1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "att_server.c" 39 40 41 // 42 // ATT Server Globals 43 // 44 45 #include <stdint.h> 46 #include <string.h> 47 #include <inttypes.h> 48 49 #include "btstack_config.h" 50 51 #include "att_dispatch.h" 52 #include "ble/att_db.h" 53 #include "ble/att_server.h" 54 #include "ble/core.h" 55 #include "ble/le_device_db.h" 56 #include "ble/sm.h" 57 #include "btstack_debug.h" 58 #include "btstack_event.h" 59 #include "btstack_memory.h" 60 #include "btstack_run_loop.h" 61 #include "gap.h" 62 #include "hci.h" 63 #include "hci_dump.h" 64 #include "l2cap.h" 65 #include "btstack_tlv.h" 66 #ifdef ENABLE_LE_SIGNED_WRITE 67 #include "ble/sm.h" 68 #endif 69 70 #ifndef NVN_NUM_GATT_SERVER_CCC 71 #define NVN_NUM_GATT_SERVER_CCC 20 72 #endif 73 74 static void att_run_for_context(att_server_t * att_server); 75 static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle); 76 static btstack_packet_handler_t att_server_packet_handler_for_handle(uint16_t handle); 77 static void att_server_persistent_ccc_restore(att_server_t * att_server); 78 static void att_server_persistent_ccc_clear(att_server_t * att_server); 79 80 typedef enum { 81 ATT_SERVER_RUN_PHASE_1_REQUESTS, 82 ATT_SERVER_RUN_PHASE_2_INDICATIONS, 83 ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS, 84 } att_server_run_phase_t; 85 86 // 87 typedef struct { 88 uint32_t seq_nr; 89 uint16_t att_handle; 90 uint8_t value; 91 uint8_t device_index; 92 } persistent_ccc_entry_t; 93 94 // global 95 static btstack_packet_callback_registration_t hci_event_callback_registration; 96 static btstack_packet_callback_registration_t sm_event_callback_registration; 97 static btstack_packet_handler_t att_client_packet_handler = NULL; 98 static btstack_linked_list_t service_handlers; 99 static btstack_context_callback_registration_t att_client_waiting_for_can_send_registration; 100 101 static att_read_callback_t att_server_client_read_callback; 102 static att_write_callback_t att_server_client_write_callback; 103 104 // round robin 105 static hci_con_handle_t att_server_last_can_send_now = HCI_CON_HANDLE_INVALID; 106 107 static att_server_t * att_server_for_handle(hci_con_handle_t con_handle){ 108 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 109 if (!hci_connection) return NULL; 110 return &hci_connection->att_server; 111 } 112 113 #ifdef ENABLE_LE_SIGNED_WRITE 114 static att_server_t * att_server_for_state(att_server_state_t state){ 115 btstack_linked_list_iterator_t it; 116 hci_connections_get_iterator(&it); 117 while(btstack_linked_list_iterator_has_next(&it)){ 118 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 119 att_server_t * att_server = &connection->att_server; 120 if (att_server->state == state) return att_server; 121 } 122 return NULL; 123 } 124 #endif 125 126 static void att_handle_value_indication_notify_client(uint8_t status, uint16_t client_handle, uint16_t attribute_handle){ 127 btstack_packet_handler_t packet_handler = att_server_packet_handler_for_handle(attribute_handle); 128 if (!packet_handler) return; 129 130 uint8_t event[7]; 131 int pos = 0; 132 event[pos++] = ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE; 133 event[pos++] = sizeof(event) - 2; 134 event[pos++] = status; 135 little_endian_store_16(event, pos, client_handle); 136 pos += 2; 137 little_endian_store_16(event, pos, attribute_handle); 138 (*packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event)); 139 } 140 141 static void att_emit_event_to_all(const uint8_t * event, uint16_t size){ 142 // dispatch to app level handler 143 if (att_client_packet_handler){ 144 (*att_client_packet_handler)(HCI_EVENT_PACKET, 0, (uint8_t*) event, size); 145 } 146 147 // dispatch to service handlers 148 btstack_linked_list_iterator_t it; 149 btstack_linked_list_iterator_init(&it, &service_handlers); 150 while (btstack_linked_list_iterator_has_next(&it)){ 151 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 152 if (!handler->packet_handler) continue; 153 (*handler->packet_handler)(HCI_EVENT_PACKET, 0, (uint8_t*) event, size); 154 } 155 } 156 157 static void att_emit_mtu_event(hci_con_handle_t con_handle, uint16_t mtu){ 158 uint8_t event[6]; 159 int pos = 0; 160 event[pos++] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 161 event[pos++] = sizeof(event) - 2; 162 little_endian_store_16(event, pos, con_handle); 163 pos += 2; 164 little_endian_store_16(event, pos, mtu); 165 166 // also dispatch to GATT Clients 167 att_dispatch_server_mtu_exchanged(con_handle, mtu); 168 169 // dispatch to app level handler and service handlers 170 att_emit_event_to_all(&event[0], sizeof(event)); 171 } 172 173 static void att_emit_can_send_now_event(void * context){ 174 UNUSED(context); 175 if (!att_client_packet_handler) return; 176 177 uint8_t event[] = { ATT_EVENT_CAN_SEND_NOW, 0}; 178 (*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event)); 179 } 180 181 static void att_handle_value_indication_timeout(btstack_timer_source_t *ts){ 182 void * context = btstack_run_loop_get_timer_context(ts); 183 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) context; 184 att_server_t * att_server = att_server_for_handle(con_handle); 185 if (!att_server) return; 186 // @note: after a transcation timeout, no more requests shall be sent over this ATT Bearer 187 // (that's why we don't reset the value_indication_handle) 188 uint16_t att_handle = att_server->value_indication_handle; 189 att_handle_value_indication_notify_client(ATT_HANDLE_VALUE_INDICATION_TIMEOUT, att_server->connection.con_handle, att_handle); 190 } 191 192 static void att_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 193 194 UNUSED(channel); // ok: there is no channel 195 UNUSED(size); // ok: handling own l2cap events 196 197 att_server_t * att_server; 198 hci_con_handle_t con_handle; 199 200 switch (packet_type) { 201 202 case HCI_EVENT_PACKET: 203 switch (hci_event_packet_get_type(packet)) { 204 205 case HCI_EVENT_LE_META: 206 switch (packet[2]) { 207 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 208 con_handle = little_endian_read_16(packet, 4); 209 att_server = att_server_for_handle(con_handle); 210 if (!att_server) break; 211 // store connection info 212 att_server->peer_addr_type = packet[7]; 213 reverse_bd_addr(&packet[8], att_server->peer_address); 214 att_server->connection.con_handle = con_handle; 215 // reset connection properties 216 att_server->state = ATT_SERVER_IDLE; 217 att_server->connection.mtu = ATT_DEFAULT_MTU; 218 att_server->connection.max_mtu = l2cap_max_le_mtu(); 219 if (att_server->connection.max_mtu > ATT_REQUEST_BUFFER_SIZE){ 220 att_server->connection.max_mtu = ATT_REQUEST_BUFFER_SIZE; 221 } 222 att_server->connection.encryption_key_size = 0; 223 att_server->connection.authenticated = 0; 224 att_server->connection.authorized = 0; 225 // workaround: identity resolving can already be complete, at least store result 226 att_server->ir_le_device_db_index = sm_le_device_index(con_handle); 227 att_server->pairing_active = 0; 228 // notify all 229 att_emit_event_to_all(packet, size); 230 break; 231 232 default: 233 break; 234 } 235 break; 236 237 case HCI_EVENT_ENCRYPTION_CHANGE: 238 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 239 // check handle 240 con_handle = little_endian_read_16(packet, 3); 241 att_server = att_server_for_handle(con_handle); 242 if (!att_server) break; 243 att_server->connection.encryption_key_size = gap_encryption_key_size(con_handle); 244 att_server->connection.authenticated = gap_authenticated(con_handle); 245 att_server->connection.secure_connection = gap_secure_connection(con_handle); 246 log_info("encrypted key size %u, authenticated %u, secure connectipon %u", 247 att_server->connection.encryption_key_size, att_server->connection.authenticated, att_server->connection.secure_connection); 248 if (hci_event_packet_get_type(packet) == HCI_EVENT_ENCRYPTION_CHANGE){ 249 // restore CCC values when encrypted 250 if (hci_event_encryption_change_get_encryption_enabled(packet)){ 251 att_server_persistent_ccc_restore(att_server); 252 } 253 } 254 att_run_for_context(att_server); 255 break; 256 257 case HCI_EVENT_DISCONNECTION_COMPLETE: 258 // check handle 259 con_handle = hci_event_disconnection_complete_get_connection_handle(packet); 260 att_server = att_server_for_handle(con_handle); 261 if (!att_server) break; 262 att_clear_transaction_queue(&att_server->connection); 263 att_server->connection.con_handle = 0; 264 att_server->pairing_active = 0; 265 att_server->state = ATT_SERVER_IDLE; 266 if (att_server->value_indication_handle){ 267 btstack_run_loop_remove_timer(&att_server->value_indication_timer); 268 uint16_t att_handle = att_server->value_indication_handle; 269 att_server->value_indication_handle = 0; // reset error state 270 att_handle_value_indication_notify_client(ATT_HANDLE_VALUE_INDICATION_DISCONNECT, att_server->connection.con_handle, att_handle); 271 } 272 // notify all 273 att_emit_event_to_all(packet, size); 274 break; 275 276 // Identity Resolving 277 case SM_EVENT_IDENTITY_RESOLVING_STARTED: 278 con_handle = sm_event_identity_resolving_started_get_handle(packet); 279 att_server = att_server_for_handle(con_handle); 280 if (!att_server) break; 281 log_info("SM_EVENT_IDENTITY_RESOLVING_STARTED"); 282 att_server->ir_lookup_active = 1; 283 break; 284 case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED: 285 con_handle = sm_event_identity_created_get_handle(packet); 286 att_server = att_server_for_handle(con_handle); 287 if (!att_server) return; 288 att_server->ir_lookup_active = 0; 289 att_server->ir_le_device_db_index = sm_event_identity_resolving_succeeded_get_index(packet); 290 log_info("SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED"); 291 att_run_for_context(att_server); 292 break; 293 case SM_EVENT_IDENTITY_RESOLVING_FAILED: 294 con_handle = sm_event_identity_resolving_failed_get_handle(packet); 295 att_server = att_server_for_handle(con_handle); 296 if (!att_server) break; 297 log_info("SM_EVENT_IDENTITY_RESOLVING_FAILED"); 298 att_server->ir_lookup_active = 0; 299 att_server->ir_le_device_db_index = -1; 300 att_run_for_context(att_server); 301 break; 302 303 // Pairing started - delete stored CCC values 304 // - assumes pairing indicates either new device or re-pairing, in both cases there should be no stored CCC values 305 // - assumes that all events have the con handle as the first field 306 case SM_EVENT_JUST_WORKS_REQUEST: 307 case SM_EVENT_PASSKEY_DISPLAY_NUMBER: 308 case SM_EVENT_PASSKEY_INPUT_NUMBER: 309 case SM_EVENT_NUMERIC_COMPARISON_REQUEST: 310 con_handle = sm_event_just_works_request_get_handle(packet); 311 att_server = att_server_for_handle(con_handle); 312 if (!att_server) break; 313 att_server->pairing_active = 1; 314 log_info("SM Pairing started"); 315 if (att_server->ir_le_device_db_index < 0) break; 316 att_server_persistent_ccc_clear(att_server); 317 // index not valid anymore 318 att_server->ir_le_device_db_index = -1; 319 break; 320 321 // Bonding completed 322 case SM_EVENT_IDENTITY_CREATED: 323 con_handle = sm_event_identity_created_get_handle(packet); 324 att_server = att_server_for_handle(con_handle); 325 if (!att_server) return; 326 att_server->pairing_active = 0; 327 att_server->ir_le_device_db_index = sm_event_identity_created_get_index(packet); 328 att_run_for_context(att_server); 329 break; 330 331 // Pairing complete (with/without bonding=storing of pairing information) 332 case SM_EVENT_PAIRING_COMPLETE: 333 con_handle = sm_event_pairing_complete_get_handle(packet); 334 att_server = att_server_for_handle(con_handle); 335 if (!att_server) return; 336 att_server->pairing_active = 0; 337 att_run_for_context(att_server); 338 break; 339 340 // Authorization 341 case SM_EVENT_AUTHORIZATION_RESULT: { 342 con_handle = sm_event_authorization_result_get_handle(packet); 343 att_server = att_server_for_handle(con_handle); 344 if (!att_server) break; 345 att_server->connection.authorized = sm_event_authorization_result_get_authorization_result(packet); 346 att_dispatch_server_request_can_send_now_event(con_handle); 347 break; 348 } 349 default: 350 break; 351 } 352 break; 353 default: 354 break; 355 } 356 } 357 358 #ifdef ENABLE_LE_SIGNED_WRITE 359 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){ 360 361 att_server_t * att_server = att_server_for_state(ATT_SERVER_W4_SIGNED_WRITE_VALIDATION); 362 if (!att_server) return; 363 364 uint8_t hash_flipped[8]; 365 reverse_64(hash, hash_flipped); 366 if (memcmp(hash_flipped, &att_server->request_buffer[att_server->request_size-8], 8)){ 367 log_info("ATT Signed Write, invalid signature"); 368 att_server->state = ATT_SERVER_IDLE; 369 return; 370 } 371 log_info("ATT Signed Write, valid signature"); 372 373 // update sequence number 374 uint32_t counter_packet = little_endian_read_32(att_server->request_buffer, att_server->request_size-12); 375 le_device_db_remote_counter_set(att_server->ir_le_device_db_index, counter_packet+1); 376 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 377 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 378 } 379 #endif 380 381 // pre: att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED 382 // pre: can send now 383 // returns: 1 if packet was sent 384 static int att_server_process_validated_request(att_server_t * att_server){ 385 386 l2cap_reserve_packet_buffer(); 387 uint8_t * att_response_buffer = l2cap_get_outgoing_buffer(); 388 uint16_t att_response_size = att_handle_request(&att_server->connection, att_server->request_buffer, att_server->request_size, att_response_buffer); 389 390 #ifdef ENABLE_ATT_DELAYED_RESPONSE 391 if (att_response_size == ATT_READ_RESPONSE_PENDING || att_response_size == ATT_INTERNAL_WRITE_RESPONSE_PENDING){ 392 // update state 393 att_server->state = ATT_SERVER_RESPONSE_PENDING; 394 395 // callback with handle ATT_READ_RESPONSE_PENDING for reads 396 if (att_response_size == ATT_READ_RESPONSE_PENDING){ 397 att_server_client_read_callback(att_server->connection.con_handle, ATT_READ_RESPONSE_PENDING, 0, NULL, 0); 398 } 399 400 // free reserved buffer 401 l2cap_release_packet_buffer(); 402 return 0; 403 } 404 #endif 405 406 // intercept "insufficient authorization" for authenticated connections to allow for user authorization 407 if ((att_response_size >= 4) 408 && (att_response_buffer[0] == ATT_ERROR_RESPONSE) 409 && (att_response_buffer[4] == ATT_ERROR_INSUFFICIENT_AUTHORIZATION) 410 && (att_server->connection.authenticated)){ 411 412 switch (gap_authorization_state(att_server->connection.con_handle)){ 413 case AUTHORIZATION_UNKNOWN: 414 l2cap_release_packet_buffer(); 415 sm_request_pairing(att_server->connection.con_handle); 416 return 0; 417 case AUTHORIZATION_PENDING: 418 l2cap_release_packet_buffer(); 419 return 0; 420 default: 421 break; 422 } 423 } 424 425 att_server->state = ATT_SERVER_IDLE; 426 if (att_response_size == 0) { 427 l2cap_release_packet_buffer(); 428 return 0; 429 } 430 431 l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, att_response_size); 432 433 // notify client about MTU exchange result 434 if (att_response_buffer[0] == ATT_EXCHANGE_MTU_RESPONSE){ 435 att_emit_mtu_event(att_server->connection.con_handle, att_server->connection.mtu); 436 } 437 return 1; 438 } 439 440 #ifdef ENABLE_ATT_DELAYED_RESPONSE 441 int att_server_response_ready(hci_con_handle_t con_handle){ 442 att_server_t * att_server = att_server_for_handle(con_handle); 443 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 444 if (att_server->state != ATT_SERVER_RESPONSE_PENDING) return ERROR_CODE_COMMAND_DISALLOWED; 445 446 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 447 att_dispatch_server_request_can_send_now_event(con_handle); 448 return ERROR_CODE_SUCCESS; 449 } 450 #endif 451 452 static void att_run_for_context(att_server_t * att_server){ 453 switch (att_server->state){ 454 case ATT_SERVER_REQUEST_RECEIVED: 455 456 // wait until re-encryption as central is complete 457 if (gap_reconnect_security_setup_active(att_server->connection.con_handle)) break; 458 459 // wait until pairing is complete 460 if (att_server->pairing_active) break; 461 462 #ifdef ENABLE_LE_SIGNED_WRITE 463 if (att_server->request_buffer[0] == ATT_SIGNED_WRITE_COMMAND){ 464 log_info("ATT Signed Write!"); 465 if (!sm_cmac_ready()) { 466 log_info("ATT Signed Write, sm_cmac engine not ready. Abort"); 467 att_server->state = ATT_SERVER_IDLE; 468 return; 469 } 470 if (att_server->request_size < (3 + 12)) { 471 log_info("ATT Signed Write, request to short. Abort."); 472 att_server->state = ATT_SERVER_IDLE; 473 return; 474 } 475 if (att_server->ir_lookup_active){ 476 return; 477 } 478 if (att_server->ir_le_device_db_index < 0){ 479 log_info("ATT Signed Write, CSRK not available"); 480 att_server->state = ATT_SERVER_IDLE; 481 return; 482 } 483 484 // check counter 485 uint32_t counter_packet = little_endian_read_32(att_server->request_buffer, att_server->request_size-12); 486 uint32_t counter_db = le_device_db_remote_counter_get(att_server->ir_le_device_db_index); 487 log_info("ATT Signed Write, DB counter %"PRIu32", packet counter %"PRIu32, counter_db, counter_packet); 488 if (counter_packet < counter_db){ 489 log_info("ATT Signed Write, db reports higher counter, abort"); 490 att_server->state = ATT_SERVER_IDLE; 491 return; 492 } 493 494 // signature is { sequence counter, secure hash } 495 sm_key_t csrk; 496 le_device_db_remote_csrk_get(att_server->ir_le_device_db_index, csrk); 497 att_server->state = ATT_SERVER_W4_SIGNED_WRITE_VALIDATION; 498 log_info("Orig Signature: "); 499 log_info_hexdump( &att_server->request_buffer[att_server->request_size-8], 8); 500 uint16_t attribute_handle = little_endian_read_16(att_server->request_buffer, 1); 501 sm_cmac_signed_write_start(csrk, att_server->request_buffer[0], attribute_handle, att_server->request_size - 15, &att_server->request_buffer[3], counter_packet, att_signed_write_handle_cmac_result); 502 return; 503 } 504 #endif 505 // move on 506 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 507 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 508 break; 509 510 default: 511 break; 512 } 513 } 514 515 static int att_server_data_ready_for_phase(att_server_t * att_server, att_server_run_phase_t phase){ 516 switch (phase){ 517 case ATT_SERVER_RUN_PHASE_1_REQUESTS: 518 return att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 519 case ATT_SERVER_RUN_PHASE_2_INDICATIONS: 520 return (!btstack_linked_list_empty(&att_server->indication_requests) && att_server->value_indication_handle == 0); 521 case ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS: 522 return (!btstack_linked_list_empty(&att_server->notification_requests)); 523 } 524 // avoid warning 525 return 0; 526 } 527 528 static void att_server_trigger_send_for_phase(att_server_t * att_server, att_server_run_phase_t phase){ 529 btstack_context_callback_registration_t * client; 530 switch (phase){ 531 case ATT_SERVER_RUN_PHASE_1_REQUESTS: 532 att_server_process_validated_request(att_server); 533 break; 534 case ATT_SERVER_RUN_PHASE_2_INDICATIONS: 535 client = (btstack_context_callback_registration_t*) att_server->indication_requests; 536 btstack_linked_list_remove(&att_server->indication_requests, (btstack_linked_item_t *) client); 537 client->callback(client->context); 538 break; 539 case ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS: 540 client = (btstack_context_callback_registration_t*) att_server->notification_requests; 541 btstack_linked_list_remove(&att_server->notification_requests, (btstack_linked_item_t *) client); 542 client->callback(client->context); 543 break; 544 } 545 } 546 547 static void att_server_handle_can_send_now(void){ 548 549 hci_con_handle_t request_con_handle = HCI_CON_HANDLE_INVALID; 550 hci_con_handle_t last_send_con_handle = HCI_CON_HANDLE_INVALID; 551 int can_send_now = 1; 552 int phase_index; 553 554 for (phase_index = ATT_SERVER_RUN_PHASE_1_REQUESTS; phase_index <= ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS; phase_index++){ 555 att_server_run_phase_t phase = (att_server_run_phase_t) phase_index; 556 hci_con_handle_t skip_connections_until = att_server_last_can_send_now; 557 while (1){ 558 btstack_linked_list_iterator_t it; 559 hci_connections_get_iterator(&it); 560 while(btstack_linked_list_iterator_has_next(&it)){ 561 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 562 att_server_t * att_server = &connection->att_server; 563 564 int data_ready = att_server_data_ready_for_phase(att_server, phase); 565 566 // log_debug("phase %u, handle 0x%04x, skip until 0x%04x, data ready %u", phase, att_server->connection.con_handle, skip_connections_until, data_ready); 567 568 // skip until last sender found (which is also skipped) 569 if (skip_connections_until != HCI_CON_HANDLE_INVALID){ 570 if (data_ready && request_con_handle == HCI_CON_HANDLE_INVALID){ 571 request_con_handle = att_server->connection.con_handle; 572 } 573 if (skip_connections_until == att_server->connection.con_handle){ 574 skip_connections_until = HCI_CON_HANDLE_INVALID; 575 } 576 continue; 577 }; 578 579 if (data_ready){ 580 if (can_send_now){ 581 att_server_trigger_send_for_phase(att_server, phase); 582 last_send_con_handle = att_server->connection.con_handle; 583 can_send_now = att_dispatch_server_can_send_now(att_server->connection.con_handle); 584 data_ready = att_server_data_ready_for_phase(att_server, phase); 585 if (data_ready && request_con_handle == HCI_CON_HANDLE_INVALID){ 586 request_con_handle = att_server->connection.con_handle; 587 } 588 } else { 589 request_con_handle = att_server->connection.con_handle; 590 break; 591 } 592 } 593 } 594 595 // stop skipping (handles disconnect by last send connection) 596 skip_connections_until = HCI_CON_HANDLE_INVALID; 597 598 // Exit loop, if we cannot send 599 if (!can_send_now) break; 600 601 // Exit loop, if we can send but there are also no further request 602 if (request_con_handle == HCI_CON_HANDLE_INVALID) break; 603 604 // Finally, if we still can send and there are requests, just try again 605 request_con_handle = HCI_CON_HANDLE_INVALID; 606 } 607 // update last send con handle for round robin 608 if (last_send_con_handle != HCI_CON_HANDLE_INVALID){ 609 att_server_last_can_send_now = last_send_con_handle; 610 } 611 } 612 613 if (request_con_handle == HCI_CON_HANDLE_INVALID) return; 614 att_dispatch_server_request_can_send_now_event(request_con_handle); 615 } 616 617 static void att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 618 att_server_t * att_server; 619 620 switch (packet_type){ 621 case HCI_EVENT_PACKET: 622 switch (packet[0]){ 623 case L2CAP_EVENT_CAN_SEND_NOW: 624 att_server_handle_can_send_now(); 625 break; 626 case ATT_EVENT_MTU_EXCHANGE_COMPLETE: 627 // GATT client has negotiated the mtu for this connection 628 att_server = att_server_for_handle(handle); 629 if (!att_server) break; 630 att_server->connection.mtu = little_endian_read_16(packet, 4); 631 break; 632 default: 633 break; 634 } 635 break; 636 637 case ATT_DATA_PACKET: 638 log_debug("ATT Packet, handle 0x%04x", handle); 639 att_server = att_server_for_handle(handle); 640 if (!att_server) break; 641 642 // handle value indication confirms 643 if (packet[0] == ATT_HANDLE_VALUE_CONFIRMATION && att_server->value_indication_handle){ 644 btstack_run_loop_remove_timer(&att_server->value_indication_timer); 645 uint16_t att_handle = att_server->value_indication_handle; 646 att_server->value_indication_handle = 0; 647 att_handle_value_indication_notify_client(0, att_server->connection.con_handle, att_handle); 648 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 649 return; 650 } 651 652 // directly process command 653 // note: signed write cannot be handled directly as authentication needs to be verified 654 if (packet[0] == ATT_WRITE_COMMAND){ 655 att_handle_request(&att_server->connection, packet, size, 0); 656 return; 657 } 658 659 // check size 660 if (size > sizeof(att_server->request_buffer)) { 661 log_info("att_packet_handler: dropping att pdu 0x%02x as size %u > att_server->request_buffer %u", packet[0], size, (int) sizeof(att_server->request_buffer)); 662 return; 663 } 664 665 // last request still in processing? 666 if (att_server->state != ATT_SERVER_IDLE){ 667 log_info("att_packet_handler: skipping att pdu 0x%02x as server not idle (state %u)", packet[0], att_server->state); 668 return; 669 } 670 671 // store request 672 att_server->state = ATT_SERVER_REQUEST_RECEIVED; 673 att_server->request_size = size; 674 memcpy(att_server->request_buffer, packet, size); 675 676 att_run_for_context(att_server); 677 break; 678 } 679 } 680 681 // --------------------- 682 // persistent CCC writes 683 static uint32_t att_server_persistent_ccc_tag_for_index(uint8_t index){ 684 return 'B' << 24 | 'T' << 16 | 'C' << 8 | index; 685 } 686 687 static void att_server_persistent_ccc_write(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t value){ 688 // lookup att_server instance 689 att_server_t * att_server = att_server_for_handle(con_handle); 690 if (!att_server) return; 691 int le_device_index = att_server->ir_le_device_db_index; 692 log_info("Store CCC value 0x%04x for handle 0x%04x of remote %s, le device id %d", value, att_handle, bd_addr_to_str(att_server->peer_address), le_device_index); 693 694 // check if bonded 695 if (le_device_index < 0) return; 696 697 // get btstack_tlv 698 const btstack_tlv_t * tlv_impl = NULL; 699 void * tlv_context; 700 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 701 if (!tlv_impl) return; 702 703 // update ccc tag 704 int index; 705 uint32_t highest_seq_nr = 0; 706 uint32_t lowest_seq_nr = 0; 707 uint32_t tag_for_lowest_seq_nr = 0; 708 uint32_t tag_for_empty = 0; 709 persistent_ccc_entry_t entry; 710 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 711 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 712 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 713 714 // empty/invalid tag 715 if (len != sizeof(persistent_ccc_entry_t)){ 716 tag_for_empty = tag; 717 continue; 718 } 719 // update highest seq nr 720 if (entry.seq_nr > highest_seq_nr){ 721 highest_seq_nr = entry.seq_nr; 722 } 723 // find entry with lowest seq nr 724 if ((tag_for_lowest_seq_nr == 0) || (entry.seq_nr < lowest_seq_nr)){ 725 tag_for_lowest_seq_nr = tag; 726 lowest_seq_nr = entry.seq_nr; 727 } 728 729 if (entry.device_index != le_device_index) continue; 730 if (entry.att_handle != att_handle) continue; 731 732 // found matching entry 733 if (value){ 734 // update 735 if (entry.value == value) { 736 log_info("CCC Index %u: Up-to-date", index); 737 return; 738 } 739 entry.value = value; 740 entry.seq_nr = highest_seq_nr + 1; 741 log_info("CCC Index %u: Store", index); 742 tlv_impl->store_tag(tlv_context, tag, (const uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 743 } else { 744 // delete 745 log_info("CCC Index %u: Delete", index); 746 tlv_impl->delete_tag(tlv_context, tag); 747 } 748 return; 749 } 750 751 log_info("tag_for_empy %"PRIx32", tag_for_lowest_seq_nr %"PRIx32, tag_for_empty, tag_for_lowest_seq_nr); 752 753 if (value == 0){ 754 // done 755 return; 756 } 757 758 uint32_t tag_to_use = 0; 759 if (tag_for_empty){ 760 tag_to_use = tag_for_empty; 761 } else if (tag_for_lowest_seq_nr){ 762 tag_to_use = tag_for_lowest_seq_nr; 763 } else { 764 // should not happen 765 return; 766 } 767 // store ccc tag 768 entry.seq_nr = highest_seq_nr + 1; 769 entry.device_index = le_device_index; 770 entry.att_handle = att_handle; 771 entry.value = value; 772 tlv_impl->store_tag(tlv_context, tag_to_use, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 773 } 774 775 static void att_server_persistent_ccc_clear(att_server_t * att_server){ 776 if (!att_server) return; 777 int le_device_index = att_server->ir_le_device_db_index; 778 log_info("Clear CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index); 779 // check if bonded 780 if (le_device_index < 0) return; 781 // get btstack_tlv 782 const btstack_tlv_t * tlv_impl = NULL; 783 void * tlv_context; 784 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 785 if (!tlv_impl) return; 786 // get all ccc tag 787 int index; 788 persistent_ccc_entry_t entry; 789 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 790 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 791 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 792 if (len != sizeof(persistent_ccc_entry_t)) continue; 793 if (entry.device_index != le_device_index) continue; 794 // delete entry 795 log_info("CCC Index %u: Delete", index); 796 tlv_impl->delete_tag(tlv_context, tag); 797 } 798 } 799 800 static void att_server_persistent_ccc_restore(att_server_t * att_server){ 801 if (!att_server) return; 802 int le_device_index = att_server->ir_le_device_db_index; 803 log_info("Restore CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index); 804 // check if bonded 805 if (le_device_index < 0) return; 806 // get btstack_tlv 807 const btstack_tlv_t * tlv_impl = NULL; 808 void * tlv_context; 809 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 810 if (!tlv_impl) return; 811 // get all ccc tag 812 int index; 813 persistent_ccc_entry_t entry; 814 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 815 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 816 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 817 if (len != sizeof(persistent_ccc_entry_t)) continue; 818 if (entry.device_index != le_device_index) continue; 819 // simulate write callback 820 uint16_t attribute_handle = entry.att_handle; 821 uint8_t value[2]; 822 little_endian_store_16(value, 0, entry.value); 823 att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle); 824 if (!callback) continue; 825 log_info("CCC Index %u: Set Attribute handle 0x%04x to value 0x%04x", index, attribute_handle, entry.value ); 826 (*callback)(att_server->connection.con_handle, attribute_handle, ATT_TRANSACTION_MODE_NONE, 0, value, sizeof(value)); 827 } 828 } 829 830 // persistent CCC writes 831 // --------------------- 832 833 // gatt service management 834 static att_service_handler_t * att_service_handler_for_handle(uint16_t handle){ 835 btstack_linked_list_iterator_t it; 836 btstack_linked_list_iterator_init(&it, &service_handlers); 837 while (btstack_linked_list_iterator_has_next(&it)){ 838 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 839 if (handler->start_handle > handle) continue; 840 if (handler->end_handle < handle) continue; 841 return handler; 842 } 843 return NULL; 844 } 845 static att_read_callback_t att_server_read_callback_for_handle(uint16_t handle){ 846 att_service_handler_t * handler = att_service_handler_for_handle(handle); 847 if (handler) return handler->read_callback; 848 return att_server_client_read_callback; 849 } 850 851 static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle){ 852 att_service_handler_t * handler = att_service_handler_for_handle(handle); 853 if (handler) return handler->write_callback; 854 return att_server_client_write_callback; 855 } 856 857 static btstack_packet_handler_t att_server_packet_handler_for_handle(uint16_t handle){ 858 att_service_handler_t * handler = att_service_handler_for_handle(handle); 859 if (handler) return handler->packet_handler; 860 return att_client_packet_handler; 861 } 862 863 static void att_notify_write_callbacks(hci_con_handle_t con_handle, uint16_t transaction_mode){ 864 // notify all callbacks 865 btstack_linked_list_iterator_t it; 866 btstack_linked_list_iterator_init(&it, &service_handlers); 867 while (btstack_linked_list_iterator_has_next(&it)){ 868 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 869 if (!handler->write_callback) continue; 870 (*handler->write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0); 871 } 872 if (!att_server_client_write_callback) return; 873 (*att_server_client_write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0); 874 } 875 876 // returns first reported error or 0 877 static uint8_t att_validate_prepared_write(hci_con_handle_t con_handle){ 878 btstack_linked_list_iterator_t it; 879 btstack_linked_list_iterator_init(&it, &service_handlers); 880 while (btstack_linked_list_iterator_has_next(&it)){ 881 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 882 if (!handler->write_callback) continue; 883 uint8_t error_code = (*handler->write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0); 884 if (error_code) return error_code; 885 } 886 if (!att_server_client_write_callback) return 0; 887 return (*att_server_client_write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0); 888 } 889 890 static uint16_t att_server_read_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){ 891 att_read_callback_t callback = att_server_read_callback_for_handle(attribute_handle); 892 if (!callback) return 0; 893 return (*callback)(con_handle, attribute_handle, offset, buffer, buffer_size); 894 } 895 896 static int att_server_write_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){ 897 switch (transaction_mode){ 898 case ATT_TRANSACTION_MODE_VALIDATE: 899 return att_validate_prepared_write(con_handle); 900 case ATT_TRANSACTION_MODE_EXECUTE: 901 case ATT_TRANSACTION_MODE_CANCEL: 902 att_notify_write_callbacks(con_handle, transaction_mode); 903 return 0; 904 default: 905 break; 906 } 907 908 // track CCC writes 909 if (att_is_persistent_ccc(attribute_handle) && offset == 0 && buffer_size == 2){ 910 att_server_persistent_ccc_write(con_handle, attribute_handle, little_endian_read_16(buffer, 0)); 911 } 912 913 att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle); 914 if (!callback) return 0; 915 return (*callback)(con_handle, attribute_handle, transaction_mode, offset, buffer, buffer_size); 916 } 917 918 /** 919 * @brief register read/write callbacks for specific handle range 920 * @param att_service_handler_t 921 */ 922 void att_server_register_service_handler(att_service_handler_t * handler){ 923 if (att_service_handler_for_handle(handler->start_handle) || 924 att_service_handler_for_handle(handler->end_handle)){ 925 log_error("handler for range 0x%04x-0x%04x already registered", handler->start_handle, handler->end_handle); 926 return; 927 } 928 btstack_linked_list_add(&service_handlers, (btstack_linked_item_t*) handler); 929 } 930 931 void att_server_init(uint8_t const * db, att_read_callback_t read_callback, att_write_callback_t write_callback){ 932 933 // store callbacks 934 att_server_client_read_callback = read_callback; 935 att_server_client_write_callback = write_callback; 936 937 // register for HCI Events 938 hci_event_callback_registration.callback = &att_event_packet_handler; 939 hci_add_event_handler(&hci_event_callback_registration); 940 941 // register for SM events 942 sm_event_callback_registration.callback = &att_event_packet_handler; 943 sm_add_event_handler(&sm_event_callback_registration); 944 945 // and L2CAP ATT Server PDUs 946 att_dispatch_register_server(att_packet_handler); 947 948 att_set_db(db); 949 att_set_read_callback(att_server_read_callback); 950 att_set_write_callback(att_server_write_callback); 951 952 } 953 954 void att_server_register_packet_handler(btstack_packet_handler_t handler){ 955 att_client_packet_handler = handler; 956 } 957 958 959 // to be deprecated 960 int att_server_can_send_packet_now(hci_con_handle_t con_handle){ 961 return att_dispatch_server_can_send_now(con_handle); 962 } 963 964 int att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){ 965 return att_server_request_to_send_notification(callback_registration, con_handle); 966 } 967 968 void att_server_request_can_send_now_event(hci_con_handle_t con_handle){ 969 att_client_waiting_for_can_send_registration.callback = &att_emit_can_send_now_event; 970 att_server_request_to_send_notification(&att_client_waiting_for_can_send_registration, con_handle); 971 } 972 // end of deprecated 973 974 int att_server_request_to_send_notification(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){ 975 att_server_t * att_server = att_server_for_handle(con_handle); 976 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 977 btstack_linked_list_add_tail(&att_server->notification_requests, (btstack_linked_item_t*) callback_registration); 978 att_dispatch_server_request_can_send_now_event(con_handle); 979 return ERROR_CODE_SUCCESS; 980 } 981 982 int att_server_request_to_send_indication(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){ 983 att_server_t * att_server = att_server_for_handle(con_handle); 984 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 985 btstack_linked_list_add_tail(&att_server->indication_requests, (btstack_linked_item_t*) callback_registration); 986 att_dispatch_server_request_can_send_now_event(con_handle); 987 return ERROR_CODE_SUCCESS; 988 } 989 990 int att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len){ 991 att_server_t * att_server = att_server_for_handle(con_handle); 992 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 993 994 if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL; 995 996 l2cap_reserve_packet_buffer(); 997 uint8_t * packet_buffer = l2cap_get_outgoing_buffer(); 998 uint16_t size = att_prepare_handle_value_notification(&att_server->connection, attribute_handle, value, value_len, packet_buffer); 999 return l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size); 1000 } 1001 1002 int att_server_indicate(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len){ 1003 att_server_t * att_server = att_server_for_handle(con_handle); 1004 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 1005 1006 if (att_server->value_indication_handle) return ATT_HANDLE_VALUE_INDICATION_IN_PROGRESS; 1007 if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL; 1008 1009 // track indication 1010 att_server->value_indication_handle = attribute_handle; 1011 btstack_run_loop_set_timer_handler(&att_server->value_indication_timer, att_handle_value_indication_timeout); 1012 btstack_run_loop_set_timer(&att_server->value_indication_timer, ATT_TRANSACTION_TIMEOUT_MS); 1013 btstack_run_loop_add_timer(&att_server->value_indication_timer); 1014 1015 l2cap_reserve_packet_buffer(); 1016 uint8_t * packet_buffer = l2cap_get_outgoing_buffer(); 1017 uint16_t size = att_prepare_handle_value_indication(&att_server->connection, attribute_handle, value, value_len, packet_buffer); 1018 l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size); 1019 return 0; 1020 } 1021 1022 uint16_t att_server_get_mtu(hci_con_handle_t con_handle){ 1023 att_server_t * att_server = att_server_for_handle(con_handle); 1024 if (!att_server) return 0; 1025 return att_server->connection.mtu; 1026 } 1027