wpa_supplicant/gas_query.c

   1 /*
   2  * Generic advertisement service (GAS) query
   3  * Copyright (c) 2009, Atheros Communications
   4  * Copyright (c) 2011, Qualcomm Atheros
   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
  25
  26 /**
  27  * struct gas_query_pending - Pending GAS query
  28  */
  29 struct gas_query_pending {
  30         struct dl_list list;
  31         u8 addr[ETH_ALEN];
  32         u8 dialog_token;
  33         u8 next_frag_id;
  34         unsigned int wait_comeback:1;
  35         unsigned int offchannel_tx_started:1;
  36         int freq;
  37         u16 status_code;
  38         struct wpabuf *adv_proto;
  39         struct wpabuf *resp;
  40         void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
  41                    enum gas_query_result result,
  42                    const struct wpabuf *adv_proto,
  43                    const struct wpabuf *resp, u16 status_code);
  44         void *ctx;
  45 };
  46
  47 /**
  48  * struct gas_query - Internal GAS query data
  49  */
  50 struct gas_query {
  51         struct wpa_supplicant *wpa_s;
  52         struct dl_list pending; /* struct gas_query_pending */
  53 };
  54
  55
  56 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
  57 static void gas_query_timeout(void *eloop_data, void *user_ctx);
  58
  59
  60 /**
  61  * gas_query_init - Initialize GAS query component
  62  * @wpa_s: Pointer to wpa_supplicant data
  63  * Returns: Pointer to GAS query data or %NULL on failure
  64  */
  65 struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
  66 {
  67         struct gas_query *gas;
  68
  69         gas = os_zalloc(sizeof(*gas));
  70         if (gas == NULL)
  71                 return NULL;
  72
  73         gas->wpa_s = wpa_s;
  74         dl_list_init(&gas->pending);
  75
  76         return gas;
  77 }
  78
  79
  80 static void gas_query_done(struct gas_query *gas,
  81                            struct gas_query_pending *query,
  82                            enum gas_query_result result)
  83 {
  84         if (query->offchannel_tx_started)
  85                 offchannel_send_action_done(gas->wpa_s);
  86         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  87         eloop_cancel_timeout(gas_query_timeout, gas, query);
  88         dl_list_del(&query->list);
  89         query->cb(query->ctx, query->addr, query->dialog_token, result,
  90                   query->adv_proto, query->resp, query->status_code);
  91         wpabuf_free(query->adv_proto);
  92         wpabuf_free(query->resp);
  93         os_free(query);
  94 }
  95
  96
  97 /**
  98  * gas_query_deinit - Deinitialize GAS query component
  99  * @gas: GAS query data from gas_query_init()
 100  */
 101 void gas_query_deinit(struct gas_query *gas)
 102 {
 103         struct gas_query_pending *query, *next;
 104
 105         if (gas == NULL)
 106                 return;
 107
 108         dl_list_for_each_safe(query, next, &gas->pending,
 109                               struct gas_query_pending, list)
 110                 gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
 111
 112         os_free(gas);
 113 }
 114
 115
 116 static struct gas_query_pending *
 117 gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
 118 {
 119         struct gas_query_pending *q;
 120         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 121                 if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
 122                     q->dialog_token == dialog_token)
 123                         return q;
 124         }
 125         return NULL;
 126 }
 127
 128
 129 static int gas_query_append(struct gas_query_pending *query, const u8 *data,
 130                             size_t len)
 131 {
 132         if (wpabuf_resize(&query->resp, len) < 0) {
 133                 wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
 134                 return -1;
 135         }
 136         wpabuf_put_data(query->resp, data, len);
 137         return 0;
 138 }
 139
 140
 141 static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
 142                         struct wpabuf *req)
 143 {
 144         int res;
 145         wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
 146                    "freq=%d", MAC2STR(query->addr),
 147                    (unsigned int) wpabuf_len(req), query->freq);
 148         res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
 149                                      gas->wpa_s->own_addr, query->addr,
 150                                      wpabuf_head(req), wpabuf_len(req), 1000,
 151                                      NULL, 0);
 152         if (res == 0)
 153                 query->offchannel_tx_started = 1;
 154         return res;
 155 }
 156
 157
 158 static void gas_query_tx_comeback_req(struct gas_query *gas,
 159                                       struct gas_query_pending *query)
 160 {
 161         struct wpabuf *req;
 162
 163         req = gas_build_comeback_req(query->dialog_token);
 164         if (req == NULL) {
 165                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 166                 return;
 167         }
 168
 169         if (gas_query_tx(gas, query, req) < 0) {
 170                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 171                            MACSTR, MAC2STR(query->addr));
 172                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 173         }
 174
 175         wpabuf_free(req);
 176 }
 177
 178
 179 static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
 180 {
 181         struct gas_query *gas = eloop_data;
 182         struct gas_query_pending *query = user_ctx;
 183
 184         wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
 185                    MAC2STR(query->addr));
 186         gas_query_tx_comeback_req(gas, query);
 187 }
 188
 189
 190 static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
 191                                             struct gas_query_pending *query,
 192                                             u16 comeback_delay)
 193 {
 194         unsigned int secs, usecs;
 195
 196         secs = (comeback_delay * 1024) / 1000000;
 197         usecs = comeback_delay * 1024 - secs * 1000000;
 198         wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
 199                    " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
 200         eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
 201         eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
 202                                gas, query);
 203 }
 204
 205
 206 static void gas_query_rx_initial(struct gas_query *gas,
 207                                  struct gas_query_pending *query,
 208                                  const u8 *adv_proto, const u8 *resp,
 209                                  size_t len, u16 comeback_delay)
 210 {
 211         wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
 212                    MACSTR " (dialog_token=%u comeback_delay=%u)",
 213                    MAC2STR(query->addr), query->dialog_token, comeback_delay);
 214
 215         query->adv_proto = wpabuf_alloc_copy(adv_proto, 2 + adv_proto[1]);
 216         if (query->adv_proto == NULL) {
 217                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 218                 return;
 219         }
 220
 221         if (comeback_delay) {
 222                 query->wait_comeback = 1;
 223                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 224                 return;
 225         }
 226
 227         /* Query was completed without comeback mechanism */
 228         if (gas_query_append(query, resp, len) < 0) {
 229                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 230                 return;
 231         }
 232
 233         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 234 }
 235
 236
 237 static void gas_query_rx_comeback(struct gas_query *gas,
 238                                   struct gas_query_pending *query,
 239                                   const u8 *adv_proto, const u8 *resp,
 240                                   size_t len, u8 frag_id, u8 more_frags,
 241                                   u16 comeback_delay)
 242 {
 243         wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
 244                    MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
 245                    "comeback_delay=%u)",
 246                    MAC2STR(query->addr), query->dialog_token, frag_id,
 247                    more_frags, comeback_delay);
 248
 249         if ((size_t) 2 + adv_proto[1] != wpabuf_len(query->adv_proto) ||
 250             os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
 251                       wpabuf_len(query->adv_proto)) != 0) {
 252                 wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
 253                            "between initial and comeback response from "
 254                            MACSTR, MAC2STR(query->addr));
 255                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 256                 return;
 257         }
 258
 259         if (comeback_delay) {
 260                 if (frag_id) {
 261                         wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
 262                                    "with non-zero frag_id and comeback_delay "
 263                                    "from " MACSTR, MAC2STR(query->addr));
 264                         gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 265                         return;
 266                 }
 267                 gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
 268                 return;
 269         }
 270
 271         if (frag_id != query->next_frag_id) {
 272                 wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
 273                            "from " MACSTR, MAC2STR(query->addr));
 274                 if (frag_id + 1 == query->next_frag_id) {
 275                         wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
 276                                    "retry of previous fragment");
 277                         return;
 278                 }
 279                 gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
 280                 return;
 281         }
 282         query->next_frag_id++;
 283
 284         if (gas_query_append(query, resp, len) < 0) {
 285                 gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
 286                 return;
 287         }
 288
 289         if (more_frags) {
 290                 gas_query_tx_comeback_req(gas, query);
 291                 return;
 292         }
 293
 294         gas_query_done(gas, query, GAS_QUERY_SUCCESS);
 295 }
 296
 297
 298 /**
 299  * gas_query_rx - Indicate reception of a Public Action frame
 300  * @gas: GAS query data from gas_query_init()
 301  * @da: Destination MAC address of the Action frame
 302  * @sa: Source MAC address of the Action frame
 303  * @bssid: BSSID of the Action frame
 304  * @data: Payload of the Action frame
 305  * @len: Length of @data
 306  * @freq: Frequency (in MHz) on which the frame was received
 307  * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
 308  */
 309 int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
 310                  const u8 *bssid, const u8 *data, size_t len, int freq)
 311 {
 312         struct gas_query_pending *query;
 313         u8 action, dialog_token, frag_id = 0, more_frags = 0;
 314         u16 comeback_delay, resp_len;
 315         const u8 *pos, *adv_proto;
 316
 317         if (gas == NULL || len < 4)
 318                 return -1;
 319
 320         pos = data;
 321         action = *pos++;
 322         dialog_token = *pos++;
 323
 324         if (action != WLAN_PA_GAS_INITIAL_RESP &&
 325             action != WLAN_PA_GAS_COMEBACK_RESP)
 326                 return -1; /* Not a GAS response */
 327
 328         query = gas_query_get_pending(gas, sa, dialog_token);
 329         if (query == NULL) {
 330                 wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
 331                            " dialog token %u", MAC2STR(sa), dialog_token);
 332                 return -1;
 333         }
 334
 335         if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
 336                 wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
 337                            MACSTR " dialog token %u when waiting for comeback "
 338                            "response", MAC2STR(sa), dialog_token);
 339                 return 0;
 340         }
 341
 342         if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
 343                 wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
 344                            MACSTR " dialog token %u when waiting for initial "
 345                            "response", MAC2STR(sa), dialog_token);
 346                 return 0;
 347         }
 348
 349         query->status_code = WPA_GET_LE16(pos);
 350         pos += 2;
 351
 352         if (query->status_code != WLAN_STATUS_SUCCESS) {
 353                 wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
 354                            "%u failed - status code %u",
 355                            MAC2STR(sa), dialog_token, query->status_code);
 356                 gas_query_done(gas, query, GAS_QUERY_FAILURE);
 357                 return 0;
 358         }
 359
 360         if (action == WLAN_PA_GAS_COMEBACK_RESP) {
 361                 if (pos + 1 > data + len)
 362                         return 0;
 363                 frag_id = *pos & 0x7f;
 364                 more_frags = (*pos & 0x80) >> 7;
 365                 pos++;
 366         }
 367
 368         /* Comeback Delay */
 369         if (pos + 2 > data + len)
 370                 return 0;
 371         comeback_delay = WPA_GET_LE16(pos);
 372         pos += 2;
 373
 374         /* Advertisement Protocol element */
 375         if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
 376                 wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
 377                            "Protocol element in the response from " MACSTR,
 378                            MAC2STR(sa));
 379                 return 0;
 380         }
 381
 382         if (*pos != WLAN_EID_ADV_PROTO) {
 383                 wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
 384                            "Protocol element ID %u in response from " MACSTR,
 385                            *pos, MAC2STR(sa));
 386                 return 0;
 387         }
 388
 389         adv_proto = pos;
 390         pos += 2 + pos[1];
 391
 392         /* Query Response Length */
 393         if (pos + 2 > data + len) {
 394                 wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
 395                 return 0;
 396         }
 397         resp_len = WPA_GET_LE16(pos);
 398         pos += 2;
 399
 400         if (pos + resp_len > data + len) {
 401                 wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
 402                            "response from " MACSTR, MAC2STR(sa));
 403                 return 0;
 404         }
 405
 406         if (pos + resp_len < data + len) {
 407                 wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
 408                            "after Query Response from " MACSTR,
 409                            (unsigned int) (data + len - pos - resp_len),
 410                            MAC2STR(sa));
 411         }
 412
 413         if (action == WLAN_PA_GAS_COMEBACK_RESP)
 414                 gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
 415                                       frag_id, more_frags, comeback_delay);
 416         else
 417                 gas_query_rx_initial(gas, query, adv_proto, pos, resp_len,
 418                                      comeback_delay);
 419
 420         return 0;
 421 }
 422
 423
 424 static void gas_query_timeout(void *eloop_data, void *user_ctx)
 425 {
 426         struct gas_query *gas = eloop_data;
 427         struct gas_query_pending *query = user_ctx;
 428
 429         wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR,
 430                    MAC2STR(query->addr));
 431         gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
 432 }
 433
 434
 435 static int gas_query_dialog_token_available(struct gas_query *gas,
 436                                             const u8 *dst, u8 dialog_token)
 437 {
 438         struct gas_query_pending *q;
 439         dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
 440                 if (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
 441                     dialog_token == q->dialog_token)
 442                         return 0;
 443         }
 444
 445         return 1;
 446 }
 447
 448
 449 /**
 450  * gas_query_req - Request a GAS query
 451  * @gas: GAS query data from gas_query_init()
 452  * @dst: Destination MAC address for the query
 453  * @freq: Frequency (in MHz) for the channel on which to send the query
 454  * @req: GAS query payload
 455  * @cb: Callback function for reporting GAS query result and response
 456  * @ctx: Context pointer to use with the @cb call
 457  * Returns: dialog token (>= 0) on success or -1 on failure
 458  */
 459 int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
 460                   struct wpabuf *req,
 461                   void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
 462                              enum gas_query_result result,
 463                              const struct wpabuf *adv_proto,
 464                              const struct wpabuf *resp, u16 status_code),
 465                   void *ctx)
 466 {
 467         struct gas_query_pending *query;
 468         int dialog_token;
 469         static int next_start = 0;
 470
 471         if (wpabuf_len(req) < 3)
 472                 return -1;
 473
 474         for (dialog_token = 0; dialog_token < 256; dialog_token++) {
 475                 if (gas_query_dialog_token_available(
 476                             gas, dst, (next_start + dialog_token) % 256))
 477                         break;
 478         }
 479         if (dialog_token == 256)
 480                 return -1; /* Too many pending queries */
 481         dialog_token = (next_start + dialog_token) % 256;
 482         next_start = (dialog_token + 1) % 256;
 483
 484         query = os_zalloc(sizeof(*query));
 485         if (query == NULL)
 486                 return -1;
 487
 488         os_memcpy(query->addr, dst, ETH_ALEN);
 489         query->dialog_token = dialog_token;
 490         query->freq = freq;
 491         query->cb = cb;
 492         query->ctx = ctx;
 493         dl_list_add(&gas->pending, &query->list);
 494
 495         *(wpabuf_mhead_u8(req) + 2) = dialog_token;
 496
 497         wpa_printf(MSG_DEBUG, "GAS: Starting request for " MACSTR
 498                    " dialog_token %u", MAC2STR(dst), dialog_token);
 499         if (gas_query_tx(gas, query, req) < 0) {
 500                 wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
 501                            MACSTR, MAC2STR(query->addr));
 502                 dl_list_del(&query->list);
 503                 os_free(query);
 504                 return -1;
 505         }
 506
 507         eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0, gas_query_timeout,
 508                                gas, query);
 509
 510         return dialog_token;
 511 }
 512
 513
 514 /**
 515  * gas_query_cancel - Cancel a pending GAS query
 516  * @gas: GAS query data from gas_query_init()
 517  * @dst: Destination MAC address for the query
 518  * @dialog_token: Dialog token from gas_query_req()
 519  */
 520 void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
 521 {
 522         struct gas_query_pending *query;
 523
 524         query = gas_query_get_pending(gas, dst, dialog_token);
 525         if (query)
 526                 gas_query_done(gas, query, GAS_QUERY_CANCELLED);
 527
 528 }