wpa_supplicant/gas_query.c

   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 "config.h"
  21 #include "driver_i.h"
  22 #include "offchannel.h"
  23 #include "gas_query.h"
  24
  25
  26 /** GAS query timeout in seconds */
  27 #define GAS_QUERY_TIMEOUT_PERIOD 2
  28
  29 /* GAS query wait-time / duration in ms */
  30 #define GAS_QUERY_WAIT_TIME_INITIAL 1000
  31 #define GAS_QUERY_WAIT_TIME_COMEBACK 150
  32
  33 /**
  34  * struct gas_query_pending - Pending GAS query
  35  */
  36 struct gas_query_pending {
  37         struct dl_list list;
  38         struct gas_query *gas;
  39         u8 addr[ETH_ALEN];
  40         u8 dialog_token;
  41         u8 next_frag_id;
  42         unsigned int wait_comeback:1;
  43         unsigned int offchannel_tx_started:1;
  44         unsigned int retry:1;
  45         int freq;
  46         u16 status_code;
  47         struct wpabuf *req;
  48         struct wpabuf *adv_proto;
  49         struct wpabuf *resp;
  50         struct os_reltime last_oper;
  51         void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
  52                    enum gas_query_result result,
  53                    const struct wpabuf *adv_proto,
  54                    const struct wpabuf *resp, u16 status_code);
  55         void *ctx;
  56 };
  57
  58 /**
  59  * struct gas_query - Internal GAS query data
  60  */
  61 struct gas_query {
  62         struct wpa_supplicant *wpa_s;
  63         struct dl_list pending; /* struct gas_query_pending */
  64         struct gas_query_pending *current;
  65         struct wpa_radio_work *work;
  66 };
  67
  68
  69 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
  70 static void gas_query_timeout(void *eloop_data, void *user_ctx);
  71 static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx);
  72 static void gas_query_tx_initial_req(struct gas_query *gas,
  73                                      struct gas_query_pending *query);
  74 static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst);
  75
  76
  77 static int ms_from_time(struct os_reltime *last)
  78 {
  79         struct os_reltime now, res;
  80
  81         os_get_reltime(&now);
  82         os_reltime_sub(&now, last, &res);
  83         return res.sec * 1000 + res.usec / 1000;
  84 }
  85
  86
  87 /**
  88  * gas_query_init - Initialize GAS query component
  89  * @wpa_s: Pointer to wpa_supplicant data
  90  * Returns: Pointer to GAS query data or %NULL on failure
  91  */
  92 struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
  93 {
  94         struct gas_query *gas;
  95
  96         gas = os_zalloc(sizeof(*gas));
  97         if (gas == NULL)
  98                 return NULL;
  99
 100         gas->wpa_s = wpa_s;
 101         dl_list_init(&gas->pending);
 102
 103         return gas;
 104 }
 105
 106
 107 static const char * gas_result_txt(enum gas_query_result result)
 108 {
 109         switch (result) {
 110         case GAS_QUERY_SUCCESS:
 111                 return "SUCCESS";
 112         case GAS_QUERY_FAILURE:
 113                 return "FAILURE";
 114         case GAS_QUERY_TIMEOUT:
 115                 return "TIMEOUT";
 116         case GAS_QUERY_PEER_ERROR:
 117                 return "PEER_ERROR";
 118         case GAS_QUERY_INTERNAL_ERROR:
 119                 return "INTERNAL_ERROR";
 120         case GAS_QUERY_DELETED_AT_DEINIT:
 121                 return "DELETED_AT_DEINIT";
 122         }
 123
 124         return "N/A";
 125 }
 126
 127
 128 static void gas_query_free(struct gas_query_pending *query, int del_list)
 129 {
 130         struct gas_query *gas = query->gas;
 131
 132         if (del_list)
 133                 dl_list_del(&query->list);
 134
 135         if (gas->work && gas->work->ctx == query) {
 136                 radio_work_done(gas->work);
 137                 gas->work = NULL;
 138         }
 139
 140         wpabuf_free(query->req);
 141         wpabuf_free(query->adv_proto);
 142         wpabuf_free(query->resp);
 143         os_free(query);
 144 }
 145
 146
 147 static void gas_query_done(struct gas_query *gas,
 148                            struct gas_query_pending *query,
 149                            enum gas_query_result result)
 150 {
 151         wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_DONE "addr=" MACSTR
 152                 " dialog_token=%u freq=%d status_code=%u result=%s",
 153                 MAC2STR(query->addr), query->dialog_token, query->freq,
 154                 query->status_code, gas_result_txt(result));
 155         if (gas->current == query)
 156                 gas->current = NULL;
 157         if (query->offchannel_tx_started)
 158                 offchannel_send_action_done(gas->wpa_s);
 159         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 160         eloop_cancel_timeout(gas_query_timeout, gas, query);
 161         eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);
 162         dl_list_del(&query->list);
 163         query->cb(query->ctx, query->addr, query->dialog_token, result,
 164                   query->adv_proto, query->resp, query->status_code);
 165         gas_query_free(query, 0);
 166 }
 167
 168
 169 /**
 170  * gas_query_deinit - Deinitialize GAS query component
 171  * @gas: GAS query data from gas_query_init()
 172  */
 173 void gas_query_deinit(struct gas_query *gas)
 174 {
 175         struct gas_query_pending *query, *next;
 176
 177         if (gas == NULL)
 178                 return;
 179
 180         dl_list_for_each_safe(query, next, &gas->pending,
 181                               struct gas_query_pending, list)
 182                 gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
 183
 184         os_free(gas);
 185 }
 186
 187
 188 static struct gas_query_pending *
 189 gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
 190 {
 191         struct gas_query_pending *q;
 192         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 193                 if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
 194                     q->dialog_token == dialog_token)
 195                         return q;
 196         }
 197         return NULL;
 198 }
 199
 200
 201 static int gas_query_append(struct gas_query_pending *query, const u8 *data,
 202                             size_t len)
 203 {
 204         if (wpabuf_resize(&query->resp, len) < 0) {
 205                 wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
 206                 return -1;
 207         }
 208         wpabuf_put_data(query->resp, data, len);
 209         return 0;
 210 }
 211
 212
 213 static void gas_query_tx_status(struct wpa_supplicant *wpa_s,
 214                                 unsigned int freq, const u8 *dst,
 215                                 const u8 *src, const u8 *bssid,
 216                                 const u8 *data, size_t data_len,
 217                                 enum offchannel_send_action_result result)
 218 {
 219         struct gas_query_pending *query;
 220         struct gas_query *gas = wpa_s->gas;
 221         int dur;
 222
 223         if (gas->current == NULL) {
 224                 wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
 225                            MACSTR " result=%d - no query in progress",
 226                            freq, MAC2STR(dst), result);
 227                 return;
 228         }
 229
 230         query = gas->current;
 231
 232         dur = ms_from_time(&query->last_oper);
 233         wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
 234                    " result=%d query=%p dialog_token=%u dur=%d ms",
 235                    freq, MAC2STR(dst), result, query, query->dialog_token, dur);
 236         if (os_memcmp(dst, query->addr, ETH_ALEN) != 0) {
 237                 wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
 238                 return;
 239         }
 240         os_get_reltime(&query->last_oper);
 241
 242         if (result == OFFCHANNEL_SEND_ACTION_SUCCESS) {
 243                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 244                 eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 245                                        gas_query_timeout, gas, query);
 246                 if (query->wait_comeback && !query->retry) {
 247                         eloop_cancel_timeout(gas_query_rx_comeback_timeout,
 248                                              gas, query);
 249                         eloop_register_timeout(
 250                                 0, (GAS_QUERY_WAIT_TIME_COMEBACK + 10) * 1000,
 251                                 gas_query_rx_comeback_timeout, gas, query);
 252                 }
 253         }
 254         if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
 255                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 256                 eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
 257         }
 258 }
 259
 260
 261 static int pmf_in_use(struct wpa_supplicant *wpa_s, const u8 *addr)
 262 {
 263         if (wpa_s->current_ssid == NULL ||
 264             wpa_s->wpa_state < WPA_4WAY_HANDSHAKE ||
 265             os_memcmp(addr, wpa_s->bssid, ETH_ALEN) != 0)
 266                 return 0;
 267         return wpa_sm_pmf_enabled(wpa_s->wpa);
 268 }
 269
 270
 271 static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
 272                         struct wpabuf *req, unsigned int wait_time)
 273 {
 274         int res, prot = pmf_in_use(gas->wpa_s, query->addr);
 275         const u8 *bssid;
 276         const u8 wildcard_bssid[ETH_ALEN] = {
 277                 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
 278         };
 279
 280         wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
 281                    "freq=%d prot=%d", MAC2STR(query->addr),
 282                    (unsigned int) wpabuf_len(req), query->freq, prot);
 283         if (prot) {
 284                 u8 *categ = wpabuf_mhead_u8(req);
 285                 *categ = WLAN_ACTION_PROTECTED_DUAL;
 286         }
 287         os_get_reltime(&query->last_oper);
 288         if (gas->wpa_s->max_remain_on_chan &&
 289             wait_time > gas->wpa_s->max_remain_on_chan)
 290                 wait_time = gas->wpa_s->max_remain_on_chan;
 291         if (!gas->wpa_s->conf->gas_address3 ||
 292             (gas->wpa_s->current_ssid &&
 293              gas->wpa_s->wpa_state >= WPA_ASSOCIATED &&
 294              os_memcmp(query->addr, gas->wpa_s->bssid, ETH_ALEN) == 0))
 295                 bssid = query->addr;
 296         else
 297                 bssid = wildcard_bssid;
 298         res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
 299                                      gas->wpa_s->own_addr, bssid,
 300                                      wpabuf_head(req), wpabuf_len(req),
 301                                      wait_time, gas_query_tx_status, 0);
 302         if (res == 0)
 303                 query->offchannel_tx_started = 1;
 304         return res;
 305 }
 306
 307
 308 static void gas_query_tx_comeback_req(struct gas_query *gas,
 309                                       struct gas_query_pending *query)
 310 {
 311         struct wpabuf *req;
 312         unsigned int wait_time;
 313
 314         req = gas_build_comeback_req(query->dialog_token);
 315         if (req == NULL) {
 316                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 317                 return;
 318         }
 319
 320         wait_time = (query->retry || !query->offchannel_tx_started) ?
 321                 GAS_QUERY_WAIT_TIME_INITIAL : GAS_QUERY_WAIT_TIME_COMEBACK;
 322
 323         if (gas_query_tx(gas, query, req, wait_time) < 0) {
 324                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 325                            MACSTR, MAC2STR(query->addr));
 326                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 327         }
 328
 329         wpabuf_free(req);
 330 }
 331
 332
 333 static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx)
 334 {
 335         struct gas_query *gas = eloop_data;
 336         struct gas_query_pending *query = user_ctx;
 337         int dialog_token;
 338
 339         wpa_printf(MSG_DEBUG,
 340                    "GAS: No response to comeback request received (retry=%u)",
 341                    query->retry);
 342         if (gas->current != query || query->retry)
 343                 return;
 344         dialog_token = gas_query_new_dialog_token(gas, query->addr);
 345         if (dialog_token < 0)
 346                 return;
 347         wpa_printf(MSG_DEBUG,
 348                    "GAS: Retry GAS query due to comeback response timeout");
 349         query->retry = 1;
 350         query->dialog_token = dialog_token;
 351         *(wpabuf_mhead_u8(query->req) + 2) = dialog_token;
 352         query->wait_comeback = 0;
 353         query->next_frag_id = 0;
 354         wpabuf_free(query->adv_proto);
 355         query->adv_proto = NULL;
 356         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 357         eloop_cancel_timeout(gas_query_timeout, gas, query);
 358         gas_query_tx_initial_req(gas, query);
 359 }
 360
 361
 362 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
 363 {
 364         struct gas_query *gas = eloop_data;
 365         struct gas_query_pending *query = user_ctx;
 366
 367         wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
 368                    MAC2STR(query->addr));
 369         gas_query_tx_comeback_req(gas, query);
 370 }
 371
 372
 373 static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
 374                                             struct gas_query_pending *query,
 375                                             u16 comeback_delay)
 376 {
 377         unsigned int secs, usecs;
 378
 379         if (comeback_delay > 1 && query->offchannel_tx_started) {
 380                 offchannel_send_action_done(gas->wpa_s);
 381                 query->offchannel_tx_started = 0;
 382         }
 383
 384         secs = (comeback_delay * 1024) / 1000000;
 385         usecs = comeback_delay * 1024 - secs * 1000000;
 386         wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
 387                    " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
 388         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 389         eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
 390                                gas, query);
 391 }
 392
 393
 394 static void gas_query_rx_initial(struct gas_query *gas,
 395                                  struct gas_query_pending *query,
 396                                  const u8 *adv_proto, const u8 *resp,
 397                                  size_t len, u16 comeback_delay)
 398 {
 399         wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
 400                    MACSTR " (dialog_token=%u comeback_delay=%u)",
 401                    MAC2STR(query->addr), query->dialog_token, comeback_delay);
 402
 403         query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
 404         if (query->adv_proto == NULL) {
 405                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 406                 return;
 407         }
 408
 409         if (comeback_delay) {
 410                 query->wait_comeback = 1;
 411                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 412                 return;
 413         }
 414
 415         /* Query was completed without comeback mechanism */
 416         if (gas_query_append(query, resp, len) < 0) {
 417                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 418                 return;
 419         }
 420
 421         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 422 }
 423
 424
 425 static void gas_query_rx_comeback(struct gas_query *gas,
 426                                   struct gas_query_pending *query,
 427                                   const u8 *adv_proto, const u8 *resp,
 428                                   size_t len, u8 frag_id, u8 more_frags,
 429                                   u16 comeback_delay)
 430 {
 431         wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
 432                    MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
 433                    "comeback_delay=%u)",
 434                    MAC2STR(query->addr), query->dialog_token, frag_id,
 435                    more_frags, comeback_delay);
 436         eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);
 437
 438         if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
 439             os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
 440                       wpabuf_len(query->adv_proto)) != 0) {
 441                 wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
 442                            "between initial and comeback response from "
 443                            MACSTR, MAC2STR(query->addr));
 444                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 445                 return;
 446         }
 447
 448         if (comeback_delay) {
 449                 if (frag_id) {
 450                         wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
 451                                    "with non-zero frag_id and comeback_delay "
 452                                    "from " MACSTR, MAC2STR(query->addr));
 453                         gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 454                         return;
 455                 }
 456                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 457                 return;
 458         }
 459
 460         if (frag_id != query->next_frag_id) {
 461                 wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
 462                            "from " MACSTR, MAC2STR(query->addr));
 463                 if (frag_id + 1 == query->next_frag_id) {
 464                         wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
 465                                    "retry of previous fragment");
 466                         return;
 467                 }
 468                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 469                 return;
 470         }
 471         query->next_frag_id++;
 472
 473         if (gas_query_append(query, resp, len) < 0) {
 474                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 475                 return;
 476         }
 477
 478         if (more_frags) {
 479                 gas_query_tx_comeback_req(gas, query);
 480                 return;
 481         }
 482
 483         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 484 }
 485
 486
 487 /**
 488  * gas_query_rx - Indicate reception of a Public Action or Protected Dual frame
 489  * @gas: GAS query data from gas_query_init()
 490  * @da: Destination MAC address of the Action frame
 491  * @sa: Source MAC address of the Action frame
 492  * @bssid: BSSID of the Action frame
 493  * @categ: Category of the Action frame
 494  * @data: Payload of the Action frame
 495  * @len: Length of @data
 496  * @freq: Frequency (in MHz) on which the frame was received
 497  * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
 498  */
 499 int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
 500                  const u8 *bssid, u8 categ, const u8 *data, size_t len,
 501                  int freq)
 502 {
 503         struct gas_query_pending *query;
 504         u8 action, dialog_token, frag_id = 0, more_frags = 0;
 505         u16 comeback_delay, resp_len;
 506         const u8 *pos, *adv_proto;
 507         int prot, pmf;
 508         unsigned int left;
 509
 510         if (gas == NULL || len < 4)
 511                 return -1;
 512
 513         pos = data;
 514         action = *pos++;
 515         dialog_token = *pos++;
 516
 517         if (action != WLAN_PA_GAS_INITIAL_RESP &&
 518             action != WLAN_PA_GAS_COMEBACK_RESP)
 519                 return -1; /* Not a GAS response */
 520
 521         prot = categ == WLAN_ACTION_PROTECTED_DUAL;
 522         pmf = pmf_in_use(gas->wpa_s, sa);
 523         if (prot && !pmf) {
 524                 wpa_printf(MSG_DEBUG, "GAS: Drop unexpected protected GAS frame when PMF is disabled");
 525                 return 0;
 526         }
 527         if (!prot && pmf) {
 528                 wpa_printf(MSG_DEBUG, "GAS: Drop unexpected unprotected GAS frame when PMF is enabled");
 529                 return 0;
 530         }
 531
 532         query = gas_query_get_pending(gas, sa, dialog_token);
 533         if (query == NULL) {
 534                 wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
 535                            " dialog token %u", MAC2STR(sa), dialog_token);
 536                 return -1;
 537         }
 538
 539         wpa_printf(MSG_DEBUG, "GAS: Response in %d ms from " MACSTR,
 540                    ms_from_time(&query->last_oper), MAC2STR(sa));
 541
 542         if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
 543                 wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
 544                            MACSTR " dialog token %u when waiting for comeback "
 545                            "response", MAC2STR(sa), dialog_token);
 546                 return 0;
 547         }
 548
 549         if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
 550                 wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
 551                            MACSTR " dialog token %u when waiting for initial "
 552                            "response", MAC2STR(sa), dialog_token);
 553                 return 0;
 554         }
 555
 556         query->status_code = WPA_GET_LE16(pos);
 557         pos += 2;
 558
 559         if (query->status_code == WLAN_STATUS_QUERY_RESP_OUTSTANDING &&
 560             action == WLAN_PA_GAS_COMEBACK_RESP) {
 561                 wpa_printf(MSG_DEBUG, "GAS: Allow non-zero status for outstanding comeback response");
 562         } else if (query->status_code != WLAN_STATUS_SUCCESS) {
 563                 wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
 564                            "%u failed - status code %u",
 565                            MAC2STR(sa), dialog_token, query->status_code);
 566                 gas_query_done(gas, query, GAS_QUERY_FAILURE);
 567                 return 0;
 568         }
 569
 570         if (action == WLAN_PA_GAS_COMEBACK_RESP) {
 571                 if (pos + 1 > data + len)
 572                         return 0;
 573                 frag_id = *pos & 0x7f;
 574                 more_frags = (*pos & 0x80) >> 7;
 575                 pos++;
 576         }
 577
 578         /* Comeback Delay */
 579         if (pos + 2 > data + len)
 580                 return 0;
 581         comeback_delay = WPA_GET_LE16(pos);
 582         pos += 2;
 583
 584         /* Advertisement Protocol element */
 585         if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
 586                 wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
 587                            "Protocol element in the response from " MACSTR,
 588                            MAC2STR(sa));
 589                 return 0;
 590         }
 591
 592         if (*pos != WLAN_EID_ADV_PROTO) {
 593                 wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
 594                            "Protocol element ID %u in response from " MACSTR,
 595                            *pos, MAC2STR(sa));
 596                 return 0;
 597         }
 598
 599         adv_proto = pos;
 600         pos += 2 + pos[1];
 601
 602         /* Query Response Length */
 603         if (pos + 2 > data + len) {
 604                 wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
 605                 return 0;
 606         }
 607         resp_len = WPA_GET_LE16(pos);
 608         pos += 2;
 609
 610         left = data + len - pos;
 611         if (resp_len > left) {
 612                 wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
 613                            "response from " MACSTR, MAC2STR(sa));
 614                 return 0;
 615         }
 616
 617         if (resp_len < left) {
 618                 wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
 619                            "after Query Response from " MACSTR,
 620                            left - resp_len, MAC2STR(sa));
 621         }
 622
 623         if (action == WLAN_PA_GAS_COMEBACK_RESP)
 624                 gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
 625                                       frag_id, more_frags, comeback_delay);
 626         else
 627                 gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
 628                                      comeback_delay);
 629
 630         return 0;
 631 }
 632
 633
 634 static void gas_query_timeout(void *eloop_data, void *user_ctx)
 635 {
 636         struct gas_query *gas = eloop_data;
 637         struct gas_query_pending *query = user_ctx;
 638
 639         wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
 640                    " dialog token %u",
 641                    MAC2STR(query->addr), query->dialog_token);
 642         gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
 643 }
 644
 645
 646 static int gas_query_dialog_token_available(struct gas_query *gas,
 647                                             const u8 *dst, u8 dialog_token)
 648 {
 649         struct gas_query_pending *q;
 650         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 651                 if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
 652                     dialog_token == q->dialog_token)
 653                         return 0;
 654         }
 655
 656         return 1;
 657 }
 658
 659
 660 static void gas_query_start_cb(struct wpa_radio_work *work, int deinit)
 661 {
 662         struct gas_query_pending *query = work->ctx;
 663         struct gas_query *gas = query->gas;
 664         struct wpa_supplicant *wpa_s = gas->wpa_s;
 665
 666         if (deinit) {
 667                 if (work->started) {
 668                         gas->work = NULL;
 669                         gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
 670                         return;
 671                 }
 672
 673                 gas_query_free(query, 1);
 674                 return;
 675         }
 676
 677         if (wpas_update_random_addr_disassoc(wpa_s) < 0) {
 678                 wpa_msg(wpa_s, MSG_INFO,
 679                         "Failed to assign random MAC address for GAS");
 680                 gas_query_free(query, 1);
 681                 radio_work_done(work);
 682                 return;
 683         }
 684
 685         gas->work = work;
 686         gas_query_tx_initial_req(gas, query);
 687 }
 688
 689
 690 static void gas_query_tx_initial_req(struct gas_query *gas,
 691                                      struct gas_query_pending *query)
 692 {
 693         if (gas_query_tx(gas, query, query->req,
 694                          GAS_QUERY_WAIT_TIME_INITIAL) < 0) {
 695                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 696                            MACSTR, MAC2STR(query->addr));
 697                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 698                 return;
 699         }
 700         gas->current = query;
 701
 702         wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
 703                    query->dialog_token);
 704         eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 705                                gas_query_timeout, gas, query);
 706 }
 707
 708
 709 static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst)
 710 {
 711         static int next_start = 0;
 712         int dialog_token;
 713
 714         for (dialog_token = 0; dialog_token < 256; dialog_token++) {
 715                 if (gas_query_dialog_token_available(
 716                             gas, dst, (next_start + dialog_token) % 256))
 717                         break;
 718         }
 719         if (dialog_token == 256)
 720                 return -1; /* Too many pending queries */
 721         dialog_token = (next_start + dialog_token) % 256;
 722         next_start = (dialog_token + 1) % 256;
 723         return dialog_token;
 724 }
 725
 726
 727 /**
 728  * gas_query_req - Request a GAS query
 729  * @gas: GAS query data from gas_query_init()
 730  * @dst: Destination MAC address for the query
 731  * @freq: Frequency (in MHz) for the channel on which to send the query
 732  * @req: GAS query payload (to be freed by gas_query module in case of success
 733  *      return)
 734  * @cb: Callback function for reporting GAS query result and response
 735  * @ctx: Context pointer to use with the @cb call
 736  * Returns: dialog token (>= 0) on success or -1 on failure
 737  */
 738 int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
 739                   struct wpabuf *req,
 740                   void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
 741                              enum gas_query_result result,
 742                              const struct wpabuf *adv_proto,
 743                              const struct wpabuf *resp, u16 status_code),
 744                   void *ctx)
 745 {
 746         struct gas_query_pending *query;
 747         int dialog_token;
 748
 749         if (wpabuf_len(req) < 3)
 750                 return -1;
 751
 752         dialog_token = gas_query_new_dialog_token(gas, dst);
 753         if (dialog_token < 0)
 754                 return -1;
 755
 756         query = os_zalloc(sizeof(*query));
 757         if (query == NULL)
 758                 return -1;
 759
 760         query->gas = gas;
 761         os_memcpy(query->addr, dst, ETH_ALEN);
 762         query->dialog_token = dialog_token;
 763         query->freq = freq;
 764         query->cb = cb;
 765         query->ctx = ctx;
 766         query->req = req;
 767         dl_list_add(&gas->pending, &query->list);
 768
 769         *(wpabuf_mhead_u8(req) + 2) = dialog_token;
 770
 771         wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
 772                 " dialog_token=%u freq=%d",
 773                 MAC2STR(query->addr), query->dialog_token, query->freq);
 774
 775         if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
 776                            query) < 0) {
 777                 query->req = NULL; /* caller will free this in error case */
 778                 gas_query_free(query, 1);
 779                 return -1;
 780         }
 781
 782         return dialog_token;
 783 }