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