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      1 /*
      2  * hostapd / Hardware feature query and different modes
      3  * Copyright 2002-2003, Instant802 Networks, Inc.
      4  * Copyright 2005-2006, Devicescape Software, Inc.
      5  * Copyright (c) 2008-2009, Jouni Malinen <j (at) w1.fi>
      6  *
      7  * This program is free software; you can redistribute it and/or modify
      8  * it under the terms of the GNU General Public License version 2 as
      9  * published by the Free Software Foundation.
     10  *
     11  * Alternatively, this software may be distributed under the terms of BSD
     12  * license.
     13  *
     14  * See README and COPYING for more details.
     15  */
     16 
     17 #include "utils/includes.h"
     18 
     19 #include "utils/common.h"
     20 #include "utils/eloop.h"
     21 #include "common/ieee802_11_defs.h"
     22 #include "common/ieee802_11_common.h"
     23 #include "drivers/driver.h"
     24 #include "hostapd.h"
     25 #include "ap_config.h"
     26 #include "ap_drv_ops.h"
     27 #include "hw_features.h"
     28 
     29 
     30 void hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
     31 			      size_t num_hw_features)
     32 {
     33 	size_t i;
     34 
     35 	if (hw_features == NULL)
     36 		return;
     37 
     38 	for (i = 0; i < num_hw_features; i++) {
     39 		os_free(hw_features[i].channels);
     40 		os_free(hw_features[i].rates);
     41 	}
     42 
     43 	os_free(hw_features);
     44 }
     45 
     46 
     47 int hostapd_get_hw_features(struct hostapd_iface *iface)
     48 {
     49 	struct hostapd_data *hapd = iface->bss[0];
     50 	int ret = 0, i, j;
     51 	u16 num_modes, flags;
     52 	struct hostapd_hw_modes *modes;
     53 
     54 	if (hostapd_drv_none(hapd))
     55 		return -1;
     56 	modes = hostapd_get_hw_feature_data(hapd, &num_modes, &flags);
     57 	if (modes == NULL) {
     58 		hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
     59 			       HOSTAPD_LEVEL_DEBUG,
     60 			       "Fetching hardware channel/rate support not "
     61 			       "supported.");
     62 		return -1;
     63 	}
     64 
     65 	iface->hw_flags = flags;
     66 
     67 	hostapd_free_hw_features(iface->hw_features, iface->num_hw_features);
     68 	iface->hw_features = modes;
     69 	iface->num_hw_features = num_modes;
     70 
     71 	for (i = 0; i < num_modes; i++) {
     72 		struct hostapd_hw_modes *feature = &modes[i];
     73 		/* set flag for channels we can use in current regulatory
     74 		 * domain */
     75 		for (j = 0; j < feature->num_channels; j++) {
     76 			/*
     77 			 * Disable all channels that are marked not to allow
     78 			 * IBSS operation or active scanning. In addition,
     79 			 * disable all channels that require radar detection,
     80 			 * since that (in addition to full DFS) is not yet
     81 			 * supported.
     82 			 */
     83 			if (feature->channels[j].flag &
     84 			    (HOSTAPD_CHAN_NO_IBSS |
     85 			     HOSTAPD_CHAN_PASSIVE_SCAN |
     86 			     HOSTAPD_CHAN_RADAR))
     87 				feature->channels[j].flag |=
     88 					HOSTAPD_CHAN_DISABLED;
     89 			if (feature->channels[j].flag & HOSTAPD_CHAN_DISABLED)
     90 				continue;
     91 			wpa_printf(MSG_MSGDUMP, "Allowed channel: mode=%d "
     92 				   "chan=%d freq=%d MHz max_tx_power=%d dBm",
     93 				   feature->mode,
     94 				   feature->channels[j].chan,
     95 				   feature->channels[j].freq,
     96 				   feature->channels[j].max_tx_power);
     97 		}
     98 	}
     99 
    100 	return ret;
    101 }
    102 
    103 
    104 int hostapd_prepare_rates(struct hostapd_data *hapd,
    105 			  struct hostapd_hw_modes *mode)
    106 {
    107 	int i, num_basic_rates = 0;
    108 	int basic_rates_a[] = { 60, 120, 240, -1 };
    109 	int basic_rates_b[] = { 10, 20, -1 };
    110 	int basic_rates_g[] = { 10, 20, 55, 110, -1 };
    111 	int *basic_rates;
    112 
    113 	if (hapd->iconf->basic_rates)
    114 		basic_rates = hapd->iconf->basic_rates;
    115 	else switch (mode->mode) {
    116 	case HOSTAPD_MODE_IEEE80211A:
    117 		basic_rates = basic_rates_a;
    118 		break;
    119 	case HOSTAPD_MODE_IEEE80211B:
    120 		basic_rates = basic_rates_b;
    121 		break;
    122 	case HOSTAPD_MODE_IEEE80211G:
    123 		basic_rates = basic_rates_g;
    124 		break;
    125 	default:
    126 		return -1;
    127 	}
    128 
    129 	if (hostapd_set_rate_sets(hapd, hapd->iconf->supported_rates,
    130 				  basic_rates, mode->mode)) {
    131 		wpa_printf(MSG_ERROR, "Failed to update rate sets in kernel "
    132 			   "module");
    133 	}
    134 
    135 	os_free(hapd->iface->current_rates);
    136 	hapd->iface->num_rates = 0;
    137 
    138 	hapd->iface->current_rates =
    139 		os_zalloc(mode->num_rates * sizeof(struct hostapd_rate_data));
    140 	if (!hapd->iface->current_rates) {
    141 		wpa_printf(MSG_ERROR, "Failed to allocate memory for rate "
    142 			   "table.");
    143 		return -1;
    144 	}
    145 
    146 	for (i = 0; i < mode->num_rates; i++) {
    147 		struct hostapd_rate_data *rate;
    148 
    149 		if (hapd->iconf->supported_rates &&
    150 		    !hostapd_rate_found(hapd->iconf->supported_rates,
    151 					mode->rates[i]))
    152 			continue;
    153 
    154 		rate = &hapd->iface->current_rates[hapd->iface->num_rates];
    155 		rate->rate = mode->rates[i];
    156 		if (hostapd_rate_found(basic_rates, rate->rate)) {
    157 			rate->flags |= HOSTAPD_RATE_BASIC;
    158 			num_basic_rates++;
    159 		}
    160 		wpa_printf(MSG_DEBUG, "RATE[%d] rate=%d flags=0x%x",
    161 			   hapd->iface->num_rates, rate->rate, rate->flags);
    162 		hapd->iface->num_rates++;
    163 	}
    164 
    165 	if ((hapd->iface->num_rates == 0 || num_basic_rates == 0) &&
    166 	    (!hapd->iconf->ieee80211n || !hapd->iconf->require_ht)) {
    167 		wpa_printf(MSG_ERROR, "No rates remaining in supported/basic "
    168 			   "rate sets (%d,%d).",
    169 			   hapd->iface->num_rates, num_basic_rates);
    170 		return -1;
    171 	}
    172 
    173 	return 0;
    174 }
    175 
    176 
    177 #ifdef CONFIG_IEEE80211N
    178 static int ieee80211n_allowed_ht40_channel_pair(struct hostapd_iface *iface)
    179 {
    180 	int sec_chan, ok, j, first;
    181 	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
    182 			  184, 192 };
    183 	size_t k;
    184 
    185 	if (!iface->conf->secondary_channel)
    186 		return 1; /* HT40 not used */
    187 
    188 	sec_chan = iface->conf->channel + iface->conf->secondary_channel * 4;
    189 	wpa_printf(MSG_DEBUG, "HT40: control channel: %d  "
    190 		   "secondary channel: %d",
    191 		   iface->conf->channel, sec_chan);
    192 
    193 	/* Verify that HT40 secondary channel is an allowed 20 MHz
    194 	 * channel */
    195 	ok = 0;
    196 	for (j = 0; j < iface->current_mode->num_channels; j++) {
    197 		struct hostapd_channel_data *chan =
    198 			&iface->current_mode->channels[j];
    199 		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
    200 		    chan->chan == sec_chan) {
    201 			ok = 1;
    202 			break;
    203 		}
    204 	}
    205 	if (!ok) {
    206 		wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
    207 			   sec_chan);
    208 		return 0;
    209 	}
    210 
    211 	/*
    212 	 * Verify that HT40 primary,secondary channel pair is allowed per
    213 	 * IEEE 802.11n Annex J. This is only needed for 5 GHz band since
    214 	 * 2.4 GHz rules allow all cases where the secondary channel fits into
    215 	 * the list of allowed channels (already checked above).
    216 	 */
    217 	if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
    218 		return 1;
    219 
    220 	if (iface->conf->secondary_channel > 0)
    221 		first = iface->conf->channel;
    222 	else
    223 		first = sec_chan;
    224 
    225 	ok = 0;
    226 	for (k = 0; k < sizeof(allowed) / sizeof(allowed[0]); k++) {
    227 		if (first == allowed[k]) {
    228 			ok = 1;
    229 			break;
    230 		}
    231 	}
    232 	if (!ok) {
    233 		wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
    234 			   iface->conf->channel,
    235 			   iface->conf->secondary_channel);
    236 		return 0;
    237 	}
    238 
    239 	return 1;
    240 }
    241 
    242 
    243 static void ieee80211n_switch_pri_sec(struct hostapd_iface *iface)
    244 {
    245 	if (iface->conf->secondary_channel > 0) {
    246 		iface->conf->channel += 4;
    247 		iface->conf->secondary_channel = -1;
    248 	} else {
    249 		iface->conf->channel -= 4;
    250 		iface->conf->secondary_channel = 1;
    251 	}
    252 }
    253 
    254 
    255 static void ieee80211n_get_pri_sec_chan(struct wpa_scan_res *bss,
    256 					int *pri_chan, int *sec_chan)
    257 {
    258 	struct ieee80211_ht_operation *oper;
    259 	struct ieee802_11_elems elems;
    260 
    261 	*pri_chan = *sec_chan = 0;
    262 
    263 	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
    264 	if (elems.ht_operation &&
    265 	    elems.ht_operation_len >= sizeof(*oper)) {
    266 		oper = (struct ieee80211_ht_operation *) elems.ht_operation;
    267 		*pri_chan = oper->control_chan;
    268 		if (oper->ht_param & HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH) {
    269 			int sec = oper->ht_param &
    270 				HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK;
    271 			if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE)
    272 				*sec_chan = *pri_chan + 4;
    273 			else if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW)
    274 				*sec_chan = *pri_chan - 4;
    275 		}
    276 	}
    277 }
    278 
    279 
    280 static int ieee80211n_check_40mhz_5g(struct hostapd_iface *iface,
    281 				     struct wpa_scan_results *scan_res)
    282 {
    283 	int pri_chan, sec_chan, pri_freq, sec_freq, pri_bss, sec_bss;
    284 	int bss_pri_chan, bss_sec_chan;
    285 	size_t i;
    286 	int match;
    287 
    288 	pri_chan = iface->conf->channel;
    289 	sec_chan = iface->conf->secondary_channel * 4;
    290 	pri_freq = hostapd_hw_get_freq(iface->bss[0], pri_chan);
    291 	if (iface->conf->secondary_channel > 0)
    292 		sec_freq = pri_freq + 20;
    293 	else
    294 		sec_freq = pri_freq - 20;
    295 
    296 	/*
    297 	 * Switch PRI/SEC channels if Beacons were detected on selected SEC
    298 	 * channel, but not on selected PRI channel.
    299 	 */
    300 	pri_bss = sec_bss = 0;
    301 	for (i = 0; i < scan_res->num; i++) {
    302 		struct wpa_scan_res *bss = scan_res->res[i];
    303 		if (bss->freq == pri_freq)
    304 			pri_bss++;
    305 		else if (bss->freq == sec_freq)
    306 			sec_bss++;
    307 	}
    308 	if (sec_bss && !pri_bss) {
    309 		wpa_printf(MSG_INFO, "Switch own primary and secondary "
    310 			   "channel to get secondary channel with no Beacons "
    311 			   "from other BSSes");
    312 		ieee80211n_switch_pri_sec(iface);
    313 	}
    314 
    315 	/*
    316 	 * Match PRI/SEC channel with any existing HT40 BSS on the same
    317 	 * channels that we are about to use (if already mixed order in
    318 	 * existing BSSes, use own preference).
    319 	 */
    320 	match = 0;
    321 	for (i = 0; i < scan_res->num; i++) {
    322 		struct wpa_scan_res *bss = scan_res->res[i];
    323 		ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
    324 		if (pri_chan == bss_pri_chan &&
    325 		    sec_chan == bss_sec_chan) {
    326 			match = 1;
    327 			break;
    328 		}
    329 	}
    330 	if (!match) {
    331 		for (i = 0; i < scan_res->num; i++) {
    332 			struct wpa_scan_res *bss = scan_res->res[i];
    333 			ieee80211n_get_pri_sec_chan(bss, &bss_pri_chan,
    334 						    &bss_sec_chan);
    335 			if (pri_chan == bss_sec_chan &&
    336 			    sec_chan == bss_pri_chan) {
    337 				wpa_printf(MSG_INFO, "Switch own primary and "
    338 					   "secondary channel due to BSS "
    339 					   "overlap with " MACSTR,
    340 					   MAC2STR(bss->bssid));
    341 				ieee80211n_switch_pri_sec(iface);
    342 				break;
    343 			}
    344 		}
    345 	}
    346 
    347 	return 1;
    348 }
    349 
    350 
    351 static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface,
    352 				      struct wpa_scan_results *scan_res)
    353 {
    354 	int pri_freq, sec_freq;
    355 	int affected_start, affected_end;
    356 	size_t i;
    357 
    358 	pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
    359 	if (iface->conf->secondary_channel > 0)
    360 		sec_freq = pri_freq + 20;
    361 	else
    362 		sec_freq = pri_freq - 20;
    363 	affected_start = (pri_freq + sec_freq) / 2 - 25;
    364 	affected_end = (pri_freq + sec_freq) / 2 + 25;
    365 	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
    366 		   affected_start, affected_end);
    367 	for (i = 0; i < scan_res->num; i++) {
    368 		struct wpa_scan_res *bss = scan_res->res[i];
    369 		int pri = bss->freq;
    370 		int sec = pri;
    371 		int sec_chan, pri_chan;
    372 
    373 		ieee80211n_get_pri_sec_chan(bss, &pri_chan, &sec_chan);
    374 
    375 		if (sec_chan) {
    376 			if (sec_chan < pri_chan)
    377 				sec = pri - 20;
    378 			else
    379 				sec = pri + 20;
    380 		}
    381 
    382 		if ((pri < affected_start || pri > affected_end) &&
    383 		    (sec < affected_start || sec > affected_end))
    384 			continue; /* not within affected channel range */
    385 
    386 		wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
    387 			   " freq=%d pri=%d sec=%d",
    388 			   MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);
    389 
    390 		if (sec_chan) {
    391 			if (pri_freq != pri || sec_freq != sec) {
    392 				wpa_printf(MSG_DEBUG, "40 MHz pri/sec "
    393 					   "mismatch with BSS " MACSTR
    394 					   " <%d,%d> (chan=%d%c) vs. <%d,%d>",
    395 					   MAC2STR(bss->bssid),
    396 					   pri, sec, pri_chan,
    397 					   sec > pri ? '+' : '-',
    398 					   pri_freq, sec_freq);
    399 				return 0;
    400 			}
    401 		}
    402 
    403 		/* TODO: 40 MHz intolerant */
    404 	}
    405 
    406 	return 1;
    407 }
    408 
    409 
    410 static void wpa_scan_results_free(struct wpa_scan_results *res)
    411 {
    412 	size_t i;
    413 
    414 	if (res == NULL)
    415 		return;
    416 
    417 	for (i = 0; i < res->num; i++)
    418 		os_free(res->res[i]);
    419 	os_free(res->res);
    420 	os_free(res);
    421 }
    422 
    423 
    424 static void ieee80211n_check_scan(struct hostapd_iface *iface)
    425 {
    426 	struct wpa_scan_results *scan_res;
    427 	int oper40;
    428 	int res;
    429 
    430 	/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
    431 	 * allowed per IEEE 802.11n/D7.0, 11.14.3.2 */
    432 
    433 	iface->scan_cb = NULL;
    434 
    435 	scan_res = hostapd_driver_get_scan_results(iface->bss[0]);
    436 	if (scan_res == NULL) {
    437 		hostapd_setup_interface_complete(iface, 1);
    438 		return;
    439 	}
    440 
    441 	if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A)
    442 		oper40 = ieee80211n_check_40mhz_5g(iface, scan_res);
    443 	else
    444 		oper40 = ieee80211n_check_40mhz_2g4(iface, scan_res);
    445 	wpa_scan_results_free(scan_res);
    446 
    447 	if (!oper40) {
    448 		wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
    449 			   "channel pri=%d sec=%d based on overlapping BSSes",
    450 			   iface->conf->channel,
    451 			   iface->conf->channel +
    452 			   iface->conf->secondary_channel * 4);
    453 		iface->conf->secondary_channel = 0;
    454 		iface->conf->ht_capab &= ~HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET;
    455 	}
    456 
    457 	res = ieee80211n_allowed_ht40_channel_pair(iface);
    458 	hostapd_setup_interface_complete(iface, !res);
    459 }
    460 
    461 
    462 static int ieee80211n_check_40mhz(struct hostapd_iface *iface)
    463 {
    464 	struct wpa_driver_scan_params params;
    465 
    466 	if (!iface->conf->secondary_channel)
    467 		return 0; /* HT40 not used */
    468 
    469 	wpa_printf(MSG_DEBUG, "Scan for neighboring BSSes prior to enabling "
    470 		   "40 MHz channel");
    471 	os_memset(&params, 0, sizeof(params));
    472 	/* TODO: scan only the needed frequency */
    473 	if (hostapd_driver_scan(iface->bss[0], &params) < 0) {
    474 		wpa_printf(MSG_ERROR, "Failed to request a scan of "
    475 			   "neighboring BSSes");
    476 		return -1;
    477 	}
    478 
    479 	iface->scan_cb = ieee80211n_check_scan;
    480 	return 1;
    481 }
    482 
    483 
    484 static int ieee80211n_supported_ht_capab(struct hostapd_iface *iface)
    485 {
    486 	u16 hw = iface->current_mode->ht_capab;
    487 	u16 conf = iface->conf->ht_capab;
    488 
    489 	if ((conf & HT_CAP_INFO_LDPC_CODING_CAP) &&
    490 	    !(hw & HT_CAP_INFO_LDPC_CODING_CAP)) {
    491 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    492 			   "HT capability [LDPC]");
    493 		return 0;
    494 	}
    495 
    496 	if ((conf & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) &&
    497 	    !(hw & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)) {
    498 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    499 			   "HT capability [HT40*]");
    500 		return 0;
    501 	}
    502 
    503 	if ((conf & HT_CAP_INFO_SMPS_MASK) != (hw & HT_CAP_INFO_SMPS_MASK) &&
    504 	    (conf & HT_CAP_INFO_SMPS_MASK) != HT_CAP_INFO_SMPS_DISABLED) {
    505 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    506 			   "HT capability [SMPS-*]");
    507 		return 0;
    508 	}
    509 
    510 	if ((conf & HT_CAP_INFO_GREEN_FIELD) &&
    511 	    !(hw & HT_CAP_INFO_GREEN_FIELD)) {
    512 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    513 			   "HT capability [GF]");
    514 		return 0;
    515 	}
    516 
    517 	if ((conf & HT_CAP_INFO_SHORT_GI20MHZ) &&
    518 	    !(hw & HT_CAP_INFO_SHORT_GI20MHZ)) {
    519 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    520 			   "HT capability [SHORT-GI-20]");
    521 		return 0;
    522 	}
    523 
    524 	if ((conf & HT_CAP_INFO_SHORT_GI40MHZ) &&
    525 	    !(hw & HT_CAP_INFO_SHORT_GI40MHZ)) {
    526 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    527 			   "HT capability [SHORT-GI-40]");
    528 		return 0;
    529 	}
    530 
    531 	if ((conf & HT_CAP_INFO_TX_STBC) && !(hw & HT_CAP_INFO_TX_STBC)) {
    532 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    533 			   "HT capability [TX-STBC]");
    534 		return 0;
    535 	}
    536 
    537 	if ((conf & HT_CAP_INFO_RX_STBC_MASK) >
    538 	    (hw & HT_CAP_INFO_RX_STBC_MASK)) {
    539 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    540 			   "HT capability [RX-STBC*]");
    541 		return 0;
    542 	}
    543 
    544 	if ((conf & HT_CAP_INFO_DELAYED_BA) &&
    545 	    !(hw & HT_CAP_INFO_DELAYED_BA)) {
    546 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    547 			   "HT capability [DELAYED-BA]");
    548 		return 0;
    549 	}
    550 
    551 	if ((conf & HT_CAP_INFO_MAX_AMSDU_SIZE) &&
    552 	    !(hw & HT_CAP_INFO_MAX_AMSDU_SIZE)) {
    553 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    554 			   "HT capability [MAX-AMSDU-7935]");
    555 		return 0;
    556 	}
    557 
    558 	if ((conf & HT_CAP_INFO_DSSS_CCK40MHZ) &&
    559 	    !(hw & HT_CAP_INFO_DSSS_CCK40MHZ)) {
    560 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    561 			   "HT capability [DSSS_CCK-40]");
    562 		return 0;
    563 	}
    564 
    565 	if ((conf & HT_CAP_INFO_PSMP_SUPP) && !(hw & HT_CAP_INFO_PSMP_SUPP)) {
    566 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    567 			   "HT capability [PSMP]");
    568 		return 0;
    569 	}
    570 
    571 	if ((conf & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT) &&
    572 	    !(hw & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT)) {
    573 		wpa_printf(MSG_ERROR, "Driver does not support configured "
    574 			   "HT capability [LSIG-TXOP-PROT]");
    575 		return 0;
    576 	}
    577 
    578 	return 1;
    579 }
    580 
    581 #endif /* CONFIG_IEEE80211N */
    582 
    583 
    584 int hostapd_check_ht_capab(struct hostapd_iface *iface)
    585 {
    586 #ifdef CONFIG_IEEE80211N
    587 	int ret;
    588 	if (!iface->conf->ieee80211n)
    589 		return 0;
    590 	if (!ieee80211n_supported_ht_capab(iface))
    591 		return -1;
    592 	ret = ieee80211n_check_40mhz(iface);
    593 	if (ret)
    594 		return ret;
    595 	if (!ieee80211n_allowed_ht40_channel_pair(iface))
    596 		return -1;
    597 #endif /* CONFIG_IEEE80211N */
    598 
    599 	return 0;
    600 }
    601 
    602 
    603 /**
    604  * hostapd_select_hw_mode - Select the hardware mode
    605  * @iface: Pointer to interface data.
    606  * Returns: 0 on success, < 0 on failure
    607  *
    608  * Sets up the hardware mode, channel, rates, and passive scanning
    609  * based on the configuration.
    610  */
    611 int hostapd_select_hw_mode(struct hostapd_iface *iface)
    612 {
    613 	int i, j, ok;
    614 
    615 	if (iface->num_hw_features < 1)
    616 		return -1;
    617 
    618 	iface->current_mode = NULL;
    619 	for (i = 0; i < iface->num_hw_features; i++) {
    620 		struct hostapd_hw_modes *mode = &iface->hw_features[i];
    621 		if (mode->mode == iface->conf->hw_mode) {
    622 			iface->current_mode = mode;
    623 			break;
    624 		}
    625 	}
    626 
    627 	if (iface->current_mode == NULL) {
    628 		wpa_printf(MSG_ERROR, "Hardware does not support configured "
    629 			   "mode");
    630 		hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
    631 			       HOSTAPD_LEVEL_WARNING,
    632 			       "Hardware does not support configured mode "
    633 			       "(%d)", (int) iface->conf->hw_mode);
    634 		return -2;
    635 	}
    636 
    637 	ok = 0;
    638 	for (j = 0; j < iface->current_mode->num_channels; j++) {
    639 		struct hostapd_channel_data *chan =
    640 			&iface->current_mode->channels[j];
    641 		if (chan->chan == iface->conf->channel) {
    642 			if (chan->flag & HOSTAPD_CHAN_DISABLED) {
    643 				wpa_printf(MSG_ERROR,
    644 					   "channel [%i] (%i) is disabled for "
    645 					   "use in AP mode, flags: 0x%x",
    646 					   j, chan->chan, chan->flag);
    647 			} else {
    648 				ok = 1;
    649 				break;
    650 			}
    651 		}
    652 	}
    653 	if (ok && iface->conf->secondary_channel) {
    654 		int sec_ok = 0;
    655 		int sec_chan = iface->conf->channel +
    656 			iface->conf->secondary_channel * 4;
    657 		for (j = 0; j < iface->current_mode->num_channels; j++) {
    658 			struct hostapd_channel_data *chan =
    659 				&iface->current_mode->channels[j];
    660 			if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
    661 			    (chan->chan == sec_chan)) {
    662 				sec_ok = 1;
    663 				break;
    664 			}
    665 		}
    666 		if (!sec_ok) {
    667 			hostapd_logger(iface->bss[0], NULL,
    668 				       HOSTAPD_MODULE_IEEE80211,
    669 				       HOSTAPD_LEVEL_WARNING,
    670 				       "Configured HT40 secondary channel "
    671 				       "(%d) not found from the channel list "
    672 				       "of current mode (%d) %s",
    673 				       sec_chan, iface->current_mode->mode,
    674 				       hostapd_hw_mode_txt(
    675 					       iface->current_mode->mode));
    676 			ok = 0;
    677 		}
    678 	}
    679 	if (iface->conf->channel == 0) {
    680 		/* TODO: could request a scan of neighboring BSSes and select
    681 		 * the channel automatically */
    682 		wpa_printf(MSG_ERROR, "Channel not configured "
    683 			   "(hw_mode/channel in hostapd.conf)");
    684 		return -3;
    685 	}
    686 	if (ok == 0 && iface->conf->channel != 0) {
    687 		hostapd_logger(iface->bss[0], NULL,
    688 			       HOSTAPD_MODULE_IEEE80211,
    689 			       HOSTAPD_LEVEL_WARNING,
    690 			       "Configured channel (%d) not found from the "
    691 			       "channel list of current mode (%d) %s",
    692 			       iface->conf->channel,
    693 			       iface->current_mode->mode,
    694 			       hostapd_hw_mode_txt(iface->current_mode->mode));
    695 		iface->current_mode = NULL;
    696 	}
    697 
    698 	if (iface->current_mode == NULL) {
    699 		hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
    700 			       HOSTAPD_LEVEL_WARNING,
    701 			       "Hardware does not support configured channel");
    702 		return -4;
    703 	}
    704 
    705 	return 0;
    706 }
    707 
    708 
    709 const char * hostapd_hw_mode_txt(int mode)
    710 {
    711 	switch (mode) {
    712 	case HOSTAPD_MODE_IEEE80211A:
    713 		return "IEEE 802.11a";
    714 	case HOSTAPD_MODE_IEEE80211B:
    715 		return "IEEE 802.11b";
    716 	case HOSTAPD_MODE_IEEE80211G:
    717 		return "IEEE 802.11g";
    718 	default:
    719 		return "UNKNOWN";
    720 	}
    721 }
    722 
    723 
    724 int hostapd_hw_get_freq(struct hostapd_data *hapd, int chan)
    725 {
    726 	int i;
    727 
    728 	if (!hapd->iface->current_mode)
    729 		return 0;
    730 
    731 	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
    732 		struct hostapd_channel_data *ch =
    733 			&hapd->iface->current_mode->channels[i];
    734 		if (ch->chan == chan)
    735 			return ch->freq;
    736 	}
    737 
    738 	return 0;
    739 }
    740 
    741 
    742 int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
    743 {
    744 	int i;
    745 
    746 	if (!hapd->iface->current_mode)
    747 		return 0;
    748 
    749 	for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
    750 		struct hostapd_channel_data *ch =
    751 			&hapd->iface->current_mode->channels[i];
    752 		if (ch->freq == freq)
    753 			return ch->chan;
    754 	}
    755 
    756 	return 0;
    757 }
    758