/*
 * spectrum management
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2007-2008, Intel Corporation
 * 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/ieee80211.h>
#include <net/wireless.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "sta_info.h"
#include "wme.h"

static void ieee80211_send_refuse_measurement_request(struct ieee80211_sub_if_data *sdata,
					struct ieee80211_msrment_ie *request_ie,
					const u8 *da, const u8 *bssid,
					u8 dialog_token)
{
	struct ieee80211_local *local = sdata->local;
	struct sk_buff *skb;
	struct ieee80211_mgmt *msr_report;

	skb = dev_alloc_skb(sizeof(*msr_report) + local->hw.extra_tx_headroom +
				sizeof(struct ieee80211_msrment_ie));

	if (!skb) {
		printk(KERN_ERR "%s: failed to allocate buffer for "
				"measurement report frame\n", sdata->dev->name);
		return;
	}

	skb_reserve(skb, local->hw.extra_tx_headroom);
	msr_report = (struct ieee80211_mgmt *)skb_put(skb, 24);
	memset(msr_report, 0, 24);
	memcpy(msr_report->da, da, ETH_ALEN);
	memcpy(msr_report->sa, sdata->dev->dev_addr, ETH_ALEN);
	memcpy(msr_report->bssid, bssid, ETH_ALEN);
	msr_report->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
						IEEE80211_STYPE_ACTION);

	skb_put(skb, 1 + sizeof(msr_report->u.action.u.measurement));
	msr_report->u.action.category = WLAN_CATEGORY_SPECTRUM_MGMT;
	msr_report->u.action.u.measurement.action_code =
				WLAN_ACTION_SPCT_MSR_RPRT;
	msr_report->u.action.u.measurement.dialog_token = dialog_token;

	msr_report->u.action.u.measurement.element_id = WLAN_EID_MEASURE_REPORT;
	msr_report->u.action.u.measurement.length =
			sizeof(struct ieee80211_msrment_ie);

	memset(&msr_report->u.action.u.measurement.msr_elem, 0,
		sizeof(struct ieee80211_msrment_ie));
	msr_report->u.action.u.measurement.msr_elem.token = request_ie->token;
	msr_report->u.action.u.measurement.msr_elem.mode |=
			IEEE80211_SPCT_MSR_RPRT_MODE_REFUSED;
	msr_report->u.action.u.measurement.msr_elem.type = request_ie->type;

	ieee80211_tx_skb(sdata, skb, 1);
}

void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,
				       struct ieee80211_mgmt *mgmt,
				       size_t len)
{
	/*
	 * Ignoring measurement request is spec violation.
	 * Mandatory measurements must be reported optional
	 * measurements might be refused or reported incapable
	 * For now just refuse
	 * TODO: Answer basic measurement as unmeasured
	 */
	ieee80211_send_refuse_measurement_request(sdata,
			&mgmt->u.action.u.measurement.msr_elem,
			mgmt->sa, mgmt->bssid,
			mgmt->u.action.u.measurement.dialog_token);
}

void ieee80211_chswitch_work(struct work_struct *work)
{
	struct ieee80211_sub_if_data *sdata =
		container_of(work, struct ieee80211_sub_if_data, u.mgd.chswitch_work);
	struct ieee80211_bss *bss;
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

	if (!netif_running(sdata->dev))
		return;

	bss = ieee80211_rx_bss_get(sdata->local, ifmgd->bssid,
				   sdata->local->hw.conf.channel->center_freq,
				   ifmgd->ssid, ifmgd->ssid_len);
	if (!bss)
		goto exit;

	sdata->local->oper_channel = sdata->local->csa_channel;
	/* XXX: shouldn't really modify cfg80211-owned data! */
	if (!ieee80211_hw_config(sdata->local, IEEE80211_CONF_CHANGE_CHANNEL))
		bss->cbss.channel = sdata->local->oper_channel;

	ieee80211_rx_bss_put(sdata->local, bss);
exit:
	ifmgd->flags &= ~IEEE80211_STA_CSA_RECEIVED;
	ieee80211_wake_queues_by_reason(&sdata->local->hw,
					IEEE80211_QUEUE_STOP_REASON_CSA);
}

void ieee80211_chswitch_timer(unsigned long data)
{
	struct ieee80211_sub_if_data *sdata =
		(struct ieee80211_sub_if_data *) data;
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

	queue_work(sdata->local->hw.workqueue, &ifmgd->chswitch_work);
}

void ieee80211_process_chanswitch(struct ieee80211_sub_if_data *sdata,
				  struct ieee80211_channel_sw_ie *sw_elem,
				  struct ieee80211_bss *bss)
{
	struct ieee80211_channel *new_ch;
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
	int new_freq = ieee80211_channel_to_frequency(sw_elem->new_ch_num);

	/* FIXME: Handle ADHOC later */
	if (sdata->vif.type != NL80211_IFTYPE_STATION)
		return;

	if (ifmgd->state != IEEE80211_STA_MLME_ASSOCIATED)
		return;

	if (sdata->local->sw_scanning || sdata->local->hw_scanning)
		return;

	/* Disregard subsequent beacons if we are already running a timer
	   processing a CSA */

	if (ifmgd->flags & IEEE80211_STA_CSA_RECEIVED)
		return;

	new_ch = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
	if (!new_ch || new_ch->flags & IEEE80211_CHAN_DISABLED)
		return;

	sdata->local->csa_channel = new_ch;

	if (sw_elem->count <= 1) {
		queue_work(sdata->local->hw.workqueue, &ifmgd->chswitch_work);
	} else {
		ieee80211_stop_queues_by_reason(&sdata->local->hw,
						IEEE80211_QUEUE_STOP_REASON_CSA);
		ifmgd->flags |= IEEE80211_STA_CSA_RECEIVED;
		mod_timer(&ifmgd->chswitch_timer,
			  jiffies +
			  msecs_to_jiffies(sw_elem->count *
					   bss->cbss.beacon_interval));
	}
}

void ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,
				 u16 capab_info, u8 *pwr_constr_elem,
				 u8 pwr_constr_elem_len)
{
	struct ieee80211_conf *conf = &sdata->local->hw.conf;

	if (!(capab_info & WLAN_CAPABILITY_SPECTRUM_MGMT))
		return;

	/* Power constraint IE length should be 1 octet */
	if (pwr_constr_elem_len != 1)
		return;

	if ((*pwr_constr_elem <= conf->channel->max_power) &&
	    (*pwr_constr_elem != sdata->local->power_constr_level)) {
		sdata->local->power_constr_level = *pwr_constr_elem;
		ieee80211_hw_config(sdata->local, 0);
	}
}