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@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 */
32struct 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 */
56struct 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
64static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
65static void gas_query_timeout(void *eloop_data, void *user_ctx);
66
67
68static 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 */
83struct 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
98static 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
121static 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
140static 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 */
165void 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
180static struct gas_query_pending *
181gas_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
193static 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
205static 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
246static 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
256static 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
284static 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
305static 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
316static 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
332static 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
363static 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 */
436int 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
570static 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
582static 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
596static 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	struct wpa_supplicant *wpa_s = gas->wpa_s;
601
602	if (deinit) {
603		if (work->started) {
604			gas->work = NULL;
605			gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
606			return;
607		}
608
609		gas_query_free(query, 1);
610		return;
611	}
612
613	if (wpas_update_random_addr_disassoc(wpa_s) < 0) {
614		wpa_msg(wpa_s, MSG_INFO,
615			"Failed to assign random MAC address for GAS");
616		gas_query_free(query, 1);
617		radio_work_done(work);
618		return;
619	}
620
621	gas->work = work;
622
623	if (gas_query_tx(gas, query, query->req) < 0) {
624		wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
625			   MACSTR, MAC2STR(query->addr));
626		gas_query_free(query, 1);
627		return;
628	}
629	gas->current = query;
630
631	wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
632		   query->dialog_token);
633	eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
634			       gas_query_timeout, gas, query);
635
636}
637
638
639/**
640 * gas_query_req - Request a GAS query
641 * @gas: GAS query data from gas_query_init()
642 * @dst: Destination MAC address for the query
643 * @freq: Frequency (in MHz) for the channel on which to send the query
644 * @req: GAS query payload (to be freed by gas_query module in case of success
645 *	return)
646 * @cb: Callback function for reporting GAS query result and response
647 * @ctx: Context pointer to use with the @cb call
648 * Returns: dialog token (>= 0) on success or -1 on failure
649 */
650int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
651		  struct wpabuf *req,
652		  void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
653			     enum gas_query_result result,
654			     const struct wpabuf *adv_proto,
655			     const struct wpabuf *resp, u16 status_code),
656		  void *ctx)
657{
658	struct gas_query_pending *query;
659	int dialog_token;
660	static int next_start = 0;
661
662	if (wpabuf_len(req) < 3)
663		return -1;
664
665	for (dialog_token = 0; dialog_token < 256; dialog_token++) {
666		if (gas_query_dialog_token_available(
667			    gas, dst, (next_start + dialog_token) % 256))
668			break;
669	}
670	if (dialog_token == 256)
671		return -1; /* Too many pending queries */
672	dialog_token = (next_start + dialog_token) % 256;
673	next_start = (dialog_token + 1) % 256;
674
675	query = os_zalloc(sizeof(*query));
676	if (query == NULL)
677		return -1;
678
679	query->gas = gas;
680	os_memcpy(query->addr, dst, ETH_ALEN);
681	query->dialog_token = dialog_token;
682	query->freq = freq;
683	query->cb = cb;
684	query->ctx = ctx;
685	query->req = req;
686	dl_list_add(&gas->pending, &query->list);
687
688	*(wpabuf_mhead_u8(req) + 2) = dialog_token;
689
690	wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
691		" dialog_token=%u freq=%d",
692		MAC2STR(query->addr), query->dialog_token, query->freq);
693
694	if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
695			   query) < 0) {
696		gas_query_free(query, 1);
697		return -1;
698	}
699
700	return dialog_token;
701}
702
703
704/**
705 * gas_query_cancel - Cancel a pending GAS query
706 * @gas: GAS query data from gas_query_init()
707 * @dst: Destination MAC address for the query
708 * @dialog_token: Dialog token from gas_query_req()
709 */
710void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
711{
712	struct gas_query_pending *query;
713
714	query = gas_query_get_pending(gas, dst, dialog_token);
715	if (query)
716		gas_query_done(gas, query, GAS_QUERY_CANCELLED);
717
718}
719