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      1 /*
      2  * Generic advertisement service (GAS) query
      3  * Copyright (c) 2009, Atheros Communications
      4  * Copyright (c) 2011-2014, Qualcomm Atheros, Inc.
      5  * Copyright (c) 2011-2014, Jouni Malinen <j (at) w1.fi>
      6  *
      7  * This software may be distributed under the terms of the BSD license.
      8  * See README for more details.
      9  */
     10 
     11 #include "includes.h"
     12 
     13 #include "common.h"
     14 #include "utils/eloop.h"
     15 #include "common/ieee802_11_defs.h"
     16 #include "common/gas.h"
     17 #include "common/wpa_ctrl.h"
     18 #include "rsn_supp/wpa.h"
     19 #include "wpa_supplicant_i.h"
     20 #include "driver_i.h"
     21 #include "offchannel.h"
     22 #include "gas_query.h"
     23 
     24 
     25 /** GAS query timeout in seconds */
     26 #define GAS_QUERY_TIMEOUT_PERIOD 2
     27 
     28 
     29 /**
     30  * struct gas_query_pending - Pending GAS query
     31  */
     32 struct gas_query_pending {
     33 	struct dl_list list;
     34 	struct gas_query *gas;
     35 	u8 addr[ETH_ALEN];
     36 	u8 dialog_token;
     37 	u8 next_frag_id;
     38 	unsigned int wait_comeback:1;
     39 	unsigned int offchannel_tx_started:1;
     40 	int freq;
     41 	u16 status_code;
     42 	struct wpabuf *req;
     43 	struct wpabuf *adv_proto;
     44 	struct wpabuf *resp;
     45 	struct os_reltime last_oper;
     46 	void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
     47 		   enum gas_query_result result,
     48 		   const struct wpabuf *adv_proto,
     49 		   const struct wpabuf *resp, u16 status_code);
     50 	void *ctx;
     51 };
     52 
     53 /**
     54  * struct gas_query - Internal GAS query data
     55  */
     56 struct gas_query {
     57 	struct wpa_supplicant *wpa_s;
     58 	struct dl_list pending; /* struct gas_query_pending */
     59 	struct gas_query_pending *current;
     60 	struct wpa_radio_work *work;
     61 };
     62 
     63 
     64 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
     65 static void gas_query_timeout(void *eloop_data, void *user_ctx);
     66 
     67 
     68 static int ms_from_time(struct os_reltime *last)
     69 {
     70 	struct os_reltime now, res;
     71 
     72 	os_get_reltime(&now);
     73 	os_reltime_sub(&now, last, &res);
     74 	return res.sec * 1000 + res.usec / 1000;
     75 }
     76 
     77 
     78 /**
     79  * gas_query_init - Initialize GAS query component
     80  * @wpa_s: Pointer to wpa_supplicant data
     81  * Returns: Pointer to GAS query data or %NULL on failure
     82  */
     83 struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
     84 {
     85 	struct gas_query *gas;
     86 
     87 	gas = os_zalloc(sizeof(*gas));
     88 	if (gas == NULL)
     89 		return NULL;
     90 
     91 	gas->wpa_s = wpa_s;
     92 	dl_list_init(&gas->pending);
     93 
     94 	return gas;
     95 }
     96 
     97 
     98 static const char * gas_result_txt(enum gas_query_result result)
     99 {
    100 	switch (result) {
    101 	case GAS_QUERY_SUCCESS:
    102 		return "SUCCESS";
    103 	case GAS_QUERY_FAILURE:
    104 		return "FAILURE";
    105 	case GAS_QUERY_TIMEOUT:
    106 		return "TIMEOUT";
    107 	case GAS_QUERY_PEER_ERROR:
    108 		return "PEER_ERROR";
    109 	case GAS_QUERY_INTERNAL_ERROR:
    110 		return "INTERNAL_ERROR";
    111 	case GAS_QUERY_CANCELLED:
    112 		return "CANCELLED";
    113 	case GAS_QUERY_DELETED_AT_DEINIT:
    114 		return "DELETED_AT_DEINIT";
    115 	}
    116 
    117 	return "N/A";
    118 }
    119 
    120 
    121 static void gas_query_free(struct gas_query_pending *query, int del_list)
    122 {
    123 	struct gas_query *gas = query->gas;
    124 
    125 	if (del_list)
    126 		dl_list_del(&query->list);
    127 
    128 	if (gas->work && gas->work->ctx == query) {
    129 		radio_work_done(gas->work);
    130 		gas->work = NULL;
    131 	}
    132 
    133 	wpabuf_free(query->req);
    134 	wpabuf_free(query->adv_proto);
    135 	wpabuf_free(query->resp);
    136 	os_free(query);
    137 }
    138 
    139 
    140 static void gas_query_done(struct gas_query *gas,
    141 			   struct gas_query_pending *query,
    142 			   enum gas_query_result result)
    143 {
    144 	wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_DONE "addr=" MACSTR
    145 		" dialog_token=%u freq=%d status_code=%u result=%s",
    146 		MAC2STR(query->addr), query->dialog_token, query->freq,
    147 		query->status_code, gas_result_txt(result));
    148 	if (gas->current == query)
    149 		gas->current = NULL;
    150 	if (query->offchannel_tx_started)
    151 		offchannel_send_action_done(gas->wpa_s);
    152 	eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
    153 	eloop_cancel_timeout(gas_query_timeout, gas, query);
    154 	dl_list_del(&query->list);
    155 	query->cb(query->ctx, query->addr, query->dialog_token, result,
    156 		  query->adv_proto, query->resp, query->status_code);
    157 	gas_query_free(query, 0);
    158 }
    159 
    160 
    161 /**
    162  * gas_query_deinit - Deinitialize GAS query component
    163  * @gas: GAS query data from gas_query_init()
    164  */
    165 void gas_query_deinit(struct gas_query *gas)
    166 {
    167 	struct gas_query_pending *query, *next;
    168 
    169 	if (gas == NULL)
    170 		return;
    171 
    172 	dl_list_for_each_safe(query, next, &gas->pending,
    173 			      struct gas_query_pending, list)
    174 		gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
    175 
    176 	os_free(gas);
    177 }
    178 
    179 
    180 static struct gas_query_pending *
    181 gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
    182 {
    183 	struct gas_query_pending *q;
    184 	dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
    185 		if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
    186 		    q->dialog_token == dialog_token)
    187 			return q;
    188 	}
    189 	return NULL;
    190 }
    191 
    192 
    193 static int gas_query_append(struct gas_query_pending *query, const u8 *data,
    194 			    size_t len)
    195 {
    196 	if (wpabuf_resize(&query->resp, len) < 0) {
    197 		wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
    198 		return -1;
    199 	}
    200 	wpabuf_put_data(query->resp, data, len);
    201 	return 0;
    202 }
    203 
    204 
    205 static void gas_query_tx_status(struct wpa_supplicant *wpa_s,
    206 				unsigned int freq, const u8 *dst,
    207 				const u8 *src, const u8 *bssid,
    208 				const u8 *data, size_t data_len,
    209 				enum offchannel_send_action_result result)
    210 {
    211 	struct gas_query_pending *query;
    212 	struct gas_query *gas = wpa_s->gas;
    213 	int dur;
    214 
    215 	if (gas->current == NULL) {
    216 		wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
    217 			   MACSTR " result=%d - no query in progress",
    218 			   freq, MAC2STR(dst), result);
    219 		return;
    220 	}
    221 
    222 	query = gas->current;
    223 
    224 	dur = ms_from_time(&query->last_oper);
    225 	wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
    226 		   " result=%d query=%p dialog_token=%u dur=%d ms",
    227 		   freq, MAC2STR(dst), result, query, query->dialog_token, dur);
    228 	if (os_memcmp(dst, query->addr, ETH_ALEN) != 0) {
    229 		wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
    230 		return;
    231 	}
    232 	os_get_reltime(&query->last_oper);
    233 
    234 	if (result == OFFCHANNEL_SEND_ACTION_SUCCESS) {
    235 		eloop_cancel_timeout(gas_query_timeout, gas, query);
    236 		eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
    237 				       gas_query_timeout, gas, query);
    238 	}
    239 	if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
    240 		eloop_cancel_timeout(gas_query_timeout, gas, query);
    241 		eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
    242 	}
    243 }
    244 
    245 
    246 static int pmf_in_use(struct wpa_supplicant *wpa_s, const u8 *addr)
    247 {
    248 	if (wpa_s->current_ssid == NULL ||
    249 	    wpa_s->wpa_state < WPA_4WAY_HANDSHAKE ||
    250 	    os_memcmp(addr, wpa_s->bssid, ETH_ALEN) != 0)
    251 		return 0;
    252 	return wpa_sm_pmf_enabled(wpa_s->wpa);
    253 }
    254 
    255 
    256 static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
    257 			struct wpabuf *req)
    258 {
    259 	unsigned int wait_time;
    260 	int res, prot = pmf_in_use(gas->wpa_s, query->addr);
    261 
    262 	wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
    263 		   "freq=%d prot=%d", MAC2STR(query->addr),
    264 		   (unsigned int) wpabuf_len(req), query->freq, prot);
    265 	if (prot) {
    266 		u8 *categ = wpabuf_mhead_u8(req);
    267 		*categ = WLAN_ACTION_PROTECTED_DUAL;
    268 	}
    269 	os_get_reltime(&query->last_oper);
    270 	wait_time = 1000;
    271 	if (gas->wpa_s->max_remain_on_chan &&
    272 	    wait_time > gas->wpa_s->max_remain_on_chan)
    273 		wait_time = gas->wpa_s->max_remain_on_chan;
    274 	res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
    275 				     gas->wpa_s->own_addr, query->addr,
    276 				     wpabuf_head(req), wpabuf_len(req),
    277 				     wait_time, gas_query_tx_status, 0);
    278 	if (res == 0)
    279 		query->offchannel_tx_started = 1;
    280 	return res;
    281 }
    282 
    283 
    284 static void gas_query_tx_comeback_req(struct gas_query *gas,
    285 				      struct gas_query_pending *query)
    286 {
    287 	struct wpabuf *req;
    288 
    289 	req = gas_build_comeback_req(query->dialog_token);
    290 	if (req == NULL) {
    291 		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    292 		return;
    293 	}
    294 
    295 	if (gas_query_tx(gas, query, req) < 0) {
    296 		wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
    297 			   MACSTR, MAC2STR(query->addr));
    298 		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    299 	}
    300 
    301 	wpabuf_free(req);
    302 }
    303 
    304 
    305 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
    306 {
    307 	struct gas_query *gas = eloop_data;
    308 	struct gas_query_pending *query = user_ctx;
    309 
    310 	wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
    311 		   MAC2STR(query->addr));
    312 	gas_query_tx_comeback_req(gas, query);
    313 }
    314 
    315 
    316 static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
    317 					    struct gas_query_pending *query,
    318 					    u16 comeback_delay)
    319 {
    320 	unsigned int secs, usecs;
    321 
    322 	secs = (comeback_delay * 1024) / 1000000;
    323 	usecs = comeback_delay * 1024 - secs * 1000000;
    324 	wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
    325 		   " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
    326 	eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
    327 	eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
    328 			       gas, query);
    329 }
    330 
    331 
    332 static void gas_query_rx_initial(struct gas_query *gas,
    333 				 struct gas_query_pending *query,
    334 				 const u8 *adv_proto, const u8 *resp,
    335 				 size_t len, u16 comeback_delay)
    336 {
    337 	wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
    338 		   MACSTR " (dialog_token=%u comeback_delay=%u)",
    339 		   MAC2STR(query->addr), query->dialog_token, comeback_delay);
    340 
    341 	query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
    342 	if (query->adv_proto == NULL) {
    343 		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    344 		return;
    345 	}
    346 
    347 	if (comeback_delay) {
    348 		query->wait_comeback = 1;
    349 		gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
    350 		return;
    351 	}
    352 
    353 	/* Query was completed without comeback mechanism */
    354 	if (gas_query_append(query, resp, len) < 0) {
    355 		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    356 		return;
    357 	}
    358 
    359 	gas_query_done(gas, query, GAS_QUERY_SUCCESS);
    360 }
    361 
    362 
    363 static void gas_query_rx_comeback(struct gas_query *gas,
    364 				  struct gas_query_pending *query,
    365 				  const u8 *adv_proto, const u8 *resp,
    366 				  size_t len, u8 frag_id, u8 more_frags,
    367 				  u16 comeback_delay)
    368 {
    369 	wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
    370 		   MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
    371 		   "comeback_delay=%u)",
    372 		   MAC2STR(query->addr), query->dialog_token, frag_id,
    373 		   more_frags, comeback_delay);
    374 
    375 	if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
    376 	    os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
    377 		      wpabuf_len(query->adv_proto)) != 0) {
    378 		wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
    379 			   "between initial and comeback response from "
    380 			   MACSTR, MAC2STR(query->addr));
    381 		gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
    382 		return;
    383 	}
    384 
    385 	if (comeback_delay) {
    386 		if (frag_id) {
    387 			wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
    388 				   "with non-zero frag_id and comeback_delay "
    389 				   "from " MACSTR, MAC2STR(query->addr));
    390 			gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
    391 			return;
    392 		}
    393 		gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
    394 		return;
    395 	}
    396 
    397 	if (frag_id != query->next_frag_id) {
    398 		wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
    399 			   "from " MACSTR, MAC2STR(query->addr));
    400 		if (frag_id + 1 == query->next_frag_id) {
    401 			wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
    402 				   "retry of previous fragment");
    403 			return;
    404 		}
    405 		gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
    406 		return;
    407 	}
    408 	query->next_frag_id++;
    409 
    410 	if (gas_query_append(query, resp, len) < 0) {
    411 		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    412 		return;
    413 	}
    414 
    415 	if (more_frags) {
    416 		gas_query_tx_comeback_req(gas, query);
    417 		return;
    418 	}
    419 
    420 	gas_query_done(gas, query, GAS_QUERY_SUCCESS);
    421 }
    422 
    423 
    424 /**
    425  * gas_query_rx - Indicate reception of a Public Action or Protected Dual frame
    426  * @gas: GAS query data from gas_query_init()
    427  * @da: Destination MAC address of the Action frame
    428  * @sa: Source MAC address of the Action frame
    429  * @bssid: BSSID of the Action frame
    430  * @categ: Category of the Action frame
    431  * @data: Payload of the Action frame
    432  * @len: Length of @data
    433  * @freq: Frequency (in MHz) on which the frame was received
    434  * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
    435  */
    436 int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
    437 		 const u8 *bssid, u8 categ, const u8 *data, size_t len,
    438 		 int freq)
    439 {
    440 	struct gas_query_pending *query;
    441 	u8 action, dialog_token, frag_id = 0, more_frags = 0;
    442 	u16 comeback_delay, resp_len;
    443 	const u8 *pos, *adv_proto;
    444 	int prot, pmf;
    445 
    446 	if (gas == NULL || len < 4)
    447 		return -1;
    448 
    449 	prot = categ == WLAN_ACTION_PROTECTED_DUAL;
    450 	pmf = pmf_in_use(gas->wpa_s, bssid);
    451 	if (prot && !pmf) {
    452 		wpa_printf(MSG_DEBUG, "GAS: Drop unexpected protected GAS frame when PMF is disabled");
    453 		return 0;
    454 	}
    455 	if (!prot && pmf) {
    456 		wpa_printf(MSG_DEBUG, "GAS: Drop unexpected unprotected GAS frame when PMF is enabled");
    457 		return 0;
    458 	}
    459 
    460 	pos = data;
    461 	action = *pos++;
    462 	dialog_token = *pos++;
    463 
    464 	if (action != WLAN_PA_GAS_INITIAL_RESP &&
    465 	    action != WLAN_PA_GAS_COMEBACK_RESP)
    466 		return -1; /* Not a GAS response */
    467 
    468 	query = gas_query_get_pending(gas, sa, dialog_token);
    469 	if (query == NULL) {
    470 		wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
    471 			   " dialog token %u", MAC2STR(sa), dialog_token);
    472 		return -1;
    473 	}
    474 
    475 	wpa_printf(MSG_DEBUG, "GAS: Response in %d ms from " MACSTR,
    476 		   ms_from_time(&query->last_oper), MAC2STR(sa));
    477 
    478 	if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
    479 		wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
    480 			   MACSTR " dialog token %u when waiting for comeback "
    481 			   "response", MAC2STR(sa), dialog_token);
    482 		return 0;
    483 	}
    484 
    485 	if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
    486 		wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
    487 			   MACSTR " dialog token %u when waiting for initial "
    488 			   "response", MAC2STR(sa), dialog_token);
    489 		return 0;
    490 	}
    491 
    492 	query->status_code = WPA_GET_LE16(pos);
    493 	pos += 2;
    494 
    495 	if (query->status_code == WLAN_STATUS_QUERY_RESP_OUTSTANDING &&
    496 	    action == WLAN_PA_GAS_COMEBACK_RESP) {
    497 		wpa_printf(MSG_DEBUG, "GAS: Allow non-zero status for outstanding comeback response");
    498 	} else if (query->status_code != WLAN_STATUS_SUCCESS) {
    499 		wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
    500 			   "%u failed - status code %u",
    501 			   MAC2STR(sa), dialog_token, query->status_code);
    502 		gas_query_done(gas, query, GAS_QUERY_FAILURE);
    503 		return 0;
    504 	}
    505 
    506 	if (action == WLAN_PA_GAS_COMEBACK_RESP) {
    507 		if (pos + 1 > data + len)
    508 			return 0;
    509 		frag_id = *pos & 0x7f;
    510 		more_frags = (*pos & 0x80) >> 7;
    511 		pos++;
    512 	}
    513 
    514 	/* Comeback Delay */
    515 	if (pos + 2 > data + len)
    516 		return 0;
    517 	comeback_delay = WPA_GET_LE16(pos);
    518 	pos += 2;
    519 
    520 	/* Advertisement Protocol element */
    521 	if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
    522 		wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
    523 			   "Protocol element in the response from " MACSTR,
    524 			   MAC2STR(sa));
    525 		return 0;
    526 	}
    527 
    528 	if (*pos != WLAN_EID_ADV_PROTO) {
    529 		wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
    530 			   "Protocol element ID %u in response from " MACSTR,
    531 			   *pos, MAC2STR(sa));
    532 		return 0;
    533 	}
    534 
    535 	adv_proto = pos;
    536 	pos += 2 + pos[1];
    537 
    538 	/* Query Response Length */
    539 	if (pos + 2 > data + len) {
    540 		wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
    541 		return 0;
    542 	}
    543 	resp_len = WPA_GET_LE16(pos);
    544 	pos += 2;
    545 
    546 	if (pos + resp_len > data + len) {
    547 		wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
    548 			   "response from " MACSTR, MAC2STR(sa));
    549 		return 0;
    550 	}
    551 
    552 	if (pos + resp_len < data + len) {
    553 		wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
    554 			   "after Query Response from " MACSTR,
    555 			   (unsigned int) (data + len - pos - resp_len),
    556 			   MAC2STR(sa));
    557 	}
    558 
    559 	if (action == WLAN_PA_GAS_COMEBACK_RESP)
    560 		gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
    561 				      frag_id, more_frags, comeback_delay);
    562 	else
    563 		gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
    564 				     comeback_delay);
    565 
    566 	return 0;
    567 }
    568 
    569 
    570 static void gas_query_timeout(void *eloop_data, void *user_ctx)
    571 {
    572 	struct gas_query *gas = eloop_data;
    573 	struct gas_query_pending *query = user_ctx;
    574 
    575 	wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
    576 		   " dialog token %u",
    577 		   MAC2STR(query->addr), query->dialog_token);
    578 	gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
    579 }
    580 
    581 
    582 static int gas_query_dialog_token_available(struct gas_query *gas,
    583 					    const u8 *dst, u8 dialog_token)
    584 {
    585 	struct gas_query_pending *q;
    586 	dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
    587 		if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
    588 		    dialog_token == q->dialog_token)
    589 			return 0;
    590 	}
    591 
    592 	return 1;
    593 }
    594 
    595 
    596 static void gas_query_start_cb(struct wpa_radio_work *work, int deinit)
    597 {
    598 	struct gas_query_pending *query = work->ctx;
    599 	struct gas_query *gas = query->gas;
    600 
    601 	if (deinit) {
    602 		if (work->started) {
    603 			gas->work = NULL;
    604 			gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
    605 			return;
    606 		}
    607 
    608 		gas_query_free(query, 1);
    609 		return;
    610 	}
    611 
    612 	gas->work = work;
    613 
    614 	if (gas_query_tx(gas, query, query->req) < 0) {
    615 		wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
    616 			   MACSTR, MAC2STR(query->addr));
    617 		gas_query_free(query, 1);
    618 		return;
    619 	}
    620 	gas->current = query;
    621 
    622 	wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
    623 		   query->dialog_token);
    624 	eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
    625 			       gas_query_timeout, gas, query);
    626 
    627 }
    628 
    629 
    630 /**
    631  * gas_query_req - Request a GAS query
    632  * @gas: GAS query data from gas_query_init()
    633  * @dst: Destination MAC address for the query
    634  * @freq: Frequency (in MHz) for the channel on which to send the query
    635  * @req: GAS query payload (to be freed by gas_query module in case of success
    636  *	return)
    637  * @cb: Callback function for reporting GAS query result and response
    638  * @ctx: Context pointer to use with the @cb call
    639  * Returns: dialog token (>= 0) on success or -1 on failure
    640  */
    641 int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
    642 		  struct wpabuf *req,
    643 		  void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
    644 			     enum gas_query_result result,
    645 			     const struct wpabuf *adv_proto,
    646 			     const struct wpabuf *resp, u16 status_code),
    647 		  void *ctx)
    648 {
    649 	struct gas_query_pending *query;
    650 	int dialog_token;
    651 	static int next_start = 0;
    652 
    653 	if (wpabuf_len(req) < 3)
    654 		return -1;
    655 
    656 	for (dialog_token = 0; dialog_token < 256; dialog_token++) {
    657 		if (gas_query_dialog_token_available(
    658 			    gas, dst, (next_start + dialog_token) % 256))
    659 			break;
    660 	}
    661 	if (dialog_token == 256)
    662 		return -1; /* Too many pending queries */
    663 	dialog_token = (next_start + dialog_token) % 256;
    664 	next_start = (dialog_token + 1) % 256;
    665 
    666 	query = os_zalloc(sizeof(*query));
    667 	if (query == NULL)
    668 		return -1;
    669 
    670 	query->gas = gas;
    671 	os_memcpy(query->addr, dst, ETH_ALEN);
    672 	query->dialog_token = dialog_token;
    673 	query->freq = freq;
    674 	query->cb = cb;
    675 	query->ctx = ctx;
    676 	query->req = req;
    677 	dl_list_add(&gas->pending, &query->list);
    678 
    679 	*(wpabuf_mhead_u8(req) + 2) = dialog_token;
    680 
    681 	wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
    682 		" dialog_token=%u freq=%d",
    683 		MAC2STR(query->addr), query->dialog_token, query->freq);
    684 
    685 	if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
    686 			   query) < 0) {
    687 		gas_query_free(query, 1);
    688 		return -1;
    689 	}
    690 
    691 	return dialog_token;
    692 }
    693 
    694 
    695 /**
    696  * gas_query_cancel - Cancel a pending GAS query
    697  * @gas: GAS query data from gas_query_init()
    698  * @dst: Destination MAC address for the query
    699  * @dialog_token: Dialog token from gas_query_req()
    700  */
    701 void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
    702 {
    703 	struct gas_query_pending *query;
    704 
    705 	query = gas_query_get_pending(gas, dst, dialog_token);
    706 	if (query)
    707 		gas_query_done(gas, query, GAS_QUERY_CANCELLED);
    708 
    709 }
    710