text: /*
   * Generic advertisement service (GAS) query
   * Copyright (c) 2009, Atheros Communications
   * Copyright (c) 2011-2014, Qualcomm Atheros, Inc.
   * Copyright (c) 2011-2014, Jouni Malinen <j@w1.fi>
   *
   * This software may be distributed under the terms of the BSD license.
   * See README for more details.
   */
  
  #include "includes.h"
  
  #include "common.h"
  #include "utils/eloop.h"
  #include "common/ieee802_11_defs.h"
  #include "common/gas.h"
  #include "common/wpa_ctrl.h"
  #include "rsn_supp/wpa.h"
  #include "wpa_supplicant_i.h"
  #include "config.h"
  #include "driver_i.h"
  #include "offchannel.h"
  #include "gas_query.h"
  
  
  /** GAS query timeout in seconds */
  #define GAS_QUERY_TIMEOUT_PERIOD 2
  
  /* GAS query wait-time / duration in ms */
  #define GAS_QUERY_WAIT_TIME_INITIAL 1000
  #define GAS_QUERY_WAIT_TIME_COMEBACK 150
  
  /**
   * struct gas_query_pending - Pending GAS query
   */
  struct gas_query_pending {
  	struct dl_list list;
  	struct gas_query *gas;
  	u8 addr[ETH_ALEN];
  	u8 dialog_token;
  	u8 next_frag_id;
  	unsigned int wait_comeback:1;
  	unsigned int offchannel_tx_started:1;
  	unsigned int retry:1;
  	int freq;
  	u16 status_code;
  	struct wpabuf *req;
  	struct wpabuf *adv_proto;
  	struct wpabuf *resp;
  	struct os_reltime last_oper;
  	void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
  		   enum gas_query_result result,
  		   const struct wpabuf *adv_proto,
  		   const struct wpabuf *resp, u16 status_code);
  	void *ctx;
  	u8 sa[ETH_ALEN];
  };
  
  /**
   * struct gas_query - Internal GAS query data
   */
  struct gas_query {
  	struct wpa_supplicant *wpa_s;
  	struct dl_list pending; /* struct gas_query_pending */
  	struct gas_query_pending *current;
  	struct wpa_radio_work *work;
  	struct os_reltime last_mac_addr_rand;
  	int last_rand_sa_type;
  	u8 rand_addr[ETH_ALEN];
  };
  
  
  static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
  static void gas_query_timeout(void *eloop_data, void *user_ctx);
  static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx);
  static void gas_query_tx_initial_req(struct gas_query *gas,
  				     struct gas_query_pending *query);
  static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst);
  
  
  static int ms_from_time(struct os_reltime *last)
  {
  	struct os_reltime now, res;
  
  	os_get_reltime(&now);
  	os_reltime_sub(&now, last, &res);
  	return res.sec * 1000 + res.usec / 1000;
  }
  
  
  /**
   * gas_query_init - Initialize GAS query component
   * @wpa_s: Pointer to wpa_supplicant data
   * Returns: Pointer to GAS query data or %NULL on failure
   */
  struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
  {
  	struct gas_query *gas;
  
  	gas = os_zalloc(sizeof(*gas));
  	if (gas == NULL)
  		return NULL;
  
  	gas->wpa_s = wpa_s;
  	dl_list_init(&gas->pending);
  
  	return gas;
  }
  
  
  static const char * gas_result_txt(enum gas_query_result result)
  {
  	switch (result) {
  	case GAS_QUERY_SUCCESS:
  		return "SUCCESS";
  	case GAS_QUERY_FAILURE:
  		return "FAILURE";
  	case GAS_QUERY_TIMEOUT:
  		return "TIMEOUT";
  	case GAS_QUERY_PEER_ERROR:
  		return "PEER_ERROR";
  	case GAS_QUERY_INTERNAL_ERROR:
  		return "INTERNAL_ERROR";
  	case GAS_QUERY_STOPPED:
  		return "STOPPED";
  	case GAS_QUERY_DELETED_AT_DEINIT:
  		return "DELETED_AT_DEINIT";
  	}
  
  	return "N/A";
  }
  
  
  static void gas_query_free(struct gas_query_pending *query, int del_list)
  {
  	struct gas_query *gas = query->gas;
  
  	if (del_list)
  		dl_list_del(&query->list);
  
  	if (gas->work && gas->work->ctx == query) {
  		radio_work_done(gas->work);
  		gas->work = NULL;
  	}
  
  	wpabuf_free(query->req);
  	wpabuf_free(query->adv_proto);
  	wpabuf_free(query->resp);
  	os_free(query);
  }
  
  
  static void gas_query_done(struct gas_query *gas,
  			   struct gas_query_pending *query,
  			   enum gas_query_result result)
  {
  	wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_DONE "addr=" MACSTR
  		" dialog_token=%u freq=%d status_code=%u result=%s",
  		MAC2STR(query->addr), query->dialog_token, query->freq,
  		query->status_code, gas_result_txt(result));
  	if (gas->current == query)
  		gas->current = NULL;
  	if (query->offchannel_tx_started)
  		offchannel_send_action_done(gas->wpa_s);
  	eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  	eloop_cancel_timeout(gas_query_timeout, gas, query);
  	eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);
  	dl_list_del(&query->list);
  	query->cb(query->ctx, query->addr, query->dialog_token, result,
  		  query->adv_proto, query->resp, query->status_code);
  	gas_query_free(query, 0);
  }
  
  
  /**
   * gas_query_deinit - Deinitialize GAS query component
   * @gas: GAS query data from gas_query_init()
   */
  void gas_query_deinit(struct gas_query *gas)
  {
  	struct gas_query_pending *query, *next;
  
  	if (gas == NULL)
  		return;
  
  	dl_list_for_each_safe(query, next, &gas->pending,
  			      struct gas_query_pending, list)
  		gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
  
  	os_free(gas);
  }
  
  
  static struct gas_query_pending *
  gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
  {
  	struct gas_query_pending *q;
  	dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
  		if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
  		    q->dialog_token == dialog_token)
  			return q;
  	}
  	return NULL;
  }
  
  
  static int gas_query_append(struct gas_query_pending *query, const u8 *data,
  			    size_t len)
  {
  	if (wpabuf_resize(&query->resp, len) < 0) {
  		wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
  		return -1;
  	}
  	wpabuf_put_data(query->resp, data, len);
  	return 0;
  }
  
  
  static void gas_query_tx_status(struct wpa_supplicant *wpa_s,
  				unsigned int freq, const u8 *dst,
  				const u8 *src, const u8 *bssid,
  				const u8 *data, size_t data_len,
  				enum offchannel_send_action_result result)
  {
  	struct gas_query_pending *query;
  	struct gas_query *gas = wpa_s->gas;
  	int dur;
  
  	if (gas->current == NULL) {
  		wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
  			   MACSTR " result=%d - no query in progress",
  			   freq, MAC2STR(dst), result);
  		return;
  	}
  
  	query = gas->current;
  
  	dur = ms_from_time(&query->last_oper);
  	wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
  		   " result=%d query=%p dialog_token=%u dur=%d ms",
  		   freq, MAC2STR(dst), result, query, query->dialog_token, dur);
  	if (os_memcmp(dst, query->addr, ETH_ALEN) != 0) {
  		wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
  		return;
  	}
  	os_get_reltime(&query->last_oper);
  
  	if (result == OFFCHANNEL_SEND_ACTION_SUCCESS ||
  	    result == OFFCHANNEL_SEND_ACTION_NO_ACK) {
  		eloop_cancel_timeout(gas_query_timeout, gas, query);
  		if (result == OFFCHANNEL_SEND_ACTION_NO_ACK) {
  			wpa_printf(MSG_DEBUG, "GAS: No ACK to GAS request");
  			eloop_register_timeout(0, 250000,
  					       gas_query_timeout, gas, query);
  		} else {
  			eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
  					       gas_query_timeout, gas, query);
  		}
  		if (query->wait_comeback && !query->retry) {
  			eloop_cancel_timeout(gas_query_rx_comeback_timeout,
  					     gas, query);
  			eloop_register_timeout(
  				0, (GAS_QUERY_WAIT_TIME_COMEBACK + 10) * 1000,
  				gas_query_rx_comeback_timeout, gas, query);
  		}
  	}
  	if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
  		eloop_cancel_timeout(gas_query_timeout, gas, query);
  		eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
  	}
  }
  
  
  static int pmf_in_use(struct wpa_supplicant *wpa_s, const u8 *addr)
  {
  	if (wpa_s->current_ssid == NULL ||
  	    wpa_s->wpa_state < WPA_4WAY_HANDSHAKE ||
  	    os_memcmp(addr, wpa_s->bssid, ETH_ALEN) != 0)
  		return 0;
  	return wpa_sm_pmf_enabled(wpa_s->wpa);
  }
  
  
  static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
  			struct wpabuf *req, unsigned int wait_time)
  {
  	int res, prot = pmf_in_use(gas->wpa_s, query->addr);
  	const u8 *bssid;
  	const u8 wildcard_bssid[ETH_ALEN] = {
  		0xff, 0xff, 0xff, 0xff, 0xff, 0xff
  	};
  
  	wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
  		   "freq=%d prot=%d using src addr " MACSTR,
  		   MAC2STR(query->addr), (unsigned int) wpabuf_len(req),
  		   query->freq, prot, MAC2STR(query->sa));
  	if (prot) {
  		u8 *categ = wpabuf_mhead_u8(req);
  		*categ = WLAN_ACTION_PROTECTED_DUAL;
  	}
  	os_get_reltime(&query->last_oper);
  	if (gas->wpa_s->max_remain_on_chan &&
  	    wait_time > gas->wpa_s->max_remain_on_chan)
  		wait_time = gas->wpa_s->max_remain_on_chan;
  	if (!gas->wpa_s->conf->gas_address3 ||
  	    (gas->wpa_s->current_ssid &&
  	     gas->wpa_s->wpa_state >= WPA_ASSOCIATED &&
  	     os_memcmp(query->addr, gas->wpa_s->bssid, ETH_ALEN) == 0))
  		bssid = query->addr;
  	else
  		bssid = wildcard_bssid;
  
  	res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
  				     query->sa, bssid, wpabuf_head(req),
  				     wpabuf_len(req), wait_time,
  				     gas_query_tx_status, 0);
  
  	if (res == 0)
  		query->offchannel_tx_started = 1;
  	return res;
  }
  
  
  static void gas_query_tx_comeback_req(struct gas_query *gas,
  				      struct gas_query_pending *query)
  {
  	struct wpabuf *req;
  	unsigned int wait_time;
  
  	req = gas_build_comeback_req(query->dialog_token);
  	if (req == NULL) {
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  		return;
  	}
  
  	wait_time = (query->retry || !query->offchannel_tx_started) ?
  		GAS_QUERY_WAIT_TIME_INITIAL : GAS_QUERY_WAIT_TIME_COMEBACK;
  
  	if (gas_query_tx(gas, query, req, wait_time) < 0) {
  		wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
  			   MACSTR, MAC2STR(query->addr));
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  	}
  
  	wpabuf_free(req);
  }
  
  
  static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx)
  {
  	struct gas_query *gas = eloop_data;
  	struct gas_query_pending *query = user_ctx;
  	int dialog_token;
  
  	wpa_printf(MSG_DEBUG,
  		   "GAS: No response to comeback request received (retry=%u)",
  		   query->retry);
  	if (gas->current != query || query->retry)
  		return;
  	dialog_token = gas_query_new_dialog_token(gas, query->addr);
  	if (dialog_token < 0)
  		return;
  	wpa_printf(MSG_DEBUG,
  		   "GAS: Retry GAS query due to comeback response timeout");
  	query->retry = 1;
  	query->dialog_token = dialog_token;
  	*(wpabuf_mhead_u8(query->req) + 2) = dialog_token;
  	query->wait_comeback = 0;
  	query->next_frag_id = 0;
  	wpabuf_free(query->adv_proto);
  	query->adv_proto = NULL;
  	eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  	eloop_cancel_timeout(gas_query_timeout, gas, query);
  	gas_query_tx_initial_req(gas, query);
  }
  
  
  static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
  {
  	struct gas_query *gas = eloop_data;
  	struct gas_query_pending *query = user_ctx;
  
  	wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
  		   MAC2STR(query->addr));
  	gas_query_tx_comeback_req(gas, query);
  }
  
  
  static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
  					    struct gas_query_pending *query,
  					    u16 comeback_delay)
  {
  	unsigned int secs, usecs;
  
  	if (comeback_delay > 1 && query->offchannel_tx_started) {
  		offchannel_send_action_done(gas->wpa_s);
  		query->offchannel_tx_started = 0;
  	}
  
  	secs = (comeback_delay * 1024) / 1000000;
  	usecs = comeback_delay * 1024 - secs * 1000000;
  	wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
  		   " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
  	eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  	eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
  			       gas, query);
  }
  
  
  static void gas_query_rx_initial(struct gas_query *gas,
  				 struct gas_query_pending *query,
  				 const u8 *adv_proto, const u8 *resp,
  				 size_t len, u16 comeback_delay)
  {
  	wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
  		   MACSTR " (dialog_token=%u comeback_delay=%u)",
  		   MAC2STR(query->addr), query->dialog_token, comeback_delay);
  
  	query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
  	if (query->adv_proto == NULL) {
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  		return;
  	}
  
  	if (comeback_delay) {
  		eloop_cancel_timeout(gas_query_timeout, gas, query);
  		query->wait_comeback = 1;
  		gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
  		return;
  	}
  
  	/* Query was completed without comeback mechanism */
  	if (gas_query_append(query, resp, len) < 0) {
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  		return;
  	}
  
  	gas_query_done(gas, query, GAS_QUERY_SUCCESS);
  }
  
  
  static void gas_query_rx_comeback(struct gas_query *gas,
  				  struct gas_query_pending *query,
  				  const u8 *adv_proto, const u8 *resp,
  				  size_t len, u8 frag_id, u8 more_frags,
  				  u16 comeback_delay)
  {
  	wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
  		   MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
  		   "comeback_delay=%u)",
  		   MAC2STR(query->addr), query->dialog_token, frag_id,
  		   more_frags, comeback_delay);
  	eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);
  
  	if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
  	    os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
  		      wpabuf_len(query->adv_proto)) != 0) {
  		wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
  			   "between initial and comeback response from "
  			   MACSTR, MAC2STR(query->addr));
  		gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
  		return;
  	}
  
  	if (comeback_delay) {
  		if (frag_id) {
  			wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
  				   "with non-zero frag_id and comeback_delay "
  				   "from " MACSTR, MAC2STR(query->addr));
  			gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
  			return;
  		}
  		gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
  		return;
  	}
  
  	if (frag_id != query->next_frag_id) {
  		wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
  			   "from " MACSTR, MAC2STR(query->addr));
  		if (frag_id + 1 == query->next_frag_id) {
  			wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
  				   "retry of previous fragment");
  			return;
  		}
  		gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
  		return;
  	}
  	query->next_frag_id++;
  
  	if (gas_query_append(query, resp, len) < 0) {
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  		return;
  	}
  
  	if (more_frags) {
  		gas_query_tx_comeback_req(gas, query);
  		return;
  	}
  
  	gas_query_done(gas, query, GAS_QUERY_SUCCESS);
  }
  
  
  /**
   * gas_query_rx - Indicate reception of a Public Action or Protected Dual frame
   * @gas: GAS query data from gas_query_init()
   * @da: Destination MAC address of the Action frame
   * @sa: Source MAC address of the Action frame
   * @bssid: BSSID of the Action frame
   * @categ: Category of the Action frame
   * @data: Payload of the Action frame
   * @len: Length of @data
   * @freq: Frequency (in MHz) on which the frame was received
   * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
   */
  int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
  		 const u8 *bssid, u8 categ, const u8 *data, size_t len,
  		 int freq)
  {
  	struct gas_query_pending *query;
  	u8 action, dialog_token, frag_id = 0, more_frags = 0;
  	u16 comeback_delay, resp_len;
  	const u8 *pos, *adv_proto;
  	int prot, pmf;
  	unsigned int left;
  
  	if (gas == NULL || len < 4)
  		return -1;
  
  	pos = data;
  	action = *pos++;
  	dialog_token = *pos++;
  
  	if (action != WLAN_PA_GAS_INITIAL_RESP &&
  	    action != WLAN_PA_GAS_COMEBACK_RESP)
  		return -1; /* Not a GAS response */
  
  	prot = categ == WLAN_ACTION_PROTECTED_DUAL;
  	pmf = pmf_in_use(gas->wpa_s, sa);
  	if (prot && !pmf) {
  		wpa_printf(MSG_DEBUG, "GAS: Drop unexpected protected GAS frame when PMF is disabled");
  		return 0;
  	}
  	if (!prot && pmf) {
  		wpa_printf(MSG_DEBUG, "GAS: Drop unexpected unprotected GAS frame when PMF is enabled");
  		return 0;
  	}
  
  	query = gas_query_get_pending(gas, sa, dialog_token);
  	if (query == NULL) {
  		wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
  			   " dialog token %u", MAC2STR(sa), dialog_token);
  		return -1;
  	}
  
  	wpa_printf(MSG_DEBUG, "GAS: Response in %d ms from " MACSTR,
  		   ms_from_time(&query->last_oper), MAC2STR(sa));
  
  	if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
  		wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
  			   MACSTR " dialog token %u when waiting for comeback "
  			   "response", MAC2STR(sa), dialog_token);
  		return 0;
  	}
  
  	if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
  		wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
  			   MACSTR " dialog token %u when waiting for initial "
  			   "response", MAC2STR(sa), dialog_token);
  		return 0;
  	}
  
  	query->status_code = WPA_GET_LE16(pos);
  	pos += 2;
  
  	if (query->status_code == WLAN_STATUS_QUERY_RESP_OUTSTANDING &&
  	    action == WLAN_PA_GAS_COMEBACK_RESP) {
  		wpa_printf(MSG_DEBUG, "GAS: Allow non-zero status for outstanding comeback response");
  	} else if (query->status_code != WLAN_STATUS_SUCCESS) {
  		wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
  			   "%u failed - status code %u",
  			   MAC2STR(sa), dialog_token, query->status_code);
  		gas_query_done(gas, query, GAS_QUERY_FAILURE);
  		return 0;
  	}
  
  	if (action == WLAN_PA_GAS_COMEBACK_RESP) {
  		if (pos + 1 > data + len)
  			return 0;
  		frag_id = *pos & 0x7f;
  		more_frags = (*pos & 0x80) >> 7;
  		pos++;
  	}
  
  	/* Comeback Delay */
  	if (pos + 2 > data + len)
  		return 0;
  	comeback_delay = WPA_GET_LE16(pos);
  	pos += 2;
  
  	/* Advertisement Protocol element */
  	if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
  		wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
  			   "Protocol element in the response from " MACSTR,
  			   MAC2STR(sa));
  		return 0;
  	}
  
  	if (*pos != WLAN_EID_ADV_PROTO) {
  		wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
  			   "Protocol element ID %u in response from " MACSTR,
  			   *pos, MAC2STR(sa));
  		return 0;
  	}
  
  	adv_proto = pos;
  	pos += 2 + pos[1];
  
  	/* Query Response Length */
  	if (pos + 2 > data + len) {
  		wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
  		return 0;
  	}
  	resp_len = WPA_GET_LE16(pos);
  	pos += 2;
  
  	left = data + len - pos;
  	if (resp_len > left) {
  		wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
  			   "response from " MACSTR, MAC2STR(sa));
  		return 0;
  	}
  
  	if (resp_len < left) {
  		wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
  			   "after Query Response from " MACSTR,
  			   left - resp_len, MAC2STR(sa));
  	}
  
  	if (action == WLAN_PA_GAS_COMEBACK_RESP)
  		gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
  				      frag_id, more_frags, comeback_delay);
  	else
  		gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
  				     comeback_delay);
  
  	return 0;
  }
  
  
  static void gas_query_timeout(void *eloop_data, void *user_ctx)
  {
  	struct gas_query *gas = eloop_data;
  	struct gas_query_pending *query = user_ctx;
  
  	wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
  		   " dialog token %u",
  		   MAC2STR(query->addr), query->dialog_token);
  	gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
  }
  
  
  static int gas_query_dialog_token_available(struct gas_query *gas,
  					    const u8 *dst, u8 dialog_token)
  {
  	struct gas_query_pending *q;
  	dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
  		if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
  		    dialog_token == q->dialog_token)
  			return 0;
  	}
  
  	return 1;
  }
  
  
  static void gas_query_start_cb(struct wpa_radio_work *work, int deinit)
  {
  	struct gas_query_pending *query = work->ctx;
  	struct gas_query *gas = query->gas;
  	struct wpa_supplicant *wpa_s = gas->wpa_s;
  
  	if (deinit) {
  		if (work->started) {
  			gas->work = NULL;
  			gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
  			return;
  		}
  
  		gas_query_free(query, 1);
  		return;
  	}
  
  	if (wpas_update_random_addr_disassoc(wpa_s) < 0) {
  		wpa_msg(wpa_s, MSG_INFO,
  			"Failed to assign random MAC address for GAS");
  		gas_query_free(query, 1);
  		radio_work_done(work);
  		return;
  	}
  
  	gas->work = work;
  	gas_query_tx_initial_req(gas, query);
  }
  
  
  static void gas_query_tx_initial_req(struct gas_query *gas,
  				     struct gas_query_pending *query)
  {
  	if (gas_query_tx(gas, query, query->req,
  			 GAS_QUERY_WAIT_TIME_INITIAL) < 0) {
  		wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
  			   MACSTR, MAC2STR(query->addr));
  		gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  		return;
  	}
  	gas->current = query;
  
  	wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
  		   query->dialog_token);
  	eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
  			       gas_query_timeout, gas, query);
  }
  
  
  static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst)
  {
  	static int next_start = 0;
  	int dialog_token;
  
  	for (dialog_token = 0; dialog_token < 256; dialog_token++) {
  		if (gas_query_dialog_token_available(
  			    gas, dst, (next_start + dialog_token) % 256))
  			break;
  	}
  	if (dialog_token == 256)
  		return -1; /* Too many pending queries */
  	dialog_token = (next_start + dialog_token) % 256;
  	next_start = (dialog_token + 1) % 256;
  	return dialog_token;
  }
  
  
  static int gas_query_set_sa(struct gas_query *gas,
  			    struct gas_query_pending *query)
  {
  	struct wpa_supplicant *wpa_s = gas->wpa_s;
  	struct os_reltime now;
  
  	if (!wpa_s->conf->gas_rand_mac_addr ||
  	    !(wpa_s->current_bss ?
  	      (wpa_s->drv_flags &
  	       WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA_CONNECTED) :
  	      (wpa_s->drv_flags & WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA))) {
  		/* Use own MAC address as the transmitter address */
  		os_memcpy(query->sa, wpa_s->own_addr, ETH_ALEN);
  		return 0;
  	}
  
  	os_get_reltime(&now);
  
  	if (wpa_s->conf->gas_rand_mac_addr == gas->last_rand_sa_type &&
  	    gas->last_mac_addr_rand.sec != 0 &&
  	    !os_reltime_expired(&now, &gas->last_mac_addr_rand,
  				wpa_s->conf->gas_rand_addr_lifetime)) {
  		wpa_printf(MSG_DEBUG,
  			   "GAS: Use the previously selected random transmitter address "
  			   MACSTR, MAC2STR(gas->rand_addr));
  		os_memcpy(query->sa, gas->rand_addr, ETH_ALEN);
  		return 0;
  	}
  
  	if (wpa_s->conf->gas_rand_mac_addr == 1 &&
  	    random_mac_addr(gas->rand_addr) < 0) {
  		wpa_printf(MSG_ERROR, "GAS: Failed to get random address");
  		return -1;
  	}
  
  	if (wpa_s->conf->gas_rand_mac_addr == 2 &&
  	    random_mac_addr_keep_oui(gas->rand_addr) < 0) {
  		wpa_printf(MSG_ERROR,
  			   "GAS: Failed to get random address with same OUI");
  		return -1;
  	}
  
  	wpa_printf(MSG_DEBUG, "GAS: Use a new random transmitter address "
  		   MACSTR, MAC2STR(gas->rand_addr));
  	os_memcpy(query->sa, gas->rand_addr, ETH_ALEN);
  	os_get_reltime(&gas->last_mac_addr_rand);
  	gas->last_rand_sa_type = wpa_s->conf->gas_rand_mac_addr;
  
  	return 0;
  }
  
  
  /**
   * gas_query_req - Request a GAS query
   * @gas: GAS query data from gas_query_init()
   * @dst: Destination MAC address for the query
   * @freq: Frequency (in MHz) for the channel on which to send the query
   * @req: GAS query payload (to be freed by gas_query module in case of success
   *	return)
   * @cb: Callback function for reporting GAS query result and response
   * @ctx: Context pointer to use with the @cb call
   * Returns: dialog token (>= 0) on success or -1 on failure
   */
  int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
  		  struct wpabuf *req,
  		  void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
  			     enum gas_query_result result,
  			     const struct wpabuf *adv_proto,
  			     const struct wpabuf *resp, u16 status_code),
  		  void *ctx)
  {
  	struct gas_query_pending *query;
  	int dialog_token;
  
  	if (wpabuf_len(req) < 3)
  		return -1;
  
  	dialog_token = gas_query_new_dialog_token(gas, dst);
  	if (dialog_token < 0)
  		return -1;
  
  	query = os_zalloc(sizeof(*query));
  	if (query == NULL)
  		return -1;
  
  	query->gas = gas;
  	if (gas_query_set_sa(gas, query)) {
  		os_free(query);
  		return -1;
  	}
  	os_memcpy(query->addr, dst, ETH_ALEN);
  	query->dialog_token = dialog_token;
  	query->freq = freq;
  	query->cb = cb;
  	query->ctx = ctx;
  	query->req = req;
  	dl_list_add(&gas->pending, &query->list);
  
  	*(wpabuf_mhead_u8(req) + 2) = dialog_token;
  
  	wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
  		" dialog_token=%u freq=%d",
  		MAC2STR(query->addr), query->dialog_token, query->freq);
  
  	if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
  			   query) < 0) {
  		query->req = NULL; /* caller will free this in error case */
  		gas_query_free(query, 1);
  		return -1;
  	}
  
  	return dialog_token;
  }
  
  
  int gas_query_stop(struct gas_query *gas, u8 dialog_token)
  {
  	struct gas_query_pending *query;
  
  	dl_list_for_each(query, &gas->pending, struct gas_query_pending, list) {
  		if (query->dialog_token == dialog_token) {
  			if (!gas->work) {
  				/* The pending radio work has not yet been
  				 * started, but the pending entry has a
  				 * reference to the soon to be freed query.
  				 * Need to remove that radio work now to avoid
  				 * leaving behind a reference to freed memory.
  				 */
  				radio_remove_pending_work(gas->wpa_s, query);
  			}
  			gas_query_done(gas, query, GAS_QUERY_STOPPED);
  			return 0;
  		}
  	}
  
  	return -1;
  }
  