wpa_supplicant/gas_query.c

   1 /*
   2  * Generic advertisement service (GAS) query
   3  * Copyright (c) 2009, Atheros Communications
   4  * Copyright (c) 2011-2013, 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 "wpa_supplicant_i.h"
  19 #include "driver_i.h"
  20 #include "offchannel.h"
  21 #include "gas_query.h"
  22
  23
  24 /** GAS query timeout in seconds */
  25 #define GAS_QUERY_TIMEOUT_PERIOD 2
  26 /** Retry period for GAS query requests in milliseconds */
  27 #define GAS_SERVICE_RETRY_PERIOD_MS 500
  28
  29
  30 /**
  31  * struct gas_query_pending - Pending GAS query
  32  */
  33 struct gas_query_pending {
  34         struct dl_list list;
  35         struct gas_query *gas;
  36         u8 addr[ETH_ALEN];
  37         u8 dialog_token;
  38         u8 next_frag_id;
  39         unsigned int wait_comeback:1;
  40         unsigned int offchannel_tx_started:1;
  41         int freq;
  42         u16 status_code;
  43         struct wpabuf *req;
  44         struct wpabuf *adv_proto;
  45         struct wpabuf *resp;
  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 static void gas_service_timeout(void *eloop_data, void *user_ctx);
  67
  68
  69 /**
  70  * gas_query_init - Initialize GAS query component
  71  * @wpa_s: Pointer to wpa_supplicant data
  72  * Returns: Pointer to GAS query data or %NULL on failure
  73  */
  74 struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
  75 {
  76         struct gas_query *gas;
  77
  78         gas = os_zalloc(sizeof(*gas));
  79         if (gas == NULL)
  80                 return NULL;
  81
  82         gas->wpa_s = wpa_s;
  83         dl_list_init(&gas->pending);
  84
  85         return gas;
  86 }
  87
  88
  89 static const char * gas_result_txt(enum gas_query_result result)
  90 {
  91         switch (result) {
  92         case GAS_QUERY_SUCCESS:
  93                 return "SUCCESS";
  94         case GAS_QUERY_FAILURE:
  95                 return "FAILURE";
  96         case GAS_QUERY_TIMEOUT:
  97                 return "TIMEOUT";
  98         case GAS_QUERY_PEER_ERROR:
  99                 return "PEER_ERROR";
 100         case GAS_QUERY_INTERNAL_ERROR:
 101                 return "INTERNAL_ERROR";
 102         case GAS_QUERY_CANCELLED:
 103                 return "CANCELLED";
 104         case GAS_QUERY_DELETED_AT_DEINIT:
 105                 return "DELETED_AT_DEINIT";
 106         }
 107
 108         return "N/A";
 109 }
 110
 111
 112 static void gas_query_free(struct gas_query_pending *query, int del_list)
 113 {
 114         struct gas_query *gas = query->gas;
 115
 116         if (del_list)
 117                 dl_list_del(&query->list);
 118
 119         if (gas->work && gas->work->ctx == query) {
 120                 radio_work_done(gas->work);
 121                 gas->work = NULL;
 122         }
 123
 124         wpabuf_free(query->req);
 125         wpabuf_free(query->adv_proto);
 126         wpabuf_free(query->resp);
 127         os_free(query);
 128 }
 129
 130
 131 static void gas_query_done(struct gas_query *gas,
 132                            struct gas_query_pending *query,
 133                            enum gas_query_result result)
 134 {
 135         wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_DONE "addr=" MACSTR
 136                 " dialog_token=%u freq=%d status_code=%u result=%s",
 137                 MAC2STR(query->addr), query->dialog_token, query->freq,
 138                 query->status_code, gas_result_txt(result));
 139         if (gas->current == query)
 140                 gas->current = NULL;
 141         if (query->offchannel_tx_started)
 142                 offchannel_send_action_done(gas->wpa_s);
 143         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 144         eloop_cancel_timeout(gas_query_timeout, gas, query);
 145         eloop_cancel_timeout(gas_service_timeout, gas, query);
 146         dl_list_del(&query->list);
 147         query->cb(query->ctx, query->addr, query->dialog_token, result,
 148                   query->adv_proto, query->resp, query->status_code);
 149         gas_query_free(query, 0);
 150 }
 151
 152
 153 /**
 154  * gas_query_deinit - Deinitialize GAS query component
 155  * @gas: GAS query data from gas_query_init()
 156  */
 157 void gas_query_deinit(struct gas_query *gas)
 158 {
 159         struct gas_query_pending *query, *next;
 160
 161         if (gas == NULL)
 162                 return;
 163
 164         dl_list_for_each_safe(query, next, &gas->pending,
 165                               struct gas_query_pending, list)
 166                 gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
 167
 168         os_free(gas);
 169 }
 170
 171
 172 static struct gas_query_pending *
 173 gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
 174 {
 175         struct gas_query_pending *q;
 176         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 177                 if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
 178                     q->dialog_token == dialog_token)
 179                         return q;
 180         }
 181         return NULL;
 182 }
 183
 184
 185 static int gas_query_append(struct gas_query_pending *query, const u8 *data,
 186                             size_t len)
 187 {
 188         if (wpabuf_resize(&query->resp, len) < 0) {
 189                 wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
 190                 return -1;
 191         }
 192         wpabuf_put_data(query->resp, data, len);
 193         return 0;
 194 }
 195
 196
 197 static void gas_query_tx_status(struct wpa_supplicant *wpa_s,
 198                                 unsigned int freq, const u8 *dst,
 199                                 const u8 *src, const u8 *bssid,
 200                                 const u8 *data, size_t data_len,
 201                                 enum offchannel_send_action_result result)
 202 {
 203         struct gas_query_pending *query;
 204         struct gas_query *gas = wpa_s->gas;
 205
 206         if (gas->current == NULL) {
 207                 wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
 208                            MACSTR " result=%d - no query in progress",
 209                            freq, MAC2STR(dst), result);
 210                 return;
 211         }
 212
 213         query = gas->current;
 214
 215         wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
 216                    " result=%d query=%p dialog_token=%u",
 217                    freq, MAC2STR(dst), result, query, query->dialog_token);
 218         if (os_memcmp(dst, query->addr, ETH_ALEN) != 0) {
 219                 wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
 220                 return;
 221         }
 222
 223         if (result == OFFCHANNEL_SEND_ACTION_SUCCESS) {
 224                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 225                 eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 226                                        gas_query_timeout, gas, query);
 227         }
 228         if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
 229                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 230                 eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
 231         }
 232 }
 233
 234
 235 static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
 236                         struct wpabuf *req)
 237 {
 238         int res;
 239         wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
 240                    "freq=%d", MAC2STR(query->addr),
 241                    (unsigned int) wpabuf_len(req), query->freq);
 242         res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
 243                                      gas->wpa_s->own_addr, query->addr,
 244                                      wpabuf_head(req), wpabuf_len(req), 1000,
 245                                      gas_query_tx_status, 0);
 246         if (res == 0)
 247                 query->offchannel_tx_started = 1;
 248         return res;
 249 }
 250
 251
 252 static void gas_query_tx_comeback_req(struct gas_query *gas,
 253                                       struct gas_query_pending *query)
 254 {
 255         struct wpabuf *req;
 256
 257         req = gas_build_comeback_req(query->dialog_token);
 258         if (req == NULL) {
 259                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 260                 return;
 261         }
 262
 263         if (gas_query_tx(gas, query, req) < 0) {
 264                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 265                            MACSTR, MAC2STR(query->addr));
 266                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 267         }
 268
 269         wpabuf_free(req);
 270 }
 271
 272
 273 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
 274 {
 275         struct gas_query *gas = eloop_data;
 276         struct gas_query_pending *query = user_ctx;
 277
 278         wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
 279                    MAC2STR(query->addr));
 280         gas_query_tx_comeback_req(gas, query);
 281 }
 282
 283
 284 static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
 285                                             struct gas_query_pending *query,
 286                                             u16 comeback_delay)
 287 {
 288         unsigned int secs, usecs;
 289
 290         secs = (comeback_delay * 1024) / 1000000;
 291         usecs = comeback_delay * 1024 - secs * 1000000;
 292         wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
 293                    " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
 294         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 295         eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
 296                                gas, query);
 297 }
 298
 299
 300 static void gas_query_rx_initial(struct gas_query *gas,
 301                                  struct gas_query_pending *query,
 302                                  const u8 *adv_proto, const u8 *resp,
 303                                  size_t len, u16 comeback_delay)
 304 {
 305         wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
 306                    MACSTR " (dialog_token=%u comeback_delay=%u)",
 307                    MAC2STR(query->addr), query->dialog_token, comeback_delay);
 308
 309         query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
 310         if (query->adv_proto == NULL) {
 311                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 312                 return;
 313         }
 314
 315         if (comeback_delay) {
 316                 query->wait_comeback = 1;
 317                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 318                 return;
 319         }
 320
 321         /* Query was completed without comeback mechanism */
 322         if (gas_query_append(query, resp, len) < 0) {
 323                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 324                 return;
 325         }
 326
 327         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 328 }
 329
 330
 331 static void gas_query_rx_comeback(struct gas_query *gas,
 332                                   struct gas_query_pending *query,
 333                                   const u8 *adv_proto, const u8 *resp,
 334                                   size_t len, u8 frag_id, u8 more_frags,
 335                                   u16 comeback_delay)
 336 {
 337         wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
 338                    MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
 339                    "comeback_delay=%u)",
 340                    MAC2STR(query->addr), query->dialog_token, frag_id,
 341                    more_frags, comeback_delay);
 342
 343         if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
 344             os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
 345                       wpabuf_len(query->adv_proto)) != 0) {
 346                 wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
 347                            "between initial and comeback response from "
 348                            MACSTR, MAC2STR(query->addr));
 349                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 350                 return;
 351         }
 352
 353         if (comeback_delay) {
 354                 if (frag_id) {
 355                         wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
 356                                    "with non-zero frag_id and comeback_delay "
 357                                    "from " MACSTR, MAC2STR(query->addr));
 358                         gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 359                         return;
 360                 }
 361                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 362                 return;
 363         }
 364
 365         if (frag_id != query->next_frag_id) {
 366                 wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
 367                            "from " MACSTR, MAC2STR(query->addr));
 368                 if (frag_id + 1 == query->next_frag_id) {
 369                         wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
 370                                    "retry of previous fragment");
 371                         return;
 372                 }
 373                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 374                 return;
 375         }
 376         query->next_frag_id++;
 377
 378         if (gas_query_append(query, resp, len) < 0) {
 379                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 380                 return;
 381         }
 382
 383         if (more_frags) {
 384                 gas_query_tx_comeback_req(gas, query);
 385                 return;
 386         }
 387
 388         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 389 }
 390
 391
 392 /**
 393  * gas_query_rx - Indicate reception of a Public Action frame
 394  * @gas: GAS query data from gas_query_init()
 395  * @da: Destination MAC address of the Action frame
 396  * @sa: Source MAC address of the Action frame
 397  * @bssid: BSSID of the Action frame
 398  * @data: Payload of the Action frame
 399  * @len: Length of @data
 400  * @freq: Frequency (in MHz) on which the frame was received
 401  * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
 402  */
 403 int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
 404                  const u8 *bssid, const u8 *data, size_t len, int freq)
 405 {
 406         struct gas_query_pending *query;
 407         u8 action, dialog_token, frag_id = 0, more_frags = 0;
 408         u16 comeback_delay, resp_len;
 409         const u8 *pos, *adv_proto;
 410
 411         if (gas == NULL || len < 4)
 412                 return -1;
 413
 414         pos = data;
 415         action = *pos++;
 416         dialog_token = *pos++;
 417
 418         if (action != WLAN_PA_GAS_INITIAL_RESP &&
 419             action != WLAN_PA_GAS_COMEBACK_RESP)
 420                 return -1; /* Not a GAS response */
 421
 422         query = gas_query_get_pending(gas, sa, dialog_token);
 423         if (query == NULL) {
 424                 wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
 425                            " dialog token %u", MAC2STR(sa), dialog_token);
 426                 return -1;
 427         }
 428
 429         if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
 430                 wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
 431                            MACSTR " dialog token %u when waiting for comeback "
 432                            "response", MAC2STR(sa), dialog_token);
 433                 return 0;
 434         }
 435
 436         if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
 437                 wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
 438                            MACSTR " dialog token %u when waiting for initial "
 439                            "response", MAC2STR(sa), dialog_token);
 440                 return 0;
 441         }
 442
 443         query->status_code = WPA_GET_LE16(pos);
 444         pos += 2;
 445
 446         if (query->status_code != WLAN_STATUS_SUCCESS) {
 447                 wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
 448                            "%u failed - status code %u",
 449                            MAC2STR(sa), dialog_token, query->status_code);
 450                 gas_query_done(gas, query, GAS_QUERY_FAILURE);
 451                 return 0;
 452         }
 453
 454         if (action == WLAN_PA_GAS_COMEBACK_RESP) {
 455                 if (pos + 1 > data + len)
 456                         return 0;
 457                 frag_id = *pos & 0x7f;
 458                 more_frags = (*pos & 0x80) >> 7;
 459                 pos++;
 460         }
 461
 462         /* Comeback Delay */
 463         if (pos + 2 > data + len)
 464                 return 0;
 465         comeback_delay = WPA_GET_LE16(pos);
 466         pos += 2;
 467
 468         /* Advertisement Protocol element */
 469         if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
 470                 wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
 471                            "Protocol element in the response from " MACSTR,
 472                            MAC2STR(sa));
 473                 return 0;
 474         }
 475
 476         if (*pos != WLAN_EID_ADV_PROTO) {
 477                 wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
 478                            "Protocol element ID %u in response from " MACSTR,
 479                            *pos, MAC2STR(sa));
 480                 return 0;
 481         }
 482
 483         adv_proto = pos;
 484         pos += 2 + pos[1];
 485
 486         /* Query Response Length */
 487         if (pos + 2 > data + len) {
 488                 wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
 489                 return 0;
 490         }
 491         resp_len = WPA_GET_LE16(pos);
 492         pos += 2;
 493
 494         if (pos + resp_len > data + len) {
 495                 wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
 496                            "response from " MACSTR, MAC2STR(sa));
 497                 return 0;
 498         }
 499
 500         if (pos + resp_len < data + len) {
 501                 wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
 502                            "after Query Response from " MACSTR,
 503                            (unsigned int) (data + len - pos - resp_len),
 504                            MAC2STR(sa));
 505         }
 506
 507         if (action == WLAN_PA_GAS_COMEBACK_RESP)
 508                 gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
 509                                       frag_id, more_frags, comeback_delay);
 510         else
 511                 gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
 512                                      comeback_delay);
 513
 514         return 0;
 515 }
 516
 517
 518 static void gas_query_timeout(void *eloop_data, void *user_ctx)
 519 {
 520         struct gas_query *gas = eloop_data;
 521         struct gas_query_pending *query = user_ctx;
 522
 523         wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
 524                    " dialog token %u",
 525                    MAC2STR(query->addr), query->dialog_token);
 526         gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
 527 }
 528
 529
 530 static void gas_service_timeout(void *eloop_data, void *user_ctx)
 531 {
 532         struct gas_query *gas = eloop_data;
 533         struct wpa_supplicant *wpa_s = gas->wpa_s;
 534         struct gas_query_pending *query = user_ctx;
 535         int conn;
 536
 537         conn = wpas_wpa_is_in_progress(wpa_s, 1);
 538         if (conn) {
 539                 wpa_printf(MSG_DEBUG, "GAS: Delaying GAS query Tx while connection operation is in progress");
 540                 eloop_register_timeout(
 541                         GAS_SERVICE_RETRY_PERIOD_MS / 1000,
 542                         (GAS_SERVICE_RETRY_PERIOD_MS % 1000) * 1000,
 543                         gas_service_timeout, gas, query);
 544                 return;
 545         }
 546
 547         if (gas_query_tx(gas, query, query->req) < 0) {
 548                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 549                            MACSTR, MAC2STR(query->addr));
 550                 gas_query_free(query, 1);
 551                 return;
 552         }
 553         gas->current = query;
 554
 555         wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
 556                    query->dialog_token);
 557         eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 558                                gas_query_timeout, gas, query);
 559 }
 560
 561
 562 static int gas_query_dialog_token_available(struct gas_query *gas,
 563                                             const u8 *dst, u8 dialog_token)
 564 {
 565         struct gas_query_pending *q;
 566         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 567                 if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
 568                     dialog_token == q->dialog_token)
 569                         return 0;
 570         }
 571
 572         return 1;
 573 }
 574
 575
 576 static void gas_query_start_cb(struct wpa_radio_work *work, int deinit)
 577 {
 578         struct gas_query_pending *query = work->ctx;
 579
 580         if (deinit) {
 581                 gas_query_free(query, 1);
 582                 return;
 583         }
 584
 585         query->gas->work = work;
 586         gas_service_timeout(query->gas, query);
 587 }
 588
 589
 590 /**
 591  * gas_query_req - Request a GAS query
 592  * @gas: GAS query data from gas_query_init()
 593  * @dst: Destination MAC address for the query
 594  * @freq: Frequency (in MHz) for the channel on which to send the query
 595  * @req: GAS query payload (to be freed by gas_query module in case of success
 596  *      return)
 597  * @cb: Callback function for reporting GAS query result and response
 598  * @ctx: Context pointer to use with the @cb call
 599  * Returns: dialog token (>= 0) on success or -1 on failure
 600  */
 601 int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
 602                   struct wpabuf *req,
 603                   void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
 604                              enum gas_query_result result,
 605                              const struct wpabuf *adv_proto,
 606                              const struct wpabuf *resp, u16 status_code),
 607                   void *ctx)
 608 {
 609         struct gas_query_pending *query;
 610         int dialog_token;
 611         static int next_start = 0;
 612
 613         if (wpabuf_len(req) < 3)
 614                 return -1;
 615
 616         for (dialog_token = 0; dialog_token < 256; dialog_token++) {
 617                 if (gas_query_dialog_token_available(
 618                             gas, dst, (next_start + dialog_token) % 256))
 619                         break;
 620         }
 621         if (dialog_token == 256)
 622                 return -1; /* Too many pending queries */
 623         dialog_token = (next_start + dialog_token) % 256;
 624         next_start = (dialog_token + 1) % 256;
 625
 626         query = os_zalloc(sizeof(*query));
 627         if (query == NULL)
 628                 return -1;
 629
 630         query->gas = gas;
 631         os_memcpy(query->addr, dst, ETH_ALEN);
 632         query->dialog_token = dialog_token;
 633         query->freq = freq;
 634         query->cb = cb;
 635         query->ctx = ctx;
 636         query->req = req;
 637         dl_list_add(&gas->pending, &query->list);
 638
 639         *(wpabuf_mhead_u8(req) + 2) = dialog_token;
 640
 641         wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
 642                 " dialog_token=%u freq=%d",
 643                 MAC2STR(query->addr), query->dialog_token, query->freq);
 644
 645         if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
 646                            query) < 0) {
 647                 gas_query_free(query, 1);
 648                 return -1;
 649         }
 650
 651         return dialog_token;
 652 }
 653
 654
 655 /**
 656  * gas_query_cancel - Cancel a pending GAS query
 657  * @gas: GAS query data from gas_query_init()
 658  * @dst: Destination MAC address for the query
 659  * @dialog_token: Dialog token from gas_query_req()
 660  */
 661 void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
 662 {
 663         struct gas_query_pending *query;
 664
 665         query = gas_query_get_pending(gas, dst, dialog_token);
 666         if (query)
 667                 gas_query_done(gas, query, GAS_QUERY_CANCELLED);
 668
 669 }