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 } 529
