hostap/src/ap/hw_features.c - nest-learning-thermostat/5.6.2/hostap - Git at Google

 /*
  * hostapd / Hardware feature query and different modes
  * Copyright 2002-2003, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright (c) 2008-2012, Jouni Malinen <j@w1.fi>
  *
  * 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.
  *
  * Alternatively, this software may be distributed under the terms of BSD
  * license.
  *
  * See README and COPYING for more details.
  */

 #include "utils/includes.h"

 #include "utils/common.h"
 #include "utils/eloop.h"
 #include "common/ieee802_11_defs.h"
 #include "common/ieee802_11_common.h"
 #include "drivers/driver.h"
 #include "hostapd.h"
 #include "ap_config.h"
 #include "ap_drv_ops.h"
 #include "hw_features.h"


 void hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
 			      size_t num_hw_features)
 {
 	size_t i;

 	if (hw_features == NULL)
 		return;

 	for (i = 0; i < num_hw_features; i++) {
 		os_free(hw_features[i].channels);
 		os_free(hw_features[i].rates);
 	}

 	os_free(hw_features);
 }


 int hostapd_get_hw_features(struct hostapd_iface *iface)
 {
 	struct hostapd_data *hapd = iface->bss[0];
 	int ret = 0, i, j;
 	u16 num_modes, flags;
 	struct hostapd_hw_modes *modes;

 	if (hostapd_drv_none(hapd))
 		return -1;
 	modes = hostapd_get_hw_feature_data(hapd, &num_modes, &flags);
 	if (modes == NULL) {
 		hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
 			       HOSTAPD_LEVEL_DEBUG,
 			       "Fetching hardware channel/rate support not "
 			       "supported.");
 		return -1;
 	}

 	iface->hw_flags = flags;

 	hostapd_free_hw_features(iface->hw_features, iface->num_hw_features);
 	iface->hw_features = modes;
 	iface->num_hw_features = num_modes;

 	for (i = 0; i < num_modes; i++) {
 		struct hostapd_hw_modes *feature = &modes[i];
 		/* set flag for channels we can use in current regulatory
 		 * domain */
 		for (j = 0; j < feature->num_channels; j++) {
 			/*
 			 * Disable all channels that are marked not to allow
 			 * IBSS operation or active scanning. In addition,
 			 * disable all channels that require radar detection,
 			 * since that (in addition to full DFS) is not yet
 			 * supported.
 			 */
 			if (feature->channels[j].flag &
 			    (HOSTAPD_CHAN_NO_IBSS |
 			     HOSTAPD_CHAN_PASSIVE_SCAN |
 			     HOSTAPD_CHAN_RADAR))
 				feature->channels[j].flag |=
 					HOSTAPD_CHAN_DISABLED;
 			if (feature->channels[j].flag & HOSTAPD_CHAN_DISABLED)
 				continue;
 			wpa_printf(MSG_MSGDUMP, "Allowed channel: mode=%d "
 				   "chan=%d freq=%d MHz max_tx_power=%d dBm",
 				   feature->mode,
 				   feature->channels[j].chan,
 				   feature->channels[j].freq,
 				   feature->channels[j].max_tx_power);
 		}
 	}

 	return ret;
 }


 int hostapd_prepare_rates(struct hostapd_iface *iface,
 			  struct hostapd_hw_modes *mode)
 {
 	int i, num_basic_rates = 0;
 	int basic_rates_a[] = { 60, 120, 240, -1 };
 	int basic_rates_b[] = { 10, 20, -1 };
 	int basic_rates_g[] = { 10, 20, 55, 110, -1 };
 	int *basic_rates;

 	if (iface->conf->basic_rates)
 		basic_rates = iface->conf->basic_rates;
 	else switch (mode->mode) {
 	case HOSTAPD_MODE_IEEE80211A:
 		basic_rates = basic_rates_a;
 		break;
 	case HOSTAPD_MODE_IEEE80211B:
 		basic_rates = basic_rates_b;
 		break;
 	case HOSTAPD_MODE_IEEE80211G:
 		basic_rates = basic_rates_g;
 		break;
 	case HOSTAPD_MODE_IEEE80211AD:
 		return 0; /* No basic rates for 11ad */
 	default:
 		return -1;
 	}

 	i = 0;
 	while (basic_rates[i] >= 0)
 		i++;
 	if (i)
 		i++; /* -1 termination */
 	os_free(iface->basic_rates);
 	iface->basic_rates = os_malloc(i * sizeof(int));
 	if (iface->basic_rates)
 		os_memcpy(iface->basic_rates, basic_rates, i * sizeof(int));

 	os_free(iface->current_rates);
 	iface->num_rates = 0;

 	iface->current_rates =
 		os_calloc(mode->num_rates, sizeof(struct hostapd_rate_data));
 	if (!iface->current_rates) {
 		wpa_printf(MSG_ERROR, "Failed to allocate memory for rate "
 			   "table.");
 		return -1;
 	}

 	for (i = 0; i < mode->num_rates; i++) {
 		struct hostapd_rate_data *rate;

 		if (iface->conf->supported_rates &&
 		    !hostapd_rate_found(iface->conf->supported_rates,
 					mode->rates[i]))
 			continue;

 		rate = &iface->current_rates[iface->num_rates];
 		rate->rate = mode->rates[i];
 		if (hostapd_rate_found(basic_rates, rate->rate)) {
 			rate->flags |= HOSTAPD_RATE_BASIC;
 			num_basic_rates++;
 		}
 		wpa_printf(MSG_DEBUG, "RATE[%d] rate=%d flags=0x%x",
 			   iface->num_rates, rate->rate, rate->flags);
 		iface->num_rates++;
 	}

 	if ((iface->num_rates == 0 || num_basic_rates == 0) &&
 	    (!iface->conf->ieee80211n || !iface->conf->require_ht)) {
 		wpa_printf(MSG_ERROR, "No rates remaining in supported/basic "
 			   "rate sets (%d,%d).",
 			   iface->num_rates, num_basic_rates);
 		return -1;
 	}

 	return 0;
 }


 #ifdef CONFIG_IEEE80211N
 static int ieee80211n_allowed_ht40_channel_pair(struct hostapd_iface *iface)
 {
 	int sec_chan, ok, j, first;
 	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
 			  184, 192 };
 	size_t k;

 	if (!iface->conf->secondary_channel)
 		return 1; /* HT40 not used */

 	sec_chan = iface->conf->channel + iface->conf->secondary_channel * 4;
 	wpa_printf(MSG_DEBUG, "HT40: control channel: %d  "
 		   "secondary channel: %d",
 		   iface->conf->channel, sec_chan);

 	/* Verify that HT40 secondary channel is an allowed 20 MHz
 	 * channel */
 	ok = 0;
 	for (j = 0; j < iface->current_mode->num_channels; j++) {
 		struct hostapd_channel_data *chan =
 			&iface->current_mode->channels[j];
 		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
 		    chan->chan == sec_chan) {
 			ok = 1;
 			break;
 		}
 	}
 	if (!ok) {
 		wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
 			   sec_chan);
 		return 0;
 	}

 	/*
 	 * Verify that HT40 primary,secondary channel pair is allowed per
 	 * IEEE 802.11n Annex J. This is only needed for 5 GHz band since
 	 * 2.4 GHz rules allow all cases where the secondary channel fits into
 	 * the list of allowed channels (already checked above).
 	 */
 	if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
 		return 1;

 	if (iface->conf->secondary_channel > 0)
 		first = iface->conf->channel;
 	else
 		first = sec_chan;

 	ok = 0;
 	for (k = 0; k < sizeof(allowed) / sizeof(allowed[0]); k++) {
 		if (first == allowed[k]) {
 			ok = 1;
 			break;
 		}
 	}
 	if (!ok) {
 		wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
 			   iface->conf->channel,
 			   iface->conf->secondary_channel);
 		return 0;
 	}

 	return 1;
 }


 static void ieee80211n_switch_pri_sec(struct hostapd_iface *iface)
 {
 	if (iface->conf->secondary_channel > 0) {
 		iface->conf->channel += 4;
 		iface->conf->secondary_channel = -1;
 	} else {
 		iface->conf->channel -= 4;
 		iface->conf->secondary_channel = 1;
 	}
 }


 static void ieee80211n_get_pri_sec_chan(struct wpa_scan_res *bss,
 					int *pri_chan, int *sec_chan)
 {
 	struct ieee80211_ht_operation *oper;
 	struct ieee802_11_elems elems;

 	*pri_chan = *sec_chan = 0;

 	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
 	if (elems.ht_operation &&
 	    elems.ht_operation_len >= sizeof(*oper)) {
 		oper = (struct ieee80211_ht_operation *) elems.ht_operation;
 		*pri_chan = oper->control_chan;
 		if (oper->ht_param & HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH) {
 			int sec = oper->ht_param &
 				HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK;
 			if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE)
 				*sec_chan = *pri_chan + 4;
 			else if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW)
 				*sec_chan = *pri_chan - 4;
 		}
 	}
 }


 static int ieee80211n_check_40mhz_5g(struct hostapd_iface *iface,
 				     struct wpa_scan_results *scan_res)
 {
 	int pri_chan, sec_chan, pri_freq, sec_freq, pri_bss, sec_bss;
 	int bss_pri_chan, bss_sec_chan;
 	size_t i;
 	int match;

 	pri_chan = iface->conf->channel;
 	sec_chan = iface->conf->secondary_channel * 4;
 	pri_freq = hostapd_hw_get_freq(iface->bss[0], pri_chan);
 	if (iface->conf->secondary_channel > 0)
 		sec_freq = pri_freq + 20;
 	else
 		sec_freq = pri_freq - 20;

 	/*
 	 * Switch PRI/SEC channels if Beacons were detected on selected SEC
 	 * channel, but not on selected PRI channel.
 	 */
 	pri_bss = sec_bss = 0;
 	for (i = 0; i < scan_res->num; i++) {
 		struct wpa_scan_res *bss = scan_res->res[i];
 		if (bss->freq == pri_freq)
 			pri_bss++;
 		else if (bss->freq == sec_freq)
 			sec_bss++;
 	}
 	if (sec_bss && !pri_bss) {
 		wpa_printf(MSG_INFO, "Switch own primary and secondary "
 			   "channel to get secondary channel with no Beacons "
 			   "from other BSSes");
 		ieee80211n_switch_pri_sec(iface);
 	}

 	/*
 	 * Match PRI/SEC channel with any existing HT40 BSS on the same
 	 * channels that we are about to use (if already mixed order in
 	 * existing BSSes, use own preference).
 	 */
 	match = 0;
 	for (i = 0; i < scan_res->num; i++) {
 		struct wpa_scan_res *bss = scan_res->res[i];
 		ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
 		if (pri_chan == bss_pri_chan &&
 		    sec_chan == bss_sec_chan) {
 			match = 1;
 			break;
 		}
 	}
 	if (!match) {
 		for (i = 0; i < scan_res->num; i++) {
 			struct wpa_scan_res *bss = scan_res->res[i];
 			ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan,
 						    &bss_sec_chan);
 			if (pri_chan == bss_sec_chan &&
 			    sec_chan == bss_pri_chan) {
 				wpa_printf(MSG_INFO, "Switch own primary and "
 					   "secondary channel due to BSS "
 					   "overlap with " MACSTR,
 					   MAC2STR(bss->bssid));
 				ieee80211n_switch_pri_sec(iface);
 				break;
 			}
 		}
 	}

 	return 1;
 }


 static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
 				      struct wpa_scan_results *scan_res)
 {
 	int pri_freq, sec_freq;
 	int affected_start, affected_end;
 	size_t i;

 	pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
 	if (iface->conf->secondary_channel > 0)
 		sec_freq = pri_freq + 20;
 	else
 		sec_freq = pri_freq - 20;
 	affected_start = (pri_freq + sec_freq) / 2 - 25;
 	affected_end = (pri_freq + sec_freq) / 2 + 25;
 	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
 		   affected_start, affected_end);
 	for (i = 0; i < scan_res->num; i++) {
 		struct wpa_scan_res *bss = scan_res->res[i];
 		int pri = bss->freq;
 		int sec = pri;
 		int sec_chan, pri_chan;

 		ieee80211n_get_pri_sec_chan(bss, &pri_chan, &sec_chan);

 		if (sec_chan) {
 			if (sec_chan < pri_chan)
 				sec = pri - 20;
 			else
 				sec = pri + 20;
 		}

 		if ((pri < affected_start || pri > affected_end) &&
 		    (sec < affected_start || sec > affected_end))
 			continue; /* not within affected channel range */

 		wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
 			   " freq=%d pri=%d sec=%d",
 			   MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);

 		if (sec_chan) {
 			if (pri_freq != pri || sec_freq != sec) {
 				wpa_printf(MSG_DEBUG, "40 MHz pri/sec "
 					   "mismatch with BSS " MACSTR
 					   " <%d,%d> (chan=%d%c) vs. <%d,%d>",
 					   MAC2STR(bss->bssid),
 					   pri, sec, pri_chan,
 					   sec > pri ? '+' : '-',
 					   pri_freq, sec_freq);
 				return 0;
 			}
 		}

 		/* TODO: 40 MHz intolerant */
 	}

 	return 1;
 }


 static void ieee80211n_check_scan(struct hostapd_iface *iface)
 {
 	struct wpa_scan_results *scan_res;
 	int oper40;
 	int res;

 	/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
 	 * allowed per IEEE Std 802.11-2012, 10.15.3.2 */

 	iface->scan_cb = NULL;

 	scan_res = hostapd_driver_get_scan_results(iface->bss[0]);
 	if (scan_res == NULL) {
 		hostapd_setup_interface_complete(iface, 1);
 		return;
 	}

 	if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A)
 		oper40 = ieee80211n_check_40mhz_5g(iface, scan_res);
 	else
 		oper40 = ieee80211n_check_40mhz_2g4(iface, scan_res);
 	wpa_scan_results_free(scan_res);

 	if (!oper40) {
 		wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
 			   "channel pri=%d sec=%d based on overlapping BSSes",
 			   iface->conf->channel,
 			   iface->conf->channel +
 			   iface->conf->secondary_channel * 4);
 		iface->conf->secondary_channel = 0;
 		iface->conf->ht_capab &= ~HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET;
 	}

 	res = ieee80211n_allowed_ht40_channel_pair(iface);
 	hostapd_setup_interface_complete(iface, !res);
 }


 static void ieee80211n_scan_channels_2g4(struct hostapd_iface *iface,
 					 struct wpa_driver_scan_params *params)
 {
 	/* Scan only the affected frequency range */
 	int pri_freq, sec_freq;
 	int affected_start, affected_end;
 	int i, pos;
 	struct hostapd_hw_modes *mode;

 	if (iface->current_mode == NULL)
 		return;

 	pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
 	if (iface->conf->secondary_channel > 0)
 		sec_freq = pri_freq + 20;
 	else
 		sec_freq = pri_freq - 20;
 	affected_start = (pri_freq + sec_freq) / 2 - 25;
 	affected_end = (pri_freq + sec_freq) / 2 + 25;
 	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
 		   affected_start, affected_end);

 	mode = iface->current_mode;
 	params->freqs = os_calloc(mode->num_channels + 1, sizeof(int));
 	if (params->freqs == NULL)
 		return;
 	pos = 0;

 	for (i = 0; i < mode->num_channels; i++) {
 		struct hostapd_channel_data *chan = &mode->channels[i];
 		if (chan->flag & HOSTAPD_CHAN_DISABLED)
 			continue;
 		if (chan->freq < affected_start ||
 		    chan->freq > affected_end)
 			continue;
 		params->freqs[pos++] = chan->freq;
 	}
 }


 static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
 {
 	struct wpa_driver_scan_params params;

 	if (!iface->conf->secondary_channel)
 		return 0; /* HT40 not used */

 	wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling "
 		   "40 MHz channel");
 	os_memset(&params, 0, sizeof(params));
 	if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G)
 		ieee80211n_scan_channels_2g4(iface, &params);
 	if (hostapd_driver_scan(iface->bss[0], &params) < 0) {
 		wpa_printf(MSG_ERROR, "Failed to request a scan of "
 			   "neighboring BSSes");
 		os_free(params.freqs);
 		return -1;
 	}
 	os_free(params.freqs);

 	iface->scan_cb = ieee80211n_check_scan;
 	return 1;
 }


 static int ieee80211n_supported_ht_capab(struct hostapd_iface *iface)
 {
 	u16 hw = iface->current_mode->ht_capab;
 	u16 conf = iface->conf->ht_capab;

 	if ((conf & HT_CAP_INFO_LDPC_CODING_CAP) &&
 	    !(hw & HT_CAP_INFO_LDPC_CODING_CAP)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [LDPC]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) &&
 	    !(hw & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [HT40*]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_SMPS_MASK) != (hw & HT_CAP_INFO_SMPS_MASK) &&
 	    (conf & HT_CAP_INFO_SMPS_MASK) != HT_CAP_INFO_SMPS_DISABLED) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [SMPS-*]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_GREEN_FIELD) &&
 	    !(hw & HT_CAP_INFO_GREEN_FIELD)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [GF]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_SHORT_GI20MHZ) &&
 	    !(hw & HT_CAP_INFO_SHORT_GI20MHZ)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [SHORT-GI-20]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_SHORT_GI40MHZ) &&
 	    !(hw & HT_CAP_INFO_SHORT_GI40MHZ)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [SHORT-GI-40]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_TX_STBC) && !(hw & HT_CAP_INFO_TX_STBC)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [TX-STBC]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_RX_STBC_MASK) >
 	    (hw & HT_CAP_INFO_RX_STBC_MASK)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [RX-STBC*]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_DELAYED_BA) &&
 	    !(hw & HT_CAP_INFO_DELAYED_BA)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [DELAYED-BA]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_MAX_AMSDU_SIZE) &&
 	    !(hw & HT_CAP_INFO_MAX_AMSDU_SIZE)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [MAX-AMSDU-7935]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_DSSS_CCK40MHZ) &&
 	    !(hw & HT_CAP_INFO_DSSS_CCK40MHZ)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [DSSS_CCK-40]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_PSMP_SUPP) && !(hw & HT_CAP_INFO_PSMP_SUPP)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [PSMP]");
 		return 0;
 	}

 	if ((conf & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT) &&
 	    !(hw & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT)) {
 		wpa_printf(MSG_ERROR, "Driver does not support configured "
 			   "HT capability [LSIG-TXOP-PROT]");
 		return 0;
 	}

 	return 1;
 }

 #endif /* CONFIG_IEEE80211N */


 int hostapd_check_ht_capab(struct hostapd_iface *iface)
 {
 #ifdef CONFIG_IEEE80211N
 	int ret;
 	if (!iface->conf->ieee80211n)
 		return 0;
 	if (!ieee80211n_supported_ht_capab(iface))
 		return -1;
 	ret = ieee80211n_check_40mhz(iface);
 	if (ret)
 		return ret;
 	if (!ieee80211n_allowed_ht40_channel_pair(iface))
 		return -1;
 #endif /* CONFIG_IEEE80211N */

 	return 0;
 }


 /**
  * hostapd_select_hw_mode - Select the hardware mode
  * @iface: Pointer to interface data.
  * Returns: 0 on success, < 0 on failure
  *
  * Sets up the hardware mode, channel, rates, and passive scanning
  * based on the configuration.
  */
 int hostapd_select_hw_mode(struct hostapd_iface *iface)
 {
 	int i, j, ok;

 	if (iface->num_hw_features < 1)
 		return -1;

 	iface->current_mode = NULL;
 	for (i = 0; i < iface->num_hw_features; i++) {
 		struct hostapd_hw_modes *mode = &iface->hw_features[i];
 		if (mode->mode == iface->conf->hw_mode) {
 			iface->current_mode = mode;
 			break;
 		}
 	}

 	if (iface->current_mode == NULL) {
 		wpa_printf(MSG_ERROR, "Hardware does not support configured "
 			   "mode");
 		hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
 			       HOSTAPD_LEVEL_WARNING,
 			       "Hardware does not support configured mode "
 			       "(%d) (hw_mode in hostapd.conf)",
 			       (int) iface->conf->hw_mode);
 		return -2;
 	}

 	ok = 0;
 	for (j = 0; j < iface->current_mode->num_channels; j++) {
 		struct hostapd_channel_data *chan =
 			&iface->current_mode->channels[j];
 		if (chan->chan == iface->conf->channel) {
 			if (chan->flag & HOSTAPD_CHAN_DISABLED) {
 				wpa_printf(MSG_ERROR,
 					   "channel [%i] (%i) is disabled for "
 					   "use in AP mode, flags: 0x%x%s%s%s",
 					   j, chan->chan, chan->flag,
 					   chan->flag & HOSTAPD_CHAN_NO_IBSS ?
 					   " NO-IBSS" : "",
 					   chan->flag &
 					   HOSTAPD_CHAN_PASSIVE_SCAN ?
 					   " PASSIVE-SCAN" : "",
 					   chan->flag & HOSTAPD_CHAN_RADAR ?
 					   " RADAR" : "");
 			} else {
 				ok = 1;
 				break;
 			}
 		}
 	}
 	if (ok && iface->conf->secondary_channel) {
 		int sec_ok = 0;
 		int sec_chan = iface->conf->channel +
 			iface->conf->secondary_channel * 4;
 		for (j = 0; j < iface->current_mode->num_channels; j++) {
 			struct hostapd_channel_data *chan =
 				&iface->current_mode->channels[j];
 			if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
 			    (chan->chan == sec_chan)) {
 				sec_ok = 1;
 				break;
 			}
 		}
 		if (!sec_ok) {
 			hostapd_logger(iface->bss[0], NULL,
 				       HOSTAPD_MODULE_IEEE80211,
 				       HOSTAPD_LEVEL_WARNING,
 				       "Configured HT40 secondary channel "
 				       "(%d) not found from the channel list "
 				       "of current mode (%d) %s",
 				       sec_chan, iface->current_mode->mode,
 				       hostapd_hw_mode_txt(
 					       iface->current_mode->mode));
 			ok = 0;
 		}
 	}
 	if (iface->conf->channel == 0) {
 		/* TODO: could request a scan of neighboring BSSes and select
 		 * the channel automatically */
 		wpa_printf(MSG_ERROR, "Channel not configured "
 			   "(hw_mode/channel in hostapd.conf)");
 		return -3;
 	}
 	if (ok == 0 && iface->conf->channel != 0) {
 		hostapd_logger(iface->bss[0], NULL,
 			       HOSTAPD_MODULE_IEEE80211,
 			       HOSTAPD_LEVEL_WARNING,
 			       "Configured channel (%d) not found from the "
 			       "channel list of current mode (%d) %s",
 			       iface->conf->channel,
 			       iface->current_mode->mode,
 			       hostapd_hw_mode_txt(iface->current_mode->mode));
 		iface->current_mode = NULL;
 	}

 	if (iface->current_mode == NULL) {
 		hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
 			       HOSTAPD_LEVEL_WARNING,
 			       "Hardware does not support configured channel");
 		return -4;
 	}

 	return 0;
 }


 const char * hostapd_hw_mode_txt(int mode)
 {
 	switch (mode) {
 	case HOSTAPD_MODE_IEEE80211A:
 		return "IEEE 802.11a";
 	case HOSTAPD_MODE_IEEE80211B:
 		return "IEEE 802.11b";
 	case HOSTAPD_MODE_IEEE80211G:
 		return "IEEE 802.11g";
 	case HOSTAPD_MODE_IEEE80211AD:
 		return "IEEE 802.11ad";
 	default:
 		return "UNKNOWN";
 	}
 }


 int hostapd_hw_get_freq(struct hostapd_data *hapd, int chan)
 {
 	int i;

 	if (!hapd->iface->current_mode)
 		return 0;

 	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
 		struct hostapd_channel_data *ch =
 			&hapd->iface->current_mode->channels[i];
 		if (ch->chan == chan)
 			return ch->freq;
 	}

 	return 0;
 }


 int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
 {
 	int i;

 	if (!hapd->iface->current_mode)
 		return 0;

 	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
 		struct hostapd_channel_data *ch =
 			&hapd->iface->current_mode->channels[i];
 		if (ch->freq == freq)
 			return ch->chan;
 	}

 	return 0;
 }

 int hostapd_hw_get_channel_flag(struct hostapd_data *hapd, int chan)
 {
 	int i;

 	if (!hapd->iface->current_mode)
 		return 0;

 	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
 		struct hostapd_channel_data *ch =
 			&hapd->iface->current_mode->channels[i];
 		if (ch->chan == chan)
 			return ch->flag;
 	}

 	return 0;
 }
	/*
	* hostapd / Hardware feature query and different modes
	* Copyright 2002-2003, Instant802 Networks, Inc.
	* Copyright 2005-2006, Devicescape Software, Inc.
	* Copyright (c) 2008-2012, Jouni Malinen <j@w1.fi>
	*
	* 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.
	*
	* Alternatively, this software may be distributed under the terms of BSD
	* license.
	*
	* See README and COPYING for more details.
	*/

	#include "utils/includes.h"

	#include "utils/common.h"
	#include "utils/eloop.h"
	#include "common/ieee802_11_defs.h"
	#include "common/ieee802_11_common.h"
	#include "drivers/driver.h"
	#include "hostapd.h"
	#include "ap_config.h"
	#include "ap_drv_ops.h"
	#include "hw_features.h"


	void hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
	size_t num_hw_features)
	{
	size_t i;

	if (hw_features == NULL)
	return;

	for (i = 0; i < num_hw_features; i++) {
	os_free(hw_features[i].channels);
	os_free(hw_features[i].rates);
	}

	os_free(hw_features);
	}


	int hostapd_get_hw_features(struct hostapd_iface *iface)
	{
	struct hostapd_data *hapd = iface->bss[0];
	int ret = 0, i, j;
	u16 num_modes, flags;
	struct hostapd_hw_modes *modes;

	if (hostapd_drv_none(hapd))
	return -1;
	modes = hostapd_get_hw_feature_data(hapd, &num_modes, &flags);
	if (modes == NULL) {
	hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
	HOSTAPD_LEVEL_DEBUG,
	"Fetching hardware channel/rate support not "
	"supported.");
	return -1;
	}

	iface->hw_flags = flags;

	hostapd_free_hw_features(iface->hw_features, iface->num_hw_features);
	iface->hw_features = modes;
	iface->num_hw_features = num_modes;

	for (i = 0; i < num_modes; i++) {
	struct hostapd_hw_modes *feature = &modes[i];
	/* set flag for channels we can use in current regulatory
	* domain */
	for (j = 0; j < feature->num_channels; j++) {
	/*
	* Disable all channels that are marked not to allow
	* IBSS operation or active scanning. In addition,
	* disable all channels that require radar detection,
	* since that (in addition to full DFS) is not yet
	* supported.
	*/
	if (feature->channels[j].flag &
	(HOSTAPD_CHAN_NO_IBSS \|
	HOSTAPD_CHAN_PASSIVE_SCAN \|
	HOSTAPD_CHAN_RADAR))
	feature->channels[j].flag \|=
	HOSTAPD_CHAN_DISABLED;
	if (feature->channels[j].flag & HOSTAPD_CHAN_DISABLED)
	continue;
	wpa_printf(MSG_MSGDUMP, "Allowed channel: mode=%d "
	"chan=%d freq=%d MHz max_tx_power=%d dBm",
	feature->mode,
	feature->channels[j].chan,
	feature->channels[j].freq,
	feature->channels[j].max_tx_power);
	}
	}

	return ret;
	}


	int hostapd_prepare_rates(struct hostapd_iface *iface,
	struct hostapd_hw_modes *mode)
	{
	int i, num_basic_rates = 0;
	int basic_rates_a[] = { 60, 120, 240, -1 };
	int basic_rates_b[] = { 10, 20, -1 };
	int basic_rates_g[] = { 10, 20, 55, 110, -1 };
	int *basic_rates;

	if (iface->conf->basic_rates)
	basic_rates = iface->conf->basic_rates;
	else switch (mode->mode) {
	case HOSTAPD_MODE_IEEE80211A:
	basic_rates = basic_rates_a;
	break;
	case HOSTAPD_MODE_IEEE80211B:
	basic_rates = basic_rates_b;
	break;
	case HOSTAPD_MODE_IEEE80211G:
	basic_rates = basic_rates_g;
	break;
	case HOSTAPD_MODE_IEEE80211AD:
	return 0; /* No basic rates for 11ad */
	default:
	return -1;
	}

	i = 0;
	while (basic_rates[i] >= 0)
	i++;
	if (i)
	i++; /* -1 termination */
	os_free(iface->basic_rates);
	iface->basic_rates = os_malloc(i * sizeof(int));
	if (iface->basic_rates)
	os_memcpy(iface->basic_rates, basic_rates, i * sizeof(int));

	os_free(iface->current_rates);
	iface->num_rates = 0;

	iface->current_rates =
	os_calloc(mode->num_rates, sizeof(struct hostapd_rate_data));
	if (!iface->current_rates) {
	wpa_printf(MSG_ERROR, "Failed to allocate memory for rate "
	"table.");
	return -1;
	}

	for (i = 0; i < mode->num_rates; i++) {
	struct hostapd_rate_data *rate;

	if (iface->conf->supported_rates &&
	!hostapd_rate_found(iface->conf->supported_rates,
	mode->rates[i]))
	continue;

	rate = &iface->current_rates[iface->num_rates];
	rate->rate = mode->rates[i];
	if (hostapd_rate_found(basic_rates, rate->rate)) {
	rate->flags \|= HOSTAPD_RATE_BASIC;
	num_basic_rates++;
	}
	wpa_printf(MSG_DEBUG, "RATE[%d] rate=%d flags=0x%x",
	iface->num_rates, rate->rate, rate->flags);
	iface->num_rates++;
	}

	if ((iface->num_rates == 0 \|\| num_basic_rates == 0) &&
	(!iface->conf->ieee80211n \|\| !iface->conf->require_ht)) {
	wpa_printf(MSG_ERROR, "No rates remaining in supported/basic "
	"rate sets (%d,%d).",
	iface->num_rates, num_basic_rates);
	return -1;
	}

	return 0;
	}


	#ifdef CONFIG_IEEE80211N
	static int ieee80211n_allowed_ht40_channel_pair(struct hostapd_iface *iface)
	{
	int sec_chan, ok, j, first;
	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
	184, 192 };
	size_t k;

	if (!iface->conf->secondary_channel)
	return 1; /* HT40 not used */

	sec_chan = iface->conf->channel + iface->conf->secondary_channel * 4;
	wpa_printf(MSG_DEBUG, "HT40: control channel: %d "
	"secondary channel: %d",
	iface->conf->channel, sec_chan);

	/* Verify that HT40 secondary channel is an allowed 20 MHz
	* channel */
	ok = 0;
	for (j = 0; j < iface->current_mode->num_channels; j++) {
	struct hostapd_channel_data *chan =
	&iface->current_mode->channels[j];
	if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
	chan->chan == sec_chan) {
	ok = 1;
	break;
	}
	}
	if (!ok) {
	wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
	sec_chan);
	return 0;
	}

	/*
	* Verify that HT40 primary,secondary channel pair is allowed per
	* IEEE 802.11n Annex J. This is only needed for 5 GHz band since
	* 2.4 GHz rules allow all cases where the secondary channel fits into
	* the list of allowed channels (already checked above).
	*/
	if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
	return 1;

	if (iface->conf->secondary_channel > 0)
	first = iface->conf->channel;
	else
	first = sec_chan;

	ok = 0;
	for (k = 0; k < sizeof(allowed) / sizeof(allowed[0]); k++) {
	if (first == allowed[k]) {
	ok = 1;
	break;
	}
	}
	if (!ok) {
	wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
	iface->conf->channel,
	iface->conf->secondary_channel);
	return 0;
	}

	return 1;
	}


	static void ieee80211n_switch_pri_sec(struct hostapd_iface *iface)
	{
	if (iface->conf->secondary_channel > 0) {
	iface->conf->channel += 4;
	iface->conf->secondary_channel = -1;
	} else {
	iface->conf->channel -= 4;
	iface->conf->secondary_channel = 1;
	}
	}


	static void ieee80211n_get_pri_sec_chan(struct wpa_scan_res *bss,
	int pri_chan, int sec_chan)
	{
	struct ieee80211_ht_operation *oper;
	struct ieee802_11_elems elems;

	pri_chan = sec_chan = 0;

	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
	if (elems.ht_operation &&
	elems.ht_operation_len >= sizeof(*oper)) {
	oper = (struct ieee80211_ht_operation *) elems.ht_operation;
	*pri_chan = oper->control_chan;
	if (oper->ht_param & HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH) {
	int sec = oper->ht_param &
	HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK;
	if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE)
	sec_chan = pri_chan + 4;
	else if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW)
	sec_chan = pri_chan - 4;
	}
	}
	}


	static int ieee80211n_check_40mhz_5g(struct hostapd_iface *iface,
	struct wpa_scan_results *scan_res)
	{
	int pri_chan, sec_chan, pri_freq, sec_freq, pri_bss, sec_bss;
	int bss_pri_chan, bss_sec_chan;
	size_t i;
	int match;

	pri_chan = iface->conf->channel;
	sec_chan = iface->conf->secondary_channel * 4;
	pri_freq = hostapd_hw_get_freq(iface->bss[0], pri_chan);
	if (iface->conf->secondary_channel > 0)
	sec_freq = pri_freq + 20;
	else
	sec_freq = pri_freq - 20;

	/*
	* Switch PRI/SEC channels if Beacons were detected on selected SEC
	* channel, but not on selected PRI channel.
	*/
	pri_bss = sec_bss = 0;
	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *bss = scan_res->res[i];
	if (bss->freq == pri_freq)
	pri_bss++;
	else if (bss->freq == sec_freq)
	sec_bss++;
	}
	if (sec_bss && !pri_bss) {
	wpa_printf(MSG_INFO, "Switch own primary and secondary "
	"channel to get secondary channel with no Beacons "
	"from other BSSes");
	ieee80211n_switch_pri_sec(iface);
	}

	/*
	* Match PRI/SEC channel with any existing HT40 BSS on the same
	* channels that we are about to use (if already mixed order in
	* existing BSSes, use own preference).
	*/
	match = 0;
	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *bss = scan_res->res[i];
	ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
	if (pri_chan == bss_pri_chan &&
	sec_chan == bss_sec_chan) {
	match = 1;
	break;
	}
	}
	if (!match) {
	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *bss = scan_res->res[i];
	ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan,
	&bss_sec_chan);
	if (pri_chan == bss_sec_chan &&
	sec_chan == bss_pri_chan) {
	wpa_printf(MSG_INFO, "Switch own primary and "
	"secondary channel due to BSS "
	"overlap with " MACSTR,
	MAC2STR(bss->bssid));
	ieee80211n_switch_pri_sec(iface);
	break;
	}
	}
	}

	return 1;
	}


	static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
	struct wpa_scan_results *scan_res)
	{
	int pri_freq, sec_freq;
	int affected_start, affected_end;
	size_t i;

	pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
	if (iface->conf->secondary_channel > 0)
	sec_freq = pri_freq + 20;
	else
	sec_freq = pri_freq - 20;
	affected_start = (pri_freq + sec_freq) / 2 - 25;
	affected_end = (pri_freq + sec_freq) / 2 + 25;
	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
	affected_start, affected_end);
	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *bss = scan_res->res[i];
	int pri = bss->freq;
	int sec = pri;
	int sec_chan, pri_chan;

	ieee80211n_get_pri_sec_chan(bss, &pri_chan, &sec_chan);

	if (sec_chan) {
	if (sec_chan < pri_chan)
	sec = pri - 20;
	else
	sec = pri + 20;
	}

	if ((pri < affected_start \|\| pri > affected_end) &&
	(sec < affected_start \|\| sec > affected_end))
	continue; /* not within affected channel range */

	wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
	" freq=%d pri=%d sec=%d",
	MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);

	if (sec_chan) {
	if (pri_freq != pri \|\| sec_freq != sec) {
	wpa_printf(MSG_DEBUG, "40 MHz pri/sec "
	"mismatch with BSS " MACSTR
	" <%d,%d> (chan=%d%c) vs. <%d,%d>",
	MAC2STR(bss->bssid),
	pri, sec, pri_chan,
	sec > pri ? '+' : '-',
	pri_freq, sec_freq);
	return 0;
	}
	}

	/* TODO: 40 MHz intolerant */
	}

	return 1;
	}


	static void ieee80211n_check_scan(struct hostapd_iface *iface)
	{
	struct wpa_scan_results *scan_res;
	int oper40;
	int res;

	/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
	* allowed per IEEE Std 802.11-2012, 10.15.3.2 */

	iface->scan_cb = NULL;

	scan_res = hostapd_driver_get_scan_results(iface->bss[0]);
	if (scan_res == NULL) {
	hostapd_setup_interface_complete(iface, 1);
	return;
	}

	if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A)
	oper40 = ieee80211n_check_40mhz_5g(iface, scan_res);
	else
	oper40 = ieee80211n_check_40mhz_2g4(iface, scan_res);
	wpa_scan_results_free(scan_res);

	if (!oper40) {
	wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
	"channel pri=%d sec=%d based on overlapping BSSes",
	iface->conf->channel,
	iface->conf->channel +
	iface->conf->secondary_channel * 4);
	iface->conf->secondary_channel = 0;
	iface->conf->ht_capab &= ~HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET;
	}

	res = ieee80211n_allowed_ht40_channel_pair(iface);
	hostapd_setup_interface_complete(iface, !res);
	}


	static void ieee80211n_scan_channels_2g4(struct hostapd_iface *iface,
	struct wpa_driver_scan_params *params)
	{
	/* Scan only the affected frequency range */
	int pri_freq, sec_freq;
	int affected_start, affected_end;
	int i, pos;
	struct hostapd_hw_modes *mode;

	if (iface->current_mode == NULL)
	return;

	pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
	if (iface->conf->secondary_channel > 0)
	sec_freq = pri_freq + 20;
	else
	sec_freq = pri_freq - 20;
	affected_start = (pri_freq + sec_freq) / 2 - 25;
	affected_end = (pri_freq + sec_freq) / 2 + 25;
	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
	affected_start, affected_end);

	mode = iface->current_mode;
	params->freqs = os_calloc(mode->num_channels + 1, sizeof(int));
	if (params->freqs == NULL)
	return;
	pos = 0;

	for (i = 0; i < mode->num_channels; i++) {
	struct hostapd_channel_data *chan = &mode->channels[i];
	if (chan->flag & HOSTAPD_CHAN_DISABLED)
	continue;
	if (chan->freq < affected_start \|\|
	chan->freq > affected_end)
	continue;
	params->freqs[pos++] = chan->freq;
	}
	}


	static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
	{
	struct wpa_driver_scan_params params;

	if (!iface->conf->secondary_channel)
	return 0; /* HT40 not used */

	wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling "
	"40 MHz channel");
	os_memset(&params, 0, sizeof(params));
	if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G)
	ieee80211n_scan_channels_2g4(iface, &params);
	if (hostapd_driver_scan(iface->bss[0], &params) < 0) {
	wpa_printf(MSG_ERROR, "Failed to request a scan of "
	"neighboring BSSes");
	os_free(params.freqs);
	return -1;
	}
	os_free(params.freqs);

	iface->scan_cb = ieee80211n_check_scan;
	return 1;
	}


	static int ieee80211n_supported_ht_capab(struct hostapd_iface *iface)
	{
	u16 hw = iface->current_mode->ht_capab;
	u16 conf = iface->conf->ht_capab;

	if ((conf & HT_CAP_INFO_LDPC_CODING_CAP) &&
	!(hw & HT_CAP_INFO_LDPC_CODING_CAP)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [LDPC]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) &&
	!(hw & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [HT40*]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_SMPS_MASK) != (hw & HT_CAP_INFO_SMPS_MASK) &&
	(conf & HT_CAP_INFO_SMPS_MASK) != HT_CAP_INFO_SMPS_DISABLED) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [SMPS-*]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_GREEN_FIELD) &&
	!(hw & HT_CAP_INFO_GREEN_FIELD)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [GF]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_SHORT_GI20MHZ) &&
	!(hw & HT_CAP_INFO_SHORT_GI20MHZ)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [SHORT-GI-20]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_SHORT_GI40MHZ) &&
	!(hw & HT_CAP_INFO_SHORT_GI40MHZ)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [SHORT-GI-40]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_TX_STBC) && !(hw & HT_CAP_INFO_TX_STBC)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [TX-STBC]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_RX_STBC_MASK) >
	(hw & HT_CAP_INFO_RX_STBC_MASK)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [RX-STBC*]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_DELAYED_BA) &&
	!(hw & HT_CAP_INFO_DELAYED_BA)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [DELAYED-BA]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_MAX_AMSDU_SIZE) &&
	!(hw & HT_CAP_INFO_MAX_AMSDU_SIZE)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [MAX-AMSDU-7935]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_DSSS_CCK40MHZ) &&
	!(hw & HT_CAP_INFO_DSSS_CCK40MHZ)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [DSSS_CCK-40]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_PSMP_SUPP) && !(hw & HT_CAP_INFO_PSMP_SUPP)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [PSMP]");
	return 0;
	}

	if ((conf & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT) &&
	!(hw & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT)) {
	wpa_printf(MSG_ERROR, "Driver does not support configured "
	"HT capability [LSIG-TXOP-PROT]");
	return 0;
	}

	return 1;
	}

	#endif /* CONFIG_IEEE80211N */


	int hostapd_check_ht_capab(struct hostapd_iface *iface)
	{
	#ifdef CONFIG_IEEE80211N
	int ret;
	if (!iface->conf->ieee80211n)
	return 0;
	if (!ieee80211n_supported_ht_capab(iface))
	return -1;
	ret = ieee80211n_check_40mhz(iface);
	if (ret)
	return ret;
	if (!ieee80211n_allowed_ht40_channel_pair(iface))
	return -1;
	#endif /* CONFIG_IEEE80211N */

	return 0;
	}


	/**
	* hostapd_select_hw_mode - Select the hardware mode
	* @iface: Pointer to interface data.
	* Returns: 0 on success, < 0 on failure
	*
	* Sets up the hardware mode, channel, rates, and passive scanning
	* based on the configuration.
	*/
	int hostapd_select_hw_mode(struct hostapd_iface *iface)
	{
	int i, j, ok;

	if (iface->num_hw_features < 1)
	return -1;

	iface->current_mode = NULL;
	for (i = 0; i < iface->num_hw_features; i++) {
	struct hostapd_hw_modes *mode = &iface->hw_features[i];
	if (mode->mode == iface->conf->hw_mode) {
	iface->current_mode = mode;
	break;
	}
	}

	if (iface->current_mode == NULL) {
	wpa_printf(MSG_ERROR, "Hardware does not support configured "
	"mode");
	hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
	HOSTAPD_LEVEL_WARNING,
	"Hardware does not support configured mode "
	"(%d) (hw_mode in hostapd.conf)",
	(int) iface->conf->hw_mode);
	return -2;
	}

	ok = 0;
	for (j = 0; j < iface->current_mode->num_channels; j++) {
	struct hostapd_channel_data *chan =
	&iface->current_mode->channels[j];
	if (chan->chan == iface->conf->channel) {
	if (chan->flag & HOSTAPD_CHAN_DISABLED) {
	wpa_printf(MSG_ERROR,
	"channel [%i] (%i) is disabled for "
	"use in AP mode, flags: 0x%x%s%s%s",
	j, chan->chan, chan->flag,
	chan->flag & HOSTAPD_CHAN_NO_IBSS ?
	" NO-IBSS" : "",
	chan->flag &
	HOSTAPD_CHAN_PASSIVE_SCAN ?
	" PASSIVE-SCAN" : "",
	chan->flag & HOSTAPD_CHAN_RADAR ?
	" RADAR" : "");
	} else {
	ok = 1;
	break;
	}
	}
	}
	if (ok && iface->conf->secondary_channel) {
	int sec_ok = 0;
	int sec_chan = iface->conf->channel +
	iface->conf->secondary_channel * 4;
	for (j = 0; j < iface->current_mode->num_channels; j++) {
	struct hostapd_channel_data *chan =
	&iface->current_mode->channels[j];
	if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
	(chan->chan == sec_chan)) {
	sec_ok = 1;
	break;
	}
	}
	if (!sec_ok) {
	hostapd_logger(iface->bss[0], NULL,
	HOSTAPD_MODULE_IEEE80211,
	HOSTAPD_LEVEL_WARNING,
	"Configured HT40 secondary channel "
	"(%d) not found from the channel list "
	"of current mode (%d) %s",
	sec_chan, iface->current_mode->mode,
	hostapd_hw_mode_txt(
	iface->current_mode->mode));
	ok = 0;
	}
	}
	if (iface->conf->channel == 0) {
	/* TODO: could request a scan of neighboring BSSes and select
	* the channel automatically */
	wpa_printf(MSG_ERROR, "Channel not configured "
	"(hw_mode/channel in hostapd.conf)");
	return -3;
	}
	if (ok == 0 && iface->conf->channel != 0) {
	hostapd_logger(iface->bss[0], NULL,
	HOSTAPD_MODULE_IEEE80211,
	HOSTAPD_LEVEL_WARNING,
	"Configured channel (%d) not found from the "
	"channel list of current mode (%d) %s",
	iface->conf->channel,
	iface->current_mode->mode,
	hostapd_hw_mode_txt(iface->current_mode->mode));
	iface->current_mode = NULL;
	}

	if (iface->current_mode == NULL) {
	hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
	HOSTAPD_LEVEL_WARNING,
	"Hardware does not support configured channel");
	return -4;
	}

	return 0;
	}


	const char * hostapd_hw_mode_txt(int mode)
	{
	switch (mode) {
	case HOSTAPD_MODE_IEEE80211A:
	return "IEEE 802.11a";
	case HOSTAPD_MODE_IEEE80211B:
	return "IEEE 802.11b";
	case HOSTAPD_MODE_IEEE80211G:
	return "IEEE 802.11g";
	case HOSTAPD_MODE_IEEE80211AD:
	return "IEEE 802.11ad";
	default:
	return "UNKNOWN";
	}
	}


	int hostapd_hw_get_freq(struct hostapd_data *hapd, int chan)
	{
	int i;

	if (!hapd->iface->current_mode)
	return 0;

	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
	struct hostapd_channel_data *ch =
	&hapd->iface->current_mode->channels[i];
	if (ch->chan == chan)
	return ch->freq;
	}

	return 0;
	}


	int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
	{
	int i;

	if (!hapd->iface->current_mode)
	return 0;

	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
	struct hostapd_channel_data *ch =
	&hapd->iface->current_mode->channels[i];
	if (ch->freq == freq)
	return ch->chan;
	}

	return 0;
	}

	int hostapd_hw_get_channel_flag(struct hostapd_data *hapd, int chan)
	{
	int i;

	if (!hapd->iface->current_mode)
	return 0;

	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
	struct hostapd_channel_data *ch =
	&hapd->iface->current_mode->channels[i];
	if (ch->chan == chan)
	return ch->flag;
	}

	return 0;
	}