/*
   * 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>

   * Copyright (C) 2018        Intel Corporation

   *
   * 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/cfg80211.h>

  #include <net/mac80211.h>
  #include "ieee80211_i.h"
  #include "sta_info.h"
  #include "wme.h"

  int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,

  				 struct ieee802_11_elems *elems,

  				 enum nl80211_band current_band,

  				 u32 sta_flags, u8 *bssid,
  				 struct ieee80211_csa_ie *csa_ie)

  {

  	enum nl80211_band new_band = current_band;

  	int new_freq;
  	u8 new_chan_no;
  	struct ieee80211_channel *new_chan;
  	struct cfg80211_chan_def new_vht_chandef = {};
  	const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
  	const struct ieee80211_wide_bw_chansw_ie *wide_bw_chansw_ie;

  	int secondary_channel_offset = -1;

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

  	sec_chan_offs = elems->sec_chan_offs;
  	wide_bw_chansw_ie = elems->wide_bw_chansw_ie;

  
  	if (sta_flags & (IEEE80211_STA_DISABLE_HT |
  			 IEEE80211_STA_DISABLE_40MHZ)) {
  		sec_chan_offs = NULL;
  		wide_bw_chansw_ie = NULL;

  	}
  
  	if (sta_flags & IEEE80211_STA_DISABLE_VHT)
  		wide_bw_chansw_ie = NULL;
  
  	if (elems->ext_chansw_ie) {
  		if (!ieee80211_operating_class_to_band(
  				elems->ext_chansw_ie->new_operating_class,
  				&new_band)) {
  			sdata_info(sdata,

  				   "cannot understand ECSA IE operating class, %d, ignoring
  ",

  				   elems->ext_chansw_ie->new_operating_class);

  		}
  		new_chan_no = elems->ext_chansw_ie->new_ch_num;

  		csa_ie->count = elems->ext_chansw_ie->count;
  		csa_ie->mode = elems->ext_chansw_ie->mode;

  	} else if (elems->ch_switch_ie) {

  		new_chan_no = elems->ch_switch_ie->new_ch_num;

  		csa_ie->count = elems->ch_switch_ie->count;
  		csa_ie->mode = elems->ch_switch_ie->mode;

  	} else {
  		/* nothing here we understand */
  		return 1;
  	}

  	/* Mesh Channel Switch Parameters Element */
  	if (elems->mesh_chansw_params_ie) {
  		csa_ie->ttl = elems->mesh_chansw_params_ie->mesh_ttl;
  		csa_ie->mode = elems->mesh_chansw_params_ie->mesh_flags;

  		csa_ie->pre_value = le16_to_cpu(
  				elems->mesh_chansw_params_ie->mesh_pre_value);

  
  		if (elems->mesh_chansw_params_ie->mesh_flags &
  				WLAN_EID_CHAN_SWITCH_PARAM_REASON)
  			csa_ie->reason_code = le16_to_cpu(
  				elems->mesh_chansw_params_ie->mesh_reason);

  	}

  	new_freq = ieee80211_channel_to_frequency(new_chan_no, new_band);
  	new_chan = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
  	if (!new_chan || new_chan->flags & IEEE80211_CHAN_DISABLED) {
  		sdata_info(sdata,
  			   "BSS %pM switches to unsupported channel (%d MHz), disconnecting
  ",
  			   bssid, new_freq);
  		return -EINVAL;
  	}

  	if (sec_chan_offs) {

  		secondary_channel_offset = sec_chan_offs->sec_chan_offs;

  	} else if (!(sta_flags & IEEE80211_STA_DISABLE_HT)) {

  		/* If the secondary channel offset IE is not present,
  		 * we can't know what's the post-CSA offset, so the
  		 * best we can do is use 20MHz.
  		*/

  		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
  	}
  
  	switch (secondary_channel_offset) {
  	default:
  		/* secondary_channel_offset was present but is invalid */
  	case IEEE80211_HT_PARAM_CHA_SEC_NONE:

  		cfg80211_chandef_create(&csa_ie->chandef, new_chan,

  					NL80211_CHAN_HT20);
  		break;
  	case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:

  		cfg80211_chandef_create(&csa_ie->chandef, new_chan,

  					NL80211_CHAN_HT40PLUS);
  		break;
  	case IEEE80211_HT_PARAM_CHA_SEC_BELOW:

  		cfg80211_chandef_create(&csa_ie->chandef, new_chan,

  					NL80211_CHAN_HT40MINUS);
  		break;
  	case -1:

  		cfg80211_chandef_create(&csa_ie->chandef, new_chan,

  					NL80211_CHAN_NO_HT);
  		/* keep width for 5/10 MHz channels */
  		switch (sdata->vif.bss_conf.chandef.width) {
  		case NL80211_CHAN_WIDTH_5:
  		case NL80211_CHAN_WIDTH_10:

  			csa_ie->chandef.width =
  				sdata->vif.bss_conf.chandef.width;

  			break;
  		default:
  			break;
  		}
  		break;
  	}
  
  	if (wide_bw_chansw_ie) {

  		struct ieee80211_vht_operation vht_oper = {
  			.chan_width =
  				wide_bw_chansw_ie->new_channel_width,

  			.center_freq_seg0_idx =

  				wide_bw_chansw_ie->new_center_freq_seg0,

  			.center_freq_seg1_idx =

  				wide_bw_chansw_ie->new_center_freq_seg1,
  			/* .basic_mcs_set doesn't matter */
  		};

  		/* default, for the case of IEEE80211_VHT_CHANWIDTH_USE_HT,
  		 * to the previously parsed chandef
  		 */
  		new_vht_chandef = csa_ie->chandef;
  
  		/* ignore if parsing fails */
  		if (!ieee80211_chandef_vht_oper(&vht_oper, &new_vht_chandef))

  			new_vht_chandef.chan = NULL;

  		if (sta_flags & IEEE80211_STA_DISABLE_80P80MHZ &&
  		    new_vht_chandef.width == NL80211_CHAN_WIDTH_80P80)
  			ieee80211_chandef_downgrade(&new_vht_chandef);
  		if (sta_flags & IEEE80211_STA_DISABLE_160MHZ &&
  		    new_vht_chandef.width == NL80211_CHAN_WIDTH_160)
  			ieee80211_chandef_downgrade(&new_vht_chandef);

  	}
  
  	/* if VHT data is there validate & use it */
  	if (new_vht_chandef.chan) {
  		if (!cfg80211_chandef_compatible(&new_vht_chandef,

  						 &csa_ie->chandef)) {

  			sdata_info(sdata,
  				   "BSS %pM: CSA has inconsistent channel data, disconnecting
  ",
  				   bssid);
  			return -EINVAL;
  		}

  		csa_ie->chandef = new_vht_chandef;

  	}
  
  	return 0;
  }

  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)

  		return;

  
  	skb_reserve(skb, local->hw.extra_tx_headroom);

  	msr_report = skb_put_zero(skb, 24);

  	memcpy(msr_report->da, da, ETH_ALEN);

  	memcpy(msr_report->sa, sdata->vif.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);

  }
  
  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);
  }