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      1 /*
      2  * Common hostapd/wpa_supplicant HW features
      3  * Copyright (c) 2002-2013, Jouni Malinen <j (at) w1.fi>
      4  * Copyright (c) 2015, Qualcomm Atheros, Inc.
      5  *
      6  * This software may be distributed under the terms of the BSD license.
      7  * See README for more details.
      8  */
      9 
     10 #include "includes.h"
     11 
     12 #include "common.h"
     13 #include "defs.h"
     14 #include "ieee802_11_defs.h"
     15 #include "ieee802_11_common.h"
     16 #include "hw_features_common.h"
     17 
     18 
     19 struct hostapd_channel_data * hw_get_channel_chan(struct hostapd_hw_modes *mode,
     20 						  int chan, int *freq)
     21 {
     22 	int i;
     23 
     24 	if (freq)
     25 		*freq = 0;
     26 
     27 	if (!mode)
     28 		return NULL;
     29 
     30 	for (i = 0; i < mode->num_channels; i++) {
     31 		struct hostapd_channel_data *ch = &mode->channels[i];
     32 		if (ch->chan == chan) {
     33 			if (freq)
     34 				*freq = ch->freq;
     35 			return ch;
     36 		}
     37 	}
     38 
     39 	return NULL;
     40 }
     41 
     42 
     43 struct hostapd_channel_data * hw_get_channel_freq(struct hostapd_hw_modes *mode,
     44 						  int freq, int *chan)
     45 {
     46 	int i;
     47 
     48 	if (chan)
     49 		*chan = 0;
     50 
     51 	if (!mode)
     52 		return NULL;
     53 
     54 	for (i = 0; i < mode->num_channels; i++) {
     55 		struct hostapd_channel_data *ch = &mode->channels[i];
     56 		if (ch->freq == freq) {
     57 			if (chan)
     58 				*chan = ch->chan;
     59 			return ch;
     60 		}
     61 	}
     62 
     63 	return NULL;
     64 }
     65 
     66 
     67 int hw_get_freq(struct hostapd_hw_modes *mode, int chan)
     68 {
     69 	int freq;
     70 
     71 	hw_get_channel_chan(mode, chan, &freq);
     72 
     73 	return freq;
     74 }
     75 
     76 
     77 int hw_get_chan(struct hostapd_hw_modes *mode, int freq)
     78 {
     79 	int chan;
     80 
     81 	hw_get_channel_freq(mode, freq, &chan);
     82 
     83 	return chan;
     84 }
     85 
     86 
     87 int allowed_ht40_channel_pair(struct hostapd_hw_modes *mode, int pri_chan,
     88 			      int sec_chan)
     89 {
     90 	int ok, j, first;
     91 	int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 140,
     92 			  149, 157, 184, 192 };
     93 	size_t k;
     94 
     95 	if (pri_chan == sec_chan || !sec_chan)
     96 		return 1; /* HT40 not used */
     97 
     98 	wpa_printf(MSG_DEBUG,
     99 		   "HT40: control channel: %d  secondary channel: %d",
    100 		   pri_chan, sec_chan);
    101 
    102 	/* Verify that HT40 secondary channel is an allowed 20 MHz
    103 	 * channel */
    104 	ok = 0;
    105 	for (j = 0; j < mode->num_channels; j++) {
    106 		struct hostapd_channel_data *chan = &mode->channels[j];
    107 		if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
    108 		    chan->chan == sec_chan) {
    109 			ok = 1;
    110 			break;
    111 		}
    112 	}
    113 	if (!ok) {
    114 		wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
    115 			   sec_chan);
    116 		return 0;
    117 	}
    118 
    119 	/*
    120 	 * Verify that HT40 primary,secondary channel pair is allowed per
    121 	 * IEEE 802.11n Annex J. This is only needed for 5 GHz band since
    122 	 * 2.4 GHz rules allow all cases where the secondary channel fits into
    123 	 * the list of allowed channels (already checked above).
    124 	 */
    125 	if (mode->mode != HOSTAPD_MODE_IEEE80211A)
    126 		return 1;
    127 
    128 	first = pri_chan < sec_chan ? pri_chan : sec_chan;
    129 
    130 	ok = 0;
    131 	for (k = 0; k < ARRAY_SIZE(allowed); k++) {
    132 		if (first == allowed[k]) {
    133 			ok = 1;
    134 			break;
    135 		}
    136 	}
    137 	if (!ok) {
    138 		wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
    139 			   pri_chan, sec_chan);
    140 		return 0;
    141 	}
    142 
    143 	return 1;
    144 }
    145 
    146 
    147 void get_pri_sec_chan(struct wpa_scan_res *bss, int *pri_chan, int *sec_chan)
    148 {
    149 	struct ieee80211_ht_operation *oper;
    150 	struct ieee802_11_elems elems;
    151 
    152 	*pri_chan = *sec_chan = 0;
    153 
    154 	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
    155 	if (elems.ht_operation) {
    156 		oper = (struct ieee80211_ht_operation *) elems.ht_operation;
    157 		*pri_chan = oper->primary_chan;
    158 		if (oper->ht_param & HT_INFO_HT_PARAM_STA_CHNL_WIDTH) {
    159 			int sec = oper->ht_param &
    160 				HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK;
    161 			if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_ABOVE)
    162 				*sec_chan = *pri_chan + 4;
    163 			else if (sec == HT_INFO_HT_PARAM_SECONDARY_CHNL_BELOW)
    164 				*sec_chan = *pri_chan - 4;
    165 		}
    166 	}
    167 }
    168 
    169 
    170 int check_40mhz_5g(struct hostapd_hw_modes *mode,
    171 		   struct wpa_scan_results *scan_res, int pri_chan,
    172 		   int sec_chan)
    173 {
    174 	int pri_freq, sec_freq, pri_bss, sec_bss;
    175 	int bss_pri_chan, bss_sec_chan;
    176 	size_t i;
    177 	int match;
    178 
    179 	if (!mode || !scan_res || !pri_chan || !sec_chan ||
    180 	    pri_chan == sec_chan)
    181 		return 0;
    182 
    183 	pri_freq = hw_get_freq(mode, pri_chan);
    184 	sec_freq = hw_get_freq(mode, sec_chan);
    185 
    186 	/*
    187 	 * Switch PRI/SEC channels if Beacons were detected on selected SEC
    188 	 * channel, but not on selected PRI channel.
    189 	 */
    190 	pri_bss = sec_bss = 0;
    191 	for (i = 0; i < scan_res->num; i++) {
    192 		struct wpa_scan_res *bss = scan_res->res[i];
    193 		if (bss->freq == pri_freq)
    194 			pri_bss++;
    195 		else if (bss->freq == sec_freq)
    196 			sec_bss++;
    197 	}
    198 	if (sec_bss && !pri_bss) {
    199 		wpa_printf(MSG_INFO,
    200 			   "Switch own primary and secondary channel to get secondary channel with no Beacons from other BSSes");
    201 		return 2;
    202 	}
    203 
    204 	/*
    205 	 * Match PRI/SEC channel with any existing HT40 BSS on the same
    206 	 * channels that we are about to use (if already mixed order in
    207 	 * existing BSSes, use own preference).
    208 	 */
    209 	match = 0;
    210 	for (i = 0; i < scan_res->num; i++) {
    211 		struct wpa_scan_res *bss = scan_res->res[i];
    212 		get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
    213 		if (pri_chan == bss_pri_chan &&
    214 		    sec_chan == bss_sec_chan) {
    215 			match = 1;
    216 			break;
    217 		}
    218 	}
    219 	if (!match) {
    220 		for (i = 0; i < scan_res->num; i++) {
    221 			struct wpa_scan_res *bss = scan_res->res[i];
    222 			get_pri_sec_chan(bss, &bss_pri_chan, &bss_sec_chan);
    223 			if (pri_chan == bss_sec_chan &&
    224 			    sec_chan == bss_pri_chan) {
    225 				wpa_printf(MSG_INFO, "Switch own primary and "
    226 					   "secondary channel due to BSS "
    227 					   "overlap with " MACSTR,
    228 					   MAC2STR(bss->bssid));
    229 				return 2;
    230 			}
    231 		}
    232 	}
    233 
    234 	return 1;
    235 }
    236 
    237 
    238 static int check_20mhz_bss(struct wpa_scan_res *bss, int pri_freq, int start,
    239 			   int end)
    240 {
    241 	struct ieee802_11_elems elems;
    242 	struct ieee80211_ht_operation *oper;
    243 
    244 	if (bss->freq < start || bss->freq > end || bss->freq == pri_freq)
    245 		return 0;
    246 
    247 	ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems, 0);
    248 	if (!elems.ht_capabilities) {
    249 		wpa_printf(MSG_DEBUG, "Found overlapping legacy BSS: "
    250 			   MACSTR " freq=%d", MAC2STR(bss->bssid), bss->freq);
    251 		return 1;
    252 	}
    253 
    254 	if (elems.ht_operation) {
    255 		oper = (struct ieee80211_ht_operation *) elems.ht_operation;
    256 		if (oper->ht_param & HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK)
    257 			return 0;
    258 
    259 		wpa_printf(MSG_DEBUG, "Found overlapping 20 MHz HT BSS: "
    260 			   MACSTR " freq=%d", MAC2STR(bss->bssid), bss->freq);
    261 		return 1;
    262 	}
    263 	return 0;
    264 }
    265 
    266 
    267 int check_40mhz_2g4(struct hostapd_hw_modes *mode,
    268 		    struct wpa_scan_results *scan_res, int pri_chan,
    269 		    int sec_chan)
    270 {
    271 	int pri_freq, sec_freq;
    272 	int affected_start, affected_end;
    273 	size_t i;
    274 
    275 	if (!mode || !scan_res || !pri_chan || !sec_chan ||
    276 	    pri_chan == sec_chan)
    277 		return 0;
    278 
    279 	pri_freq = hw_get_freq(mode, pri_chan);
    280 	sec_freq = hw_get_freq(mode, sec_chan);
    281 
    282 	affected_start = (pri_freq + sec_freq) / 2 - 25;
    283 	affected_end = (pri_freq + sec_freq) / 2 + 25;
    284 	wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
    285 		   affected_start, affected_end);
    286 	for (i = 0; i < scan_res->num; i++) {
    287 		struct wpa_scan_res *bss = scan_res->res[i];
    288 		int pri = bss->freq;
    289 		int sec = pri;
    290 		struct ieee802_11_elems elems;
    291 
    292 		/* Check for overlapping 20 MHz BSS */
    293 		if (check_20mhz_bss(bss, pri_freq, affected_start,
    294 				    affected_end)) {
    295 			wpa_printf(MSG_DEBUG,
    296 				   "Overlapping 20 MHz BSS is found");
    297 			return 0;
    298 		}
    299 
    300 		get_pri_sec_chan(bss, &pri_chan, &sec_chan);
    301 
    302 		if (sec_chan) {
    303 			if (sec_chan < pri_chan)
    304 				sec = pri - 20;
    305 			else
    306 				sec = pri + 20;
    307 		}
    308 
    309 		if ((pri < affected_start || pri > affected_end) &&
    310 		    (sec < affected_start || sec > affected_end))
    311 			continue; /* not within affected channel range */
    312 
    313 		wpa_printf(MSG_DEBUG, "Neighboring BSS: " MACSTR
    314 			   " freq=%d pri=%d sec=%d",
    315 			   MAC2STR(bss->bssid), bss->freq, pri_chan, sec_chan);
    316 
    317 		if (sec_chan) {
    318 			if (pri_freq != pri || sec_freq != sec) {
    319 				wpa_printf(MSG_DEBUG,
    320 					   "40 MHz pri/sec mismatch with BSS "
    321 					   MACSTR
    322 					   " <%d,%d> (chan=%d%c) vs. <%d,%d>",
    323 					   MAC2STR(bss->bssid),
    324 					   pri, sec, pri_chan,
    325 					   sec > pri ? '+' : '-',
    326 					   pri_freq, sec_freq);
    327 				return 0;
    328 			}
    329 		}
    330 
    331 		ieee802_11_parse_elems((u8 *) (bss + 1), bss->ie_len, &elems,
    332 				       0);
    333 		if (elems.ht_capabilities) {
    334 			struct ieee80211_ht_capabilities *ht_cap =
    335 				(struct ieee80211_ht_capabilities *)
    336 				elems.ht_capabilities;
    337 
    338 			if (le_to_host16(ht_cap->ht_capabilities_info) &
    339 			    HT_CAP_INFO_40MHZ_INTOLERANT) {
    340 				wpa_printf(MSG_DEBUG,
    341 					   "40 MHz Intolerant is set on channel %d in BSS "
    342 					   MACSTR, pri, MAC2STR(bss->bssid));
    343 				return 0;
    344 			}
    345 		}
    346 	}
    347 
    348 	return 1;
    349 }
    350 
    351 
    352 int hostapd_set_freq_params(struct hostapd_freq_params *data,
    353 			    enum hostapd_hw_mode mode,
    354 			    int freq, int channel, int ht_enabled,
    355 			    int vht_enabled, int sec_channel_offset,
    356 			    int vht_oper_chwidth, int center_segment0,
    357 			    int center_segment1, u32 vht_caps)
    358 {
    359 	os_memset(data, 0, sizeof(*data));
    360 	data->mode = mode;
    361 	data->freq = freq;
    362 	data->channel = channel;
    363 	data->ht_enabled = ht_enabled;
    364 	data->vht_enabled = vht_enabled;
    365 	data->sec_channel_offset = sec_channel_offset;
    366 	data->center_freq1 = freq + sec_channel_offset * 10;
    367 	data->center_freq2 = 0;
    368 	data->bandwidth = sec_channel_offset ? 40 : 20;
    369 
    370 	if (data->vht_enabled) switch (vht_oper_chwidth) {
    371 	case VHT_CHANWIDTH_USE_HT:
    372 		if (center_segment1 ||
    373 		    (center_segment0 != 0 &&
    374 		     5000 + center_segment0 * 5 != data->center_freq1 &&
    375 		     2407 + center_segment0 * 5 != data->center_freq1))
    376 			return -1;
    377 		break;
    378 	case VHT_CHANWIDTH_80P80MHZ:
    379 		if (!(vht_caps & VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)) {
    380 			wpa_printf(MSG_ERROR,
    381 				   "80+80 channel width is not supported!");
    382 			return -1;
    383 		}
    384 		if (center_segment1 == center_segment0 + 4 ||
    385 		    center_segment1 == center_segment0 - 4)
    386 			return -1;
    387 		data->center_freq2 = 5000 + center_segment1 * 5;
    388 		/* fall through */
    389 	case VHT_CHANWIDTH_80MHZ:
    390 		data->bandwidth = 80;
    391 		if ((vht_oper_chwidth == 1 && center_segment1) ||
    392 		    (vht_oper_chwidth == 3 && !center_segment1) ||
    393 		    !sec_channel_offset)
    394 			return -1;
    395 		if (!center_segment0) {
    396 			if (channel <= 48)
    397 				center_segment0 = 42;
    398 			else if (channel <= 64)
    399 				center_segment0 = 58;
    400 			else if (channel <= 112)
    401 				center_segment0 = 106;
    402 			else if (channel <= 128)
    403 				center_segment0 = 122;
    404 			else if (channel <= 144)
    405 				center_segment0 = 138;
    406 			else if (channel <= 161)
    407 				center_segment0 = 155;
    408 			data->center_freq1 = 5000 + center_segment0 * 5;
    409 		} else {
    410 			/*
    411 			 * Note: HT/VHT config and params are coupled. Check if
    412 			 * HT40 channel band is in VHT80 Pri channel band
    413 			 * configuration.
    414 			 */
    415 			if (center_segment0 == channel + 6 ||
    416 			    center_segment0 == channel + 2 ||
    417 			    center_segment0 == channel - 2 ||
    418 			    center_segment0 == channel - 6)
    419 				data->center_freq1 = 5000 + center_segment0 * 5;
    420 			else
    421 				return -1;
    422 		}
    423 		break;
    424 	case VHT_CHANWIDTH_160MHZ:
    425 		data->bandwidth = 160;
    426 		if (!(vht_caps & (VHT_CAP_SUPP_CHAN_WIDTH_160MHZ |
    427 				  VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))) {
    428 			wpa_printf(MSG_ERROR,
    429 				   "160MHZ channel width is not supported!");
    430 			return -1;
    431 		}
    432 		if (center_segment1)
    433 			return -1;
    434 		if (!sec_channel_offset)
    435 			return -1;
    436 		/*
    437 		 * Note: HT/VHT config and params are coupled. Check if
    438 		 * HT40 channel band is in VHT160 channel band configuration.
    439 		 */
    440 		if (center_segment0 == channel + 14 ||
    441 		    center_segment0 == channel + 10 ||
    442 		    center_segment0 == channel + 6 ||
    443 		    center_segment0 == channel + 2 ||
    444 		    center_segment0 == channel - 2 ||
    445 		    center_segment0 == channel - 6 ||
    446 		    center_segment0 == channel - 10 ||
    447 		    center_segment0 == channel - 14)
    448 			data->center_freq1 = 5000 + center_segment0 * 5;
    449 		else
    450 			return -1;
    451 		break;
    452 	}
    453 
    454 	return 0;
    455 }
    456