac);
#endif
	u32 changed = 0;

	if (use_protection != bss_conf->use_cts_prot) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: CTS protection %s (BSSID="
			       "%s)\n",
			       sdata->dev->name,
			       use_protection ? "enabled" : "disabled",
			       print_mac(mac, ifsta->bssid));
		}
#endif
		bss_conf->use_cts_prot = use_protection;
		changed |= BSS_CHANGED_ERP_CTS_PROT;
	}

	if (use_short_preamble != bss_conf->use_short_preamble) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: switched to %s barker preamble"
			       " (BSSID=%s)\n",
			       sdata->dev->name,
			       use_short_preamble ? "short" : "long",
			       print_mac(mac, ifsta->bssid));
		}
#endif
		bss_conf->use_short_preamble = use_short_preamble;
		changed |= BSS_CHANGED_ERP_PREAMBLE;
	}

	return changed;
}

static u32 ieee80211_handle_erp_ie(struct ieee80211_sub_if_data *sdata,
				   u8 erp_value)
{
	bool use_protection = (erp_value & WLAN_ERP_USE_PROTECTION) != 0;
	bool use_short_preamble = (erp_value & WLAN_ERP_BARKER_PREAMBLE) == 0;

	return ieee80211_handle_protect_preamb(sdata,
			use_protection, use_short_preamble);
}

static u32 ieee80211_handle_bss_capability(struct ieee80211_sub_if_data *sdata,
					   struct ieee80211_sta_bss *bss)
{
	u32 changed = 0;

	if (bss->has_erp_value)
		changed |= ieee80211_handle_erp_ie(sdata, bss->erp_value);
	else {
		u16 capab = bss->capability;
		changed |= ieee80211_handle_protect_preamb(sdata, false,
				(capab & WLAN_CAPABILITY_SHORT_PREAMBLE) != 0);
	}

	return changed;
}

int ieee80211_ht_cap_ie_to_ht_info(struct ieee80211_ht_cap *ht_cap_ie,
				   struct ieee80211_ht_info *ht_info)
{

	if (ht_info == NULL)
		return -EINVAL;

	memset(ht_info, 0, sizeof(*ht_info));

	if (ht_cap_ie) {
		u8 ampdu_info = ht_cap_ie->ampdu_params_info;

		ht_info->ht_supported = 1;
		ht_info->cap = le16_to_cpu(ht_cap_ie->cap_info);
		ht_info->ampdu_factor =
			ampdu_info & IEEE80211_HT_CAP_AMPDU_FACTOR;
		ht_info->ampdu_density =
			(ampdu_info & IEEE80211_HT_CAP_AMPDU_DENSITY) >> 2;
		memcpy(ht_info->supp_mcs_set, ht_cap_ie->supp_mcs_set, 16);
	} else
		ht_info->ht_supported = 0;

	return 0;
}

int ieee80211_ht_addt_info_ie_to_ht_bss_info(
			struct ieee80211_ht_addt_info *ht_add_info_ie,
			struct ieee80211_ht_bss_info *bss_info)
{
	if (bss_info == NULL)
		return -EINVAL;

	memset(bss_info, 0, sizeof(*bss_info));

	if (ht_add_info_ie) {
		u16 op_mode;
		op_mode = le16_to_cpu(ht_add_info_ie->operation_mode);

		bss_info->primary_channel = ht_add_info_ie->control_chan;
		bss_info->bss_cap = ht_add_info_ie->ht_param;
		bss_info->bss_op_mode = (u8)(op_mode & 0xff);
	}

	return 0;
}

static void ieee80211_sta_send_associnfo(struct net_device *dev,
					 struct ieee80211_if_sta *ifsta)
{
	char *buf;
	size_t len;
	int i;
	union iwreq_data wrqu;

	if (!ifsta->assocreq_ies && !ifsta->assocresp_ies)
		return;

	buf = kmalloc(50 + 2 * (ifsta->assocreq_ies_len +
				ifsta->assocresp_ies_len), GFP_KERNEL);
	if (!buf)
		return;

	len = sprintf(buf, "ASSOCINFO(");
	if (ifsta->assocreq_ies) {
		len += sprintf(buf + len, "ReqIEs=");
		for (i = 0; i < ifsta->assocreq_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocreq_ies[i]);
		}
	}
	if (ifsta->assocresp_ies) {
		if (ifsta->assocreq_ies)
			len += sprintf(buf + len, " ");
		len += sprintf(buf + len, "RespIEs=");
		for (i = 0; i < ifsta->assocresp_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocresp_ies[i]);
		}
	}
	len += sprintf(buf + len, ")");

	if (len > IW_CUSTOM_MAX) {
		len = sprintf(buf, "ASSOCRESPIE=");
		for (i = 0; i < ifsta->assocresp_ies_len; i++) {
			len += sprintf(buf + len, "%02x",
				       ifsta->assocresp_ies[i]);
		}
	}

	memset(&wrqu, 0, sizeof(wrqu));
	wrqu.data.length = len;
	wireless_send_event(dev, IWEVCUSTOM, &wrqu, buf);

	kfree(buf);
}


static void ieee80211_set_associated(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta,
				     bool assoc)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_conf *conf = &local_to_hw(local)->conf;
	union iwreq_data wrqu;
	u32 changed = BSS_CHANGED_ASSOC;

	if (assoc) {
		struct ieee80211_sta_bss *bss;

		ifsta->flags |= IEEE80211_STA_ASSOCIATED;

		if (sdata->vif.type != IEEE80211_IF_TYPE_STA)
			return;

		bss = ieee80211_rx_bss_get(dev, ifsta->bssid,
					   conf->channel->center_freq,
					   ifsta->ssid, ifsta->ssid_len);
		if (bss) {
			/* set timing information */
			sdata->bss_conf.beacon_int = bss->beacon_int;
			sdata->bss_conf.timestamp = bss->timestamp;

			changed |= ieee80211_handle_bss_capability(sdata, bss);

			ieee80211_rx_bss_put(local, bss);
		}

		if (conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE) {
			changed |= BSS_CHANGED_HT;
			sdata->bss_conf.assoc_ht = 1;
			sdata->bss_conf.ht_conf = &conf->ht_conf;
			sdata->bss_conf.ht_bss_conf = &conf->ht_bss_conf;
		}

		ifsta->flags |= IEEE80211_STA_PREV_BSSID_SET;
		memcpy(ifsta->prev_bssid, sdata->u.sta.bssid, ETH_ALEN);
		memcpy(wrqu.ap_addr.sa_data, sdata->u.sta.bssid, ETH_ALEN);
		ieee80211_sta_send_associnfo(dev, ifsta);
	} else {
		netif_carrier_off(dev);
		ieee80211_sta_tear_down_BA_sessions(dev, ifsta->bssid);
		ifsta->flags &= ~IEEE80211_STA_ASSOCIATED;
		changed |= ieee80211_reset_erp_info(dev);

		sdata->bss_conf.assoc_ht = 0;
		sdata->bss_conf.ht_conf = NULL;
		sdata->bss_conf.ht_bss_conf = NULL;

		memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);
	}
	ifsta->last_probe = jiffies;
	ieee80211_led_assoc(local, assoc);

	sdata->bss_conf.assoc = assoc;
	ieee80211_bss_info_change_notify(sdata, changed);

	if (assoc)
		netif_carrier_on(dev);

	wrqu.ap_addr.sa_family = ARPHRD_ETHER;
	wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
}

static void ieee80211_set_disassoc(struct net_device *dev,
				   struct ieee80211_if_sta *ifsta, int deauth)
{
	if (deauth)
		ifsta->auth_tries = 0;
	ifsta->assoc_tries = 0;
	ieee80211_set_associated(dev, ifsta, 0);
}

void ieee80211_sta_tx(struct net_device *dev, struct sk_buff *skb,
		      int encrypt)
{
	struct ieee80211_sub_if_data *sdata;
	struct ieee80211_tx_info *info;

	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	skb->dev = sdata->local->mdev;
	skb_set_mac_header(skb, 0);
	skb_set_network_header(skb, 0);
	skb_set_transport_header(skb, 0);

	info = IEEE80211_SKB_CB(skb);
	memset(info, 0, sizeof(struct ieee80211_tx_info));
	info->control.ifindex = sdata->dev->ifindex;
	if (!encrypt)
		info->flags |= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;

	dev_queue_xmit(skb);
}


static void ieee80211_send_auth(struct net_device *dev,
				struct ieee80211_if_sta *ifsta,
				int transaction, u8 *extra, size_t extra_len,
				int encrypt)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;

	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
			    sizeof(*mgmt) + 6 + extra_len);
	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer for auth "
		       "frame\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24 + 6);
	memset(mgmt, 0, 24 + 6);
	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					   IEEE80211_STYPE_AUTH);
	if (encrypt)
		mgmt->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
	memcpy(mgmt->da, ifsta->bssid, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
	mgmt->u.auth.auth_alg = cpu_to_le16(ifsta->auth_alg);
	mgmt->u.auth.auth_transaction = cpu_to_le16(transaction);
	ifsta->auth_transaction = transaction + 1;
	mgmt->u.auth.status_code = cpu_to_le16(0);
	if (extra)
		memcpy(skb_put(skb, extra_len), extra, extra_len);

	ieee80211_sta_tx(dev, skb, encrypt);
}


static void ieee80211_authenticate(struct net_device *dev,
				   struct ieee80211_if_sta *ifsta)
{
	DECLARE_MAC_BUF(mac);

	ifsta->auth_tries++;
	if (ifsta->auth_tries > IEEE80211_AUTH_MAX_TRIES) {
		printk(KERN_DEBUG "%s: authentication with AP %s"
		       " timed out\n",
		       dev->name, print_mac(mac, ifsta->bssid));
		ifsta->state = IEEE80211_DISABLED;
		return;
	}

	ifsta->state = IEEE80211_AUTHENTICATE;
	printk(KERN_DEBUG "%s: authenticate with AP %s\n",
	       dev->name, print_mac(mac, ifsta->bssid));

	ieee80211_send_auth(dev, ifsta, 1, NULL, 0, 0);

	mod_timer(&ifsta->timer, jiffies + IEEE80211_AUTH_TIMEOUT);
}

static int ieee80211_compatible_rates(struct ieee80211_sta_bss *bss,
				      struct ieee80211_supported_band *sband,
				      u64 *rates)
{
	int i, j, count;
	*rates = 0;
	count = 0;
	for (i = 0; i < bss->supp_rates_len; i++) {
		int rate = (bss->supp_rates[i] & 0x7F) * 5;

		for (j = 0; j < sband->n_bitrates; j++)
			if (sband->bitrates[j].bitrate == rate) {
				*rates |= BIT(j);
				count++;
				break;
			}
	}

	return count;
}

static void ieee80211_send_assoc(struct net_device *dev,
				 struct ieee80211_if_sta *ifsta)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u8 *pos, *ies;
	int i, len, count, rates_len, supp_rates_len;
	u16 capab;
	struct ieee80211_sta_bss *bss;
	int wmm = 0;
	struct ieee80211_supported_band *sband;
	u64 rates = 0;

	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
			    sizeof(*mgmt) + 200 + ifsta->extra_ie_len +
			    ifsta->ssid_len);
	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer for assoc "
		       "frame\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];

	capab = ifsta->capab;

	if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ) {
		if (!(local->hw.flags & IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE))
			capab |= WLAN_CAPABILITY_SHORT_SLOT_TIME;
		if (!(local->hw.flags & IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE))
			capab |= WLAN_CAPABILITY_SHORT_PREAMBLE;
	}

	bss = ieee80211_rx_bss_get(dev, ifsta->bssid,
				   local->hw.conf.channel->center_freq,
				   ifsta->ssid, ifsta->ssid_len);
	if (bss) {
		if (bss->capability & WLAN_CAPABILITY_PRIVACY)
			capab |= WLAN_CAPABILITY_PRIVACY;
		if (bss->wmm_ie)
			wmm = 1;

		/* get all rates supported by the device and the AP as
		 * some APs don't like getting a superset of their rates
		 * in the association request (e.g. D-Link DAP 1353 in
		 * b-only mode) */
		rates_len = ieee80211_compatible_rates(bss, sband, &rates);

		if ((bss->capability & WLAN_CAPABILITY_SPECTRUM_MGMT) &&
		    (local->hw.flags & IEEE80211_HW_SPECTRUM_MGMT))
			capab |= WLAN_CAPABILITY_SPECTRUM_MGMT;

		ieee80211_rx_bss_put(local, bss);
	} else {
		rates = ~0;
		rates_len = sband->n_bitrates;
	}

	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	memcpy(mgmt->da, ifsta->bssid, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);

	if (ifsta->flags & IEEE80211_STA_PREV_BSSID_SET) {
		skb_put(skb, 10);
		mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
						   IEEE80211_STYPE_REASSOC_REQ);
		mgmt->u.reassoc_req.capab_info = cpu_to_le16(capab);
		mgmt->u.reassoc_req.listen_interval = cpu_to_le16(1);
		memcpy(mgmt->u.reassoc_req.current_ap, ifsta->prev_bssid,
		       ETH_ALEN);
	} else {
		skb_put(skb, 4);
		mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
						   IEEE80211_STYPE_ASSOC_REQ);
		mgmt->u.assoc_req.capab_info = cpu_to_le16(capab);
		mgmt->u.assoc_req.listen_interval = cpu_to_le16(1);
	}

	/* SSID */
	ies = pos = skb_put(skb, 2 + ifsta->ssid_len);
	*pos++ = WLAN_EID_SSID;
	*pos++ = ifsta->ssid_len;
	memcpy(pos, ifsta->ssid, ifsta->ssid_len);

	/* add all rates which were marked to be used above */
	supp_rates_len = rates_len;
	if (supp_rates_len > 8)
		supp_rates_len = 8;

	len = sband->n_bitrates;
	pos = skb_put(skb, supp_rates_len + 2);
	*pos++ = WLAN_EID_SUPP_RATES;
	*pos++ = supp_rates_len;

	count = 0;
	for (i = 0; i < sband->n_bitrates; i++) {
		if (BIT(i) & rates) {
			int rate = sband->bitrates[i].bitrate;
			*pos++ = (u8) (rate / 5);
			if (++count == 8)
				break;
		}
	}

	if (count == 8) {
		pos = skb_put(skb, rates_len - count + 2);
		*pos++ = WLAN_EID_EXT_SUPP_RATES;
		*pos++ = rates_len - count;

		for (i++; i < sband->n_bitrates; i++) {
			if (BIT(i) & rates) {
				int rate = sband->bitrates[i].bitrate;
				*pos++ = (u8) (rate / 5);
			}
		}
	}

	if (capab & WLAN_CAPABILITY_SPECTRUM_MGMT) {
		/* 1. power capabilities */
		pos = skb_put(skb, 4);
		*pos++ = WLAN_EID_PWR_CAPABILITY;
		*pos++ = 2;
		*pos++ = 0; /* min tx power */
		*pos++ = local->hw.conf.channel->max_power; /* max tx power */

		/* 2. supported channels */
		/* TODO: get this in reg domain format */
		pos = skb_put(skb, 2 * sband->n_channels + 2);
		*pos++ = WLAN_EID_SUPPORTED_CHANNELS;
		*pos++ = 2 * sband->n_channels;
		for (i = 0; i < sband->n_channels; i++) {
			*pos++ = ieee80211_frequency_to_channel(
					sband->channels[i].center_freq);
			*pos++ = 1; /* one channel in the subband*/
		}
	}

	if (ifsta->extra_ie) {
		pos = skb_put(skb, ifsta->extra_ie_len);
		memcpy(pos, ifsta->extra_ie, ifsta->extra_ie_len);
	}

	if (wmm && (ifsta->flags & IEEE80211_STA_WMM_ENABLED)) {
		pos = skb_put(skb, 9);
		*pos++ = WLAN_EID_VENDOR_SPECIFIC;
		*pos++ = 7; /* len */
		*pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
		*pos++ = 0x50;
		*pos++ = 0xf2;
		*pos++ = 2; /* WME */
		*pos++ = 0; /* WME info */
		*pos++ = 1; /* WME ver */
		*pos++ = 0;
	}

	/* wmm support is a must to HT */
	if (wmm && (ifsta->flags & IEEE80211_STA_WMM_ENABLED) &&
	    sband->ht_info.ht_supported && bss->ht_add_ie) {
		struct ieee80211_ht_addt_info *ht_add_info =
			(struct ieee80211_ht_addt_info *)bss->ht_add_ie;
		u16 cap = sband->ht_info.cap;
		__le16 tmp;
		u32 flags = local->hw.conf.channel->flags;

		switch (ht_add_info->ht_param & IEEE80211_HT_IE_CHA_SEC_OFFSET) {
		case IEEE80211_HT_IE_CHA_SEC_ABOVE:
			if (flags & IEEE80211_CHAN_NO_FAT_ABOVE) {
				cap &= ~IEEE80211_HT_CAP_SUP_WIDTH;
				cap &= ~IEEE80211_HT_CAP_SGI_40;
			}
			break;
		case IEEE80211_HT_IE_CHA_SEC_BELOW:
			if (flags & IEEE80211_CHAN_NO_FAT_BELOW) {
				cap &= ~IEEE80211_HT_CAP_SUP_WIDTH;
				cap &= ~IEEE80211_HT_CAP_SGI_40;
			}
			break;
		}

		tmp = cpu_to_le16(cap);
		pos = skb_put(skb, sizeof(struct ieee80211_ht_cap)+2);
		*pos++ = WLAN_EID_HT_CAPABILITY;
		*pos++ = sizeof(struct ieee80211_ht_cap);
		memset(pos, 0, sizeof(struct ieee80211_ht_cap));
		memcpy(pos, &tmp, sizeof(u16));
		pos += sizeof(u16);
		/* TODO: needs a define here for << 2 */
		*pos++ = sband->ht_info.ampdu_factor |
			 (sband->ht_info.ampdu_density << 2);
		memcpy(pos, sband->ht_info.supp_mcs_set, 16);
	}

	kfree(ifsta->assocreq_ies);
	ifsta->assocreq_ies_len = (skb->data + skb->len) - ies;
	ifsta->assocreq_ies = kmalloc(ifsta->assocreq_ies_len, GFP_KERNEL);
	if (ifsta->assocreq_ies)
		memcpy(ifsta->assocreq_ies, ies, ifsta->assocreq_ies_len);

	ieee80211_sta_tx(dev, skb, 0);
}


static void ieee80211_send_deauth(struct net_device *dev,
				  struct ieee80211_if_sta *ifsta, u16 reason)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;

	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*mgmt));
	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer for deauth "
		       "frame\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	memcpy(mgmt->da, ifsta->bssid, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					   IEEE80211_STYPE_DEAUTH);
	skb_put(skb, 2);
	mgmt->u.deauth.reason_code = cpu_to_le16(reason);

	ieee80211_sta_tx(dev, skb, 0);
}


static void ieee80211_send_disassoc(struct net_device *dev,
				    struct ieee80211_if_sta *ifsta, u16 reason)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;

	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*mgmt));
	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer for disassoc "
		       "frame\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	memcpy(mgmt->da, ifsta->bssid, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					   IEEE80211_STYPE_DISASSOC);
	skb_put(skb, 2);
	mgmt->u.disassoc.reason_code = cpu_to_le16(reason);

	ieee80211_sta_tx(dev, skb, 0);
}


static int ieee80211_privacy_mismatch(struct net_device *dev,
				      struct ieee80211_if_sta *ifsta)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_sta_bss *bss;
	int bss_privacy;
	int wep_privacy;
	int privacy_invoked;

	if (!ifsta || (ifsta->flags & IEEE80211_STA_MIXED_CELL))
		return 0;

	bss = ieee80211_rx_bss_get(dev, ifsta->bssid,
				   local->hw.conf.channel->center_freq,
				   ifsta->ssid, ifsta->ssid_len);
	if (!bss)
		return 0;

	bss_privacy = !!(bss->capability & WLAN_CAPABILITY_PRIVACY);
	wep_privacy = !!ieee80211_sta_wep_configured(dev);
	privacy_invoked = !!(ifsta->flags & IEEE80211_STA_PRIVACY_INVOKED);

	ieee80211_rx_bss_put(local, bss);

	if ((bss_privacy == wep_privacy) || (bss_privacy == privacy_invoked))
		return 0;

	return 1;
}


static void ieee80211_associate(struct net_device *dev,
				struct ieee80211_if_sta *ifsta)
{
	DECLARE_MAC_BUF(mac);

	ifsta->assoc_tries++;
	if (ifsta->assoc_tries > IEEE80211_ASSOC_MAX_TRIES) {
		printk(KERN_DEBUG "%s: association with AP %s"
		       " timed out\n",
		       dev->name, print_mac(mac, ifsta->bssid));
		ifsta->state = IEEE80211_DISABLED;
		return;
	}

	ifsta->state = IEEE80211_ASSOCIATE;
	printk(KERN_DEBUG "%s: associate with AP %s\n",
	       dev->name, print_mac(mac, ifsta->bssid));
	if (ieee80211_privacy_mismatch(dev, ifsta)) {
		printk(KERN_DEBUG "%s: mismatch in privacy configuration and "
		       "mixed-cell disabled - abort association\n", dev->name);
		ifsta->state = IEEE80211_DISABLED;
		return;
	}

	ieee80211_send_assoc(dev, ifsta);

	mod_timer(&ifsta->timer, jiffies + IEEE80211_ASSOC_TIMEOUT);
}


static void ieee80211_associated(struct net_device *dev,
				 struct ieee80211_if_sta *ifsta)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sta_info *sta;
	int disassoc;
	DECLARE_MAC_BUF(mac);

	/* TODO: start monitoring current AP signal quality and number of
	 * missed beacons. Scan other channels every now and then and search
	 * for better APs. */
	/* TODO: remove expired BSSes */

	ifsta->state = IEEE80211_ASSOCIATED;

	rcu_read_lock();

	sta = sta_info_get(local, ifsta->bssid);
	if (!sta) {
		printk(KERN_DEBUG "%s: No STA entry for own AP %s\n",
		       dev->name, print_mac(mac, ifsta->bssid));
		disassoc = 1;
	} else {
		disassoc = 0;
		if (time_after(jiffies,
			       sta->last_rx + IEEE80211_MONITORING_INTERVAL)) {
			if (ifsta->flags & IEEE80211_STA_PROBEREQ_POLL) {
				printk(KERN_DEBUG "%s: No ProbeResp from "
				       "current AP %s - assume out of "
				       "range\n",
				       dev->name, print_mac(mac, ifsta->bssid));
				disassoc = 1;
				sta_info_unlink(&sta);
			} else
				ieee80211_send_probe_req(dev, ifsta->bssid,
							 local->scan_ssid,
							 local->scan_ssid_len);
			ifsta->flags ^= IEEE80211_STA_PROBEREQ_POLL;
		} else {
			ifsta->flags &= ~IEEE80211_STA_PROBEREQ_POLL;
			if (time_after(jiffies, ifsta->last_probe +
				       IEEE80211_PROBE_INTERVAL)) {
				ifsta->last_probe = jiffies;
				ieee80211_send_probe_req(dev, ifsta->bssid,
							 ifsta->ssid,
							 ifsta->ssid_len);
			}
		}
	}

	rcu_read_unlock();

	if (disassoc && sta)
		sta_info_destroy(sta);

	if (disassoc) {
		ifsta->state = IEEE80211_DISABLED;
		ieee80211_set_associated(dev, ifsta, 0);
	} else {
		mod_timer(&ifsta->timer, jiffies +
				      IEEE80211_MONITORING_INTERVAL);
	}
}


static void ieee80211_send_probe_req(struct net_device *dev, u8 *dst,
				     u8 *ssid, size_t ssid_len)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_supported_band *sband;
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u8 *pos, *supp_rates, *esupp_rates = NULL;
	int i;

	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*mgmt) + 200);
	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer for probe "
		       "request\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					   IEEE80211_STYPE_PROBE_REQ);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	if (dst) {
		memcpy(mgmt->da, dst, ETH_ALEN);
		memcpy(mgmt->bssid, dst, ETH_ALEN);
	} else {
		memset(mgmt->da, 0xff, ETH_ALEN);
		memset(mgmt->bssid, 0xff, ETH_ALEN);
	}
	pos = skb_put(skb, 2 + ssid_len);
	*pos++ = WLAN_EID_SSID;
	*pos++ = ssid_len;
	memcpy(pos, ssid, ssid_len);

	supp_rates = skb_put(skb, 2);
	supp_rates[0] = WLAN_EID_SUPP_RATES;
	supp_rates[1] = 0;
	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];

	for (i = 0; i < sband->n_bitrates; i++) {
		struct ieee80211_rate *rate = &sband->bitrates[i];
		if (esupp_rates) {
			pos = skb_put(skb, 1);
			esupp_rates[1]++;
		} else if (supp_rates[1] == 8) {
			esupp_rates = skb_put(skb, 3);
			esupp_rates[0] = WLAN_EID_EXT_SUPP_RATES;
			esupp_rates[1] = 1;
			pos = &esupp_rates[2];
		} else {
			pos = skb_put(skb, 1);
			supp_rates[1]++;
		}
		*pos = rate->bitrate / 5;
	}

	ieee80211_sta_tx(dev, skb, 0);
}


static int ieee80211_sta_wep_configured(struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	if (!sdata || !sdata->default_key ||
	    sdata->default_key->conf.alg != ALG_WEP)
		return 0;
	return 1;
}


static void ieee80211_auth_completed(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta)
{
	printk(KERN_DEBUG "%s: authenticated\n", dev->name);
	ifsta->flags |= IEEE80211_STA_AUTHENTICATED;
	ieee80211_associate(dev, ifsta);
}


static void ieee80211_auth_challenge(struct net_device *dev,
				     struct ieee80211_if_sta *ifsta,
				     struct ieee80211_mgmt *mgmt,
				     size_t len)
{
	u8 *pos;
	struct ieee802_11_elems elems;

	pos = mgmt->u.auth.variable;
	ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems);
	if (!elems.challenge)
		return;
	ieee80211_send_auth(dev, ifsta, 3, elems.challenge - 2,
			    elems.challenge_len + 2, 1);
}

static void ieee80211_send_addba_resp(struct net_device *dev, u8 *da, u16 tid,
					u8 dialog_token, u16 status, u16 policy,
					u16 buf_size, u16 timeout)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u16 capab;

	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);

	if (!skb) {
		printk(KERN_DEBUG "%s: failed to allocate buffer "
		       "for addba resp frame\n", dev->name);
		return;
	}

	skb_reserve(skb, local->hw.extra_tx_headroom);
	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	memcpy(mgmt->da, da, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	if (sdata->vif.type == IEEE80211_IF_TYPE_AP)
		memcpy(mgmt->bssid, dev->dev_addr, ETH_ALEN);
	else
		memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					   IEEE80211_STYPE_ACTION);

	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
	mgmt->u.action.category = WLAN_CATEGORY_BACK;
	mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
	mgmt->u.action.u.addba_resp.dialog_token = dialog_token;

	capab = (u16)(policy << 1);	/* bit 1 aggregation policy */
	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
	capab |= (u16)(buf_size << 6);	/* bit 15:6 max size of aggregation */

	mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
	mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
	mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);

	ieee80211_sta_tx(dev, skb, 0);

	return;
}

void ieee80211_send_addba_request(struct net_device *dev, const u8 *da,
				u16 tid, u8 dialog_token, u16 start_seq_num,
				u16 agg_size, u16 timeout)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	struct sk_buff *skb;
	struct ieee80211_mgmt *mgmt;
	u16 capab;

	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);

	if (!skb) {
		printk(KERN_ERR "%s: failed to allocate buffer "
				"for addba request frame\n", dev->name);
		return;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);
	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
	memset(mgmt, 0, 24);
	memcpy(mgmt->da, da, ETH_ALEN);
	memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
	if (sdata->vif.type == IEEE80211_IF_TYPE_AP)
		memcpy(mgmt->bssid, dev->dev_addr, ETH_ALEN);
	else
		memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);

	mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
					IEEE80211_STYPE_ACTION);

	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));

	mgmt->u.action.category = WLAN_CATEGORY_BACK;
	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;

	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
	capab = (u16)(1 << 1);		/* bit 1 aggregation policy */
	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
	capab |= (u16)(agg_size << 6);	/* bit 15:6 max size of aggergation */

	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);

	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
	mgmt->u.action.u.addba_req.start_seq_num =
					cpu_to_le16(start_seq_num << 4);

	ieee80211_sta_tx(dev, skb, 0);
}

static void ieee80211_sta_process_addba_request(struct net_device *dev,
						struct ieee80211_mgmt *mgmt,
						size_t len)
{
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_conf *conf = &hw->conf;
	struct sta_info *sta;
	struct tid_ampdu_rx *tid_agg_rx;
	u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
	u8 dialog_token;
	int ret = -EOPNOTSUPP;
	DECLARE_MAC_BUF(mac);

	rcu_read_lock();

	sta = sta_info_get(local, mgmt->sa);
	if (!sta) {
		rcu_read_unlock();
		return;
	}

	/* extract session parameters from addba request frame */
	dialog_token = mgmt->u.action.u.addba_req.dialog_token;
	timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
	start_seq_num =
		le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;

	capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
	ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;

	status = WLAN_STATUS_REQUEST_DECLINED;

	/* sanity check for incoming parameters:
	 * check if configuration can support the BA policy
	 * and if buffer size does not exceeds max value */
	if (((ba_policy != 1)
		&& (!(conf->ht_conf.cap & IEEE80211_HT_CAP_DELAY_BA)))
		|| (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
		status = WLAN_STATUS_INVALID_QOS_PARAM;
#ifdef CONFIG_MAC80211_HT_DEBUG
		if (net_ratelimit())
			printk(KERN_DEBUG "AddBA Req with bad params from "
				"%s on tid %u. policy %d, buffer size %d\n",
				print_mac(mac, mgmt->sa), tid, ba_policy,
				buf_size);
#endif /* CONFIG_MAC80211_HT_DEBUG */
		goto end_no_lock;
	}
	/* determine default buffer size */
	if (buf_size == 0) {
		struct ieee80211_supported_band *sband;

		sband = local->hw.wiphy->bands[conf->channel->band];
		buf_size = IEEE80211_MIN_AMPDU_BUF;
		buf_size = buf_size << sband->ht_info.ampdu_factor;
	}


	/* examine state machine */
	spin_lock_bh(&sta->lock);

	if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_IDLE) {
#ifdef CONFIG_MAC80211_HT_DEBUG
		if (net_ratelimit())
			printk(KERN_DEBUG "unexpected AddBA Req from "
				"%s on tid %u\n",
				print_mac(mac, mgmt->sa), tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
		goto end;
	}

	/* prepare A-MPDU MLME for Rx aggregation */
	sta->ampdu_mlme.tid_rx[tid] =
			kmalloc(sizeof(struct tid_ampdu_rx), GFP_ATOMIC);
	if (!sta->ampdu_mlme.tid_rx[tid]) {
#ifdef CONFIG_MAC80211_HT_DEBUG
		if (net_ratelimit())
			printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
					tid);
#endif
		goto end;
	}
	/* rx timer */
	sta->ampdu_mlme.tid_rx[tid]->session_timer.function =
				sta_rx_agg_session_timer_expired;
	sta->ampdu_mlme.tid_rx[tid]->session_timer.data =
				(unsigned long)&sta->timer_to_tid[tid];
	init_timer(&sta->ampdu_mlme.tid_rx[tid]->session_timer);

	tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];

	/* prepare reordering buffer */
	tid_agg_rx->reorder_buf =
		kmalloc(buf_size * sizeof(struct sk_buff *), GFP_ATOMIC);
	if (!tid_agg_rx->reorder_buf) {
#ifdef CONFIG_MAC80211_HT_DEBUG
		if (net_ratelimit())
			printk(KERN_ERR "can not allocate reordering buffer "
			       "to tid %d\n", tid);
#endif
		kfree(sta->ampdu_mlme.tid_rx[tid]);
		goto end;
	}
	memset(tid_agg_rx->reorder_buf, 0,
		buf_size * sizeof(struct sk_buff *));

	if (local->ops->ampdu_action)
		ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_RX_START,
					       sta->addr, tid, &start_seq_num);
#ifdef CONFIG_MAC80211_HT_DEBUG
	printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
#endif /* CONFIG_MAC80211_HT_DEBUG */

	if (ret) {
		kfree(tid_agg_rx->reorder_buf);
		kfree(tid_agg_rx);
		sta->ampdu_mlme.tid_rx[tid] = NULL;
		goto end;
	}

	/* change state and send addba resp */
	sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_OPERATIONAL;
	tid_agg_rx->dialog_token = dialog_token;
	tid_agg_rx->ssn = start_seq_num;
	tid_agg_rx->head_seq_num = start_seq_num;
	tid_agg_rx->buf_size = buf_size;
	tid_agg_rx->timeout = timeout;
	tid_agg_rx->stored_mpdu_num = 0;
	status = WLAN_STATUS_SUCCESS;
end:
	spin_unlock_bh(&sta->lock);