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 *query;
 157         struct gas_query *gas = wpa_s->gas;
 158
 159         if (gas->current == NULL) {
 160                 wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
 161                            MACSTR " result=%d - no query in progress",
 162                            freq, MAC2STR(dst), result);
 163                 return;
 164         }
 165
 166         query = gas->current;
 167
 168         wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
 169                    " result=%d query=%p dialog_token=%u",
 170                    freq, MAC2STR(dst), result, query, query->dialog_token);
 171         if (os_memcmp(dst, query->addr, ETH_ALEN) != 0) {
 172                 wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
 173                 return;
 174         }
 175
 176         if (result == OFFCHANNEL_SEND_ACTION_SUCCESS) {
 177                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 178                 eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 179                                        gas_query_timeout, gas, query);
 180         }
 181         if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
 182                 eloop_cancel_timeout(gas_query_timeout, gas, query);
 183                 eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
 184         }
 185 }
 186
 187
 188 static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
 189                         struct wpabuf *req)
 190 {
 191         int res;
 192         wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
 193                    "freq=%d", MAC2STR(query->addr),
 194                    (unsigned int) wpabuf_len(req), query->freq);
 195         res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
 196                                      gas->wpa_s->own_addr, query->addr,
 197                                      wpabuf_head(req), wpabuf_len(req), 1000,
 198                                      gas_query_tx_status, 0);
 199         if (res == 0)
 200                 query->offchannel_tx_started = 1;
 201         return res;
 202 }
 203
 204
 205 static void gas_query_tx_comeback_req(struct gas_query *gas,
 206                                       struct gas_query_pending *query)
 207 {
 208         struct wpabuf *req;
 209
 210         req = gas_build_comeback_req(query->dialog_token);
 211         if (req == NULL) {
 212                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 213                 return;
 214         }
 215
 216         if (gas_query_tx(gas, query, req) < 0) {
 217                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 218                            MACSTR, MAC2STR(query->addr));
 219                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 220         }
 221
 222         wpabuf_free(req);
 223 }
 224
 225
 226 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
 227 {
 228         struct gas_query *gas = eloop_data;
 229         struct gas_query_pending *query = user_ctx;
 230
 231         wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
 232                    MAC2STR(query->addr));
 233         gas_query_tx_comeback_req(gas, query);
 234 }
 235
 236
 237 static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
 238                                             struct gas_query_pending *query,
 239                                             u16 comeback_delay)
 240 {
 241         unsigned int secs, usecs;
 242
 243         secs = (comeback_delay * 1024) / 1000000;
 244         usecs = comeback_delay * 1024 - secs * 1000000;
 245         wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
 246                    " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
 247         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 248         eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
 249                                gas, query);
 250 }
 251
 252
 253 static void gas_query_rx_initial(struct gas_query *gas,
 254                                  struct gas_query_pending *query,
 255                                  const u8 *adv_proto, const u8 *resp,
 256                                  size_t len, u16 comeback_delay)
 257 {
 258         wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
 259                    MACSTR " (dialog_token=%u comeback_delay=%u)",
 260                    MAC2STR(query->addr), query->dialog_token, comeback_delay);
 261
 262         query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
 263         if (query->adv_proto == NULL) {
 264                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 265                 return;
 266         }
 267
 268         if (comeback_delay) {
 269                 query->wait_comeback = 1;
 270                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 271                 return;
 272         }
 273
 274         /* Query was completed without comeback mechanism */
 275         if (gas_query_append(query, resp, len) < 0) {
 276                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 277                 return;
 278         }
 279
 280         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 281 }
 282
 283
 284 static void gas_query_rx_comeback(struct gas_query *gas,
 285                                   struct gas_query_pending *query,
 286                                   const u8 *adv_proto, const u8 *resp,
 287                                   size_t len, u8 frag_id, u8 more_frags,
 288                                   u16 comeback_delay)
 289 {
 290         wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
 291                    MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
 292                    "comeback_delay=%u)",
 293                    MAC2STR(query->addr), query->dialog_token, frag_id,
 294                    more_frags, comeback_delay);
 295
 296         if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
 297             os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
 298                       wpabuf_len(query->adv_proto)) != 0) {
 299                 wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
 300                            "between initial and comeback response from "
 301                            MACSTR, MAC2STR(query->addr));
 302                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 303                 return;
 304         }
 305
 306         if (comeback_delay) {
 307                 if (frag_id) {
 308                         wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
 309                                    "with non-zero frag_id and comeback_delay "
 310                                    "from " MACSTR, MAC2STR(query->addr));
 311                         gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 312                         return;
 313                 }
 314                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 315                 return;
 316         }
 317
 318         if (frag_id != query->next_frag_id) {
 319                 wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
 320                            "from " MACSTR, MAC2STR(query->addr));
 321                 if (frag_id + 1 == query->next_frag_id) {
 322                         wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
 323                                    "retry of previous fragment");
 324                         return;
 325                 }
 326                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 327                 return;
 328         }
 329         query->next_frag_id++;
 330
 331         if (gas_query_append(query, resp, len) < 0) {
 332                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 333                 return;
 334         }
 335
 336         if (more_frags) {
 337                 gas_query_tx_comeback_req(gas, query);
 338                 return;
 339         }
 340
 341         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 342 }
 343
 344
 345 /**
 346  * gas_query_rx - Indicate reception of a Public Action frame
 347  * @gas: GAS query data from gas_query_init()
 348  * @da: Destination MAC address of the Action frame
 349  * @sa: Source MAC address of the Action frame
 350  * @bssid: BSSID of the Action frame
 351  * @data: Payload of the Action frame
 352  * @len: Length of @data
 353  * @freq: Frequency (in MHz) on which the frame was received
 354  * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
 355  */
 356 int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
 357                  const u8 *bssid, const u8 *data, size_t len, int freq)
 358 {
 359         struct gas_query_pending *query;
 360         u8 action, dialog_token, frag_id = 0, more_frags = 0;
 361         u16 comeback_delay, resp_len;
 362         const u8 *pos, *adv_proto;
 363
 364         if (gas == NULL || len < 4)
 365                 return -1;
 366
 367         pos = data;
 368         action = *pos++;
 369         dialog_token = *pos++;
 370
 371         if (action != WLAN_PA_GAS_INITIAL_RESP &&
 372             action != WLAN_PA_GAS_COMEBACK_RESP)
 373                 return -1; /* Not a GAS response */
 374
 375         query = gas_query_get_pending(gas, sa, dialog_token);
 376         if (query == NULL) {
 377                 wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
 378                            " dialog token %u", MAC2STR(sa), dialog_token);
 379                 return -1;
 380         }
 381
 382         if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
 383                 wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
 384                            MACSTR " dialog token %u when waiting for comeback "
 385                            "response", MAC2STR(sa), dialog_token);
 386                 return 0;
 387         }
 388
 389         if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
 390                 wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
 391                            MACSTR " dialog token %u when waiting for initial "
 392                            "response", MAC2STR(sa), dialog_token);
 393                 return 0;
 394         }
 395
 396         query->status_code = WPA_GET_LE16(pos);
 397         pos += 2;
 398
 399         if (query->status_code != WLAN_STATUS_SUCCESS) {
 400                 wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
 401                            "%u failed - status code %u",
 402                            MAC2STR(sa), dialog_token, query->status_code);
 403                 gas_query_done(gas, query, GAS_QUERY_FAILURE);
 404                 return 0;
 405         }
 406
 407         if (action == WLAN_PA_GAS_COMEBACK_RESP) {
 408                 if (pos + 1 > data + len)
 409                         return 0;
 410                 frag_id = *pos & 0x7f;
 411                 more_frags = (*pos & 0x80) >> 7;
 412                 pos++;
 413         }
 414
 415         /* Comeback Delay */
 416         if (pos + 2 > data + len)
 417                 return 0;
 418         comeback_delay = WPA_GET_LE16(pos);
 419         pos += 2;
 420
 421         /* Advertisement Protocol element */
 422         if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
 423                 wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
 424                            "Protocol element in the response from " MACSTR,
 425                            MAC2STR(sa));
 426                 return 0;
 427         }
 428
 429         if (*pos != WLAN_EID_ADV_PROTO) {
 430                 wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
 431                            "Protocol element ID %u in response from " MACSTR,
 432                            *pos, MAC2STR(sa));
 433                 return 0;
 434         }
 435
 436         adv_proto = pos;
 437         pos += 2 + pos[1];
 438
 439         /* Query Response Length */
 440         if (pos + 2 > data + len) {
 441                 wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
 442                 return 0;
 443         }
 444         resp_len = WPA_GET_LE16(pos);
 445         pos += 2;
 446
 447         if (pos + resp_len > data + len) {
 448                 wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
 449                            "response from " MACSTR, MAC2STR(sa));
 450                 return 0;
 451         }
 452
 453         if (pos + resp_len < data + len) {
 454                 wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
 455                            "after Query Response from " MACSTR,
 456                            (unsigned int) (data + len - pos - resp_len),
 457                            MAC2STR(sa));
 458         }
 459
 460         if (action == WLAN_PA_GAS_COMEBACK_RESP)
 461                 gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
 462                                       frag_id, more_frags, comeback_delay);
 463         else
 464                 gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
 465                                      comeback_delay);
 466
 467         return 0;
 468 }
 469
 470
 471 static void gas_query_timeout(void *eloop_data, void *user_ctx)
 472 {
 473         struct gas_query *gas = eloop_data;
 474         struct gas_query_pending *query = user_ctx;
 475
 476         wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
 477                    " dialog token %u",
 478                    MAC2STR(query->addr), query->dialog_token);
 479         gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
 480 }
 481
 482
 483 static void gas_service_timeout(void *eloop_data, void *user_ctx)
 484 {
 485         struct gas_query *gas = eloop_data;
 486         struct wpa_supplicant *wpa_s = gas->wpa_s;
 487         struct gas_query_pending *query = user_ctx;
 488         int conn;
 489
 490         conn = wpas_wpa_is_in_progress(wpa_s, 1);
 491         if (conn || wpa_s->scanning || gas->current) {
 492                 wpa_printf(MSG_DEBUG, "GAS: Delaying GAS query Tx while another operation is in progress:%s%s%s",
 493                            conn ? " connection" : "",
 494                            wpa_s->scanning ? " scanning" : "",
 495                            gas->current ? " gas_query" : "");
 496                 eloop_register_timeout(
 497                         GAS_SERVICE_RETRY_PERIOD_MS / 1000,
 498                         (GAS_SERVICE_RETRY_PERIOD_MS % 1000) * 1000,
 499                         gas_service_timeout, gas, query);
 500                 return;
 501         }
 502
 503         if (gas_query_tx(gas, query, query->req) < 0) {
 504                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 505                            MACSTR, MAC2STR(query->addr));
 506                 dl_list_del(&query->list);
 507                 wpabuf_free(query->req);
 508                 os_free(query);
 509                 return;
 510         }
 511         gas->current = query;
 512
 513         wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
 514                    query->dialog_token);
 515         eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
 516                                gas_query_timeout, gas, query);
 517 }
 518
 519
 520 static int gas_query_dialog_token_available(struct gas_query *gas,
 521                                             const u8 *dst, u8 dialog_token)
 522 {
 523         struct gas_query_pending *q;
 524         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 525                 if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
 526                     dialog_token == q->dialog_token)
 527                         return 0;
 528         }
 529
 530         return 1;
 531 }
 532
 533
 534 /**
 535  * gas_query_req - Request a GAS query
 536  * @gas: GAS query data from gas_query_init()
 537  * @dst: Destination MAC address for the query
 538  * @freq: Frequency (in MHz) for the channel on which to send the query
 539  * @req: GAS query payload (to be freed by gas_query module in case of success
 540  *      return)
 541  * @cb: Callback function for reporting GAS query result and response
 542  * @ctx: Context pointer to use with the @cb call
 543  * Returns: dialog token (>= 0) on success or -1 on failure
 544  */
 545 int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
 546                   struct wpabuf *req,
 547                   void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
 548                              enum gas_query_result result,
 549                              const struct wpabuf *adv_proto,
 550                              const struct wpabuf *resp, u16 status_code),
 551                   void *ctx)
 552 {
 553         struct gas_query_pending *query;
 554         int dialog_token;
 555         static int next_start = 0;
 556
 557         if (wpabuf_len(req) < 3)
 558                 return -1;
 559
 560         for (dialog_token = 0; dialog_token < 256; dialog_token++) {
 561                 if (gas_query_dialog_token_available(
 562                             gas, dst, (next_start + dialog_token) % 256))
 563                         break;
 564         }
 565         if (dialog_token == 256)
 566                 return -1; /* Too many pending queries */
 567         dialog_token = (next_start + dialog_token) % 256;
 568         next_start = (dialog_token + 1) % 256;
 569
 570         query = os_zalloc(sizeof(*query));
 571         if (query == NULL)
 572                 return -1;
 573
 574         os_memcpy(query->addr, dst, ETH_ALEN);
 575         query->dialog_token = dialog_token;
 576         query->freq = freq;
 577         query->cb = cb;
 578         query->ctx = ctx;
 579         query->req = req;
 580         dl_list_add(&gas->pending, &query->list);
 581
 582         *(wpabuf_mhead_u8(req) + 2) = dialog_token;
 583
 584         wpa_printf(MSG_DEBUG, "GAS: Starting request for " MACSTR
 585                    " dialog_token %u", MAC2STR(dst), dialog_token);
 586
 587         eloop_register_timeout(0, 0, gas_service_timeout, gas, query);
 588
 589         return dialog_token;
 590 }
 591
 592
 593 /**
 594  * gas_query_cancel - Cancel a pending GAS query
 595  * @gas: GAS query data from gas_query_init()
 596  * @dst: Destination MAC address for the query
 597  * @dialog_token: Dialog token from gas_query_req()
 598  */
 599 void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
 600 {
 601         struct gas_query_pending *query;
 602
 603         query = gas_query_get_pending(gas, dst, dialog_token);
 604         if (query)
 605                 gas_query_done(gas, query, GAS_QUERY_CANCELLED);
 606
 607 }
 608
 609
 610 int gas_query_in_progress(struct gas_query *gas)
 611 {
 612         return gas->current != NULL;
 613 }