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 <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <inttypes.h> 50 51 #include "btstack_config.h" 52 53 #include "att_dispatch.h" 54 #include "ble/att_db.h" 55 #include "ble/att_server.h" 56 #include "ble/core.h" 57 #include "ble/le_device_db.h" 58 #include "ble/sm.h" 59 #include "btstack_debug.h" 60 #include "btstack_event.h" 61 #include "btstack_memory.h" 62 #include "btstack_run_loop.h" 63 #include "gap.h" 64 #include "hci.h" 65 #include "hci_dump.h" 66 #include "l2cap.h" 67 #include "btstack_tlv.h" 68 69 #ifndef NVN_NUM_GATT_SERVER_CCC 70 #define NVN_NUM_GATT_SERVER_CCC 20 71 #endif 72 73 static void att_run_for_context(att_server_t * att_server); 74 static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle); 75 static void att_server_persistent_ccc_restore(att_server_t * att_server); 76 static void att_server_persistent_ccc_clear(att_server_t * att_server); 77 78 // 79 typedef struct { 80 uint32_t seq_nr; 81 uint16_t att_handle; 82 uint8_t value; 83 uint8_t device_index; 84 } persistent_ccc_entry_t; 85 86 // global 87 static btstack_packet_callback_registration_t hci_event_callback_registration; 88 static btstack_packet_callback_registration_t sm_event_callback_registration; 89 static btstack_packet_handler_t att_client_packet_handler = NULL; 90 static btstack_linked_list_t can_send_now_clients; 91 static btstack_linked_list_t service_handlers; 92 static uint8_t att_client_waiting_for_can_send; 93 94 static att_read_callback_t att_server_client_read_callback; 95 static att_write_callback_t att_server_client_write_callback; 96 97 // track CCC 1-entry cache 98 // static att_server_t * att_persistent_ccc_server; 99 // static hci_con_handle_t att_persistent_ccc_con_handle; 100 101 static att_server_t * att_server_for_handle(hci_con_handle_t con_handle){ 102 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 103 if (!hci_connection) return NULL; 104 return &hci_connection->att_server; 105 } 106 107 #ifdef ENABLE_LE_SIGNED_WRITE 108 static att_server_t * att_server_for_state(att_server_state_t state){ 109 btstack_linked_list_iterator_t it; 110 hci_connections_get_iterator(&it); 111 while(btstack_linked_list_iterator_has_next(&it)){ 112 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 113 att_server_t * att_server = &connection->att_server; 114 if (att_server->state == state) return att_server; 115 } 116 return NULL; 117 } 118 #endif 119 120 static void att_handle_value_indication_notify_client(uint8_t status, uint16_t client_handle, uint16_t attribute_handle){ 121 if (!att_client_packet_handler) return; 122 123 uint8_t event[7]; 124 int pos = 0; 125 event[pos++] = ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE; 126 event[pos++] = sizeof(event) - 2; 127 event[pos++] = status; 128 little_endian_store_16(event, pos, client_handle); 129 pos += 2; 130 little_endian_store_16(event, pos, attribute_handle); 131 (*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event)); 132 } 133 134 static void att_emit_mtu_event(hci_con_handle_t con_handle, uint16_t mtu){ 135 if (!att_client_packet_handler) return; 136 137 uint8_t event[6]; 138 int pos = 0; 139 event[pos++] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 140 event[pos++] = sizeof(event) - 2; 141 little_endian_store_16(event, pos, con_handle); 142 pos += 2; 143 little_endian_store_16(event, pos, mtu); 144 att_dispatch_server_mtu_exchanged(con_handle, mtu); 145 (*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event)); 146 } 147 148 static void att_emit_can_send_now_event(void){ 149 if (!att_client_packet_handler) return; 150 151 uint8_t event[] = { ATT_EVENT_CAN_SEND_NOW, 0}; 152 (*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event)); 153 } 154 155 static void att_handle_value_indication_timeout(btstack_timer_source_t *ts){ 156 void * context = btstack_run_loop_get_timer_context(ts); 157 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) context; 158 att_server_t * att_server = att_server_for_handle(con_handle); 159 if (!att_server) return; 160 uint16_t att_handle = att_server->value_indication_handle; 161 att_handle_value_indication_notify_client(ATT_HANDLE_VALUE_INDICATION_TIMEOUT, att_server->connection.con_handle, att_handle); 162 } 163 164 static void att_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 165 166 UNUSED(channel); // ok: there is no channel 167 UNUSED(size); // ok: handling own l2cap events 168 169 att_server_t * att_server; 170 hci_con_handle_t con_handle; 171 172 switch (packet_type) { 173 174 case HCI_EVENT_PACKET: 175 switch (hci_event_packet_get_type(packet)) { 176 177 case HCI_EVENT_LE_META: 178 switch (packet[2]) { 179 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 180 con_handle = little_endian_read_16(packet, 4); 181 att_server = att_server_for_handle(con_handle); 182 if (!att_server) break; 183 // store connection info 184 att_server->peer_addr_type = packet[7]; 185 reverse_bd_addr(&packet[8], att_server->peer_address); 186 att_server->connection.con_handle = con_handle; 187 // reset connection properties 188 att_server->state = ATT_SERVER_IDLE; 189 att_server->connection.mtu = ATT_DEFAULT_MTU; 190 att_server->connection.max_mtu = l2cap_max_le_mtu(); 191 if (att_server->connection.max_mtu > ATT_REQUEST_BUFFER_SIZE){ 192 att_server->connection.max_mtu = ATT_REQUEST_BUFFER_SIZE; 193 } 194 att_server->connection.encryption_key_size = 0; 195 att_server->connection.authenticated = 0; 196 att_server->connection.authorized = 0; 197 // workaround: identity resolving can already be complete, at least store result 198 att_server->ir_le_device_db_index = sm_le_device_index(con_handle); 199 att_server->pairing_active = 0; 200 break; 201 202 default: 203 break; 204 } 205 break; 206 207 case HCI_EVENT_ENCRYPTION_CHANGE: 208 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 209 // check handle 210 con_handle = little_endian_read_16(packet, 3); 211 att_server = att_server_for_handle(con_handle); 212 if (!att_server) break; 213 att_server->connection.encryption_key_size = gap_encryption_key_size(con_handle); 214 att_server->connection.authenticated = gap_authenticated(con_handle); 215 if (hci_event_packet_get_type(packet) == HCI_EVENT_ENCRYPTION_CHANGE){ 216 // restore CCC values when encrypted 217 if (hci_event_encryption_change_get_encryption_enabled(packet)){ 218 att_server_persistent_ccc_restore(att_server); 219 } 220 } 221 break; 222 223 case HCI_EVENT_DISCONNECTION_COMPLETE: 224 // check handle 225 con_handle = hci_event_disconnection_complete_get_connection_handle(packet); 226 att_server = att_server_for_handle(con_handle); 227 if (!att_server) break; 228 att_clear_transaction_queue(&att_server->connection); 229 att_server->connection.con_handle = 0; 230 att_server->value_indication_handle = 0; // reset error state 231 att_server->pairing_active = 0; 232 att_server->state = ATT_SERVER_IDLE; 233 break; 234 235 // Identity Resolving 236 case SM_EVENT_IDENTITY_RESOLVING_STARTED: 237 con_handle = sm_event_identity_resolving_started_get_handle(packet); 238 att_server = att_server_for_handle(con_handle); 239 if (!att_server) break; 240 log_info("SM_EVENT_IDENTITY_RESOLVING_STARTED"); 241 att_server->ir_lookup_active = 1; 242 break; 243 case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED: 244 con_handle = sm_event_identity_created_get_handle(packet); 245 att_server = att_server_for_handle(con_handle); 246 if (!att_server) return; 247 att_server->ir_lookup_active = 0; 248 att_server->ir_le_device_db_index = sm_event_identity_resolving_succeeded_get_index(packet); 249 log_info("SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED"); 250 att_run_for_context(att_server); 251 break; 252 case SM_EVENT_IDENTITY_RESOLVING_FAILED: 253 con_handle = sm_event_identity_resolving_failed_get_handle(packet); 254 att_server = att_server_for_handle(con_handle); 255 if (!att_server) break; 256 log_info("SM_EVENT_IDENTITY_RESOLVING_FAILED"); 257 att_server->ir_lookup_active = 0; 258 att_server->ir_le_device_db_index = -1; 259 att_run_for_context(att_server); 260 break; 261 262 // Pairing started - delete stored CCC values 263 // - assumes pairing indicates either new device or re-pairing, in both cases there should be no stored CCC values 264 // - assumes that all events have the con handle as the first field 265 case SM_EVENT_JUST_WORKS_REQUEST: 266 case SM_EVENT_PASSKEY_DISPLAY_NUMBER: 267 case SM_EVENT_PASSKEY_INPUT_NUMBER: 268 case SM_EVENT_NUMERIC_COMPARISON_REQUEST: 269 con_handle = sm_event_just_works_request_get_handle(packet); 270 att_server = att_server_for_handle(con_handle); 271 if (!att_server) break; 272 att_server->pairing_active = 1; 273 log_info("SM Pairing started"); 274 if (att_server->ir_le_device_db_index < 0) break; 275 att_server_persistent_ccc_clear(att_server); 276 // index not valid anymore 277 att_server->ir_le_device_db_index = -1; 278 break; 279 280 // Bonding completed 281 case SM_EVENT_IDENTITY_CREATED: 282 con_handle = sm_event_identity_created_get_handle(packet); 283 att_server = att_server_for_handle(con_handle); 284 if (!att_server) return; 285 att_server->pairing_active = 0; 286 att_server->ir_le_device_db_index = sm_event_identity_created_get_index(packet); 287 att_run_for_context(att_server); 288 break; 289 290 // Pairing complete (with/without bonding=storing of pairing information) 291 case SM_EVENT_PAIRING_COMPLETE: 292 con_handle = sm_event_pairing_complete_get_handle(packet); 293 att_server = att_server_for_handle(con_handle); 294 if (!att_server) return; 295 att_server->pairing_active = 0; 296 att_run_for_context(att_server); 297 break; 298 299 // Authorization 300 case SM_EVENT_AUTHORIZATION_RESULT: { 301 con_handle = sm_event_authorization_result_get_handle(packet); 302 att_server = att_server_for_handle(con_handle); 303 if (!att_server) break; 304 att_server->connection.authorized = sm_event_authorization_result_get_authorization_result(packet); 305 att_dispatch_server_request_can_send_now_event(con_handle); 306 break; 307 } 308 default: 309 break; 310 } 311 break; 312 default: 313 break; 314 } 315 } 316 317 #ifdef ENABLE_LE_SIGNED_WRITE 318 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){ 319 320 att_server_t * att_server = att_server_for_state(ATT_SERVER_W4_SIGNED_WRITE_VALIDATION); 321 if (!att_server) return; 322 323 uint8_t hash_flipped[8]; 324 reverse_64(hash, hash_flipped); 325 if (memcmp(hash_flipped, &att_server->request_buffer[att_server->request_size-8], 8)){ 326 log_info("ATT Signed Write, invalid signature"); 327 att_server->state = ATT_SERVER_IDLE; 328 return; 329 } 330 log_info("ATT Signed Write, valid signature"); 331 332 // update sequence number 333 uint32_t counter_packet = little_endian_read_32(att_server->request_buffer, att_server->request_size-12); 334 le_device_db_remote_counter_set(att_server->ir_le_device_db_index, counter_packet+1); 335 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 336 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 337 } 338 #endif 339 340 // pre: att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED 341 // pre: can send now 342 // returns: 1 if packet was sent 343 static int att_server_process_validated_request(att_server_t * att_server){ 344 345 l2cap_reserve_packet_buffer(); 346 uint8_t * att_response_buffer = l2cap_get_outgoing_buffer(); 347 uint16_t att_response_size = att_handle_request(&att_server->connection, att_server->request_buffer, att_server->request_size, att_response_buffer); 348 349 #ifdef ENABLE_ATT_DELAYED_READ_RESPONSE 350 if (att_response_size == ATT_READ_RESPONSE_PENDING){ 351 // update state 352 att_server->state = ATT_SERVER_READ_RESPONSE_PENDING; 353 354 // callback with handle ATT_READ_RESPONSE_PENDING 355 att_server_client_read_callback(att_server->connection.con_handle, ATT_READ_RESPONSE_PENDING, 0, NULL, 0); 356 357 // free reserved buffer 358 l2cap_release_packet_buffer(); 359 return 0; 360 } 361 #endif 362 363 // intercept "insufficient authorization" for authenticated connections to allow for user authorization 364 if ((att_response_size >= 4) 365 && (att_response_buffer[0] == ATT_ERROR_RESPONSE) 366 && (att_response_buffer[4] == ATT_ERROR_INSUFFICIENT_AUTHORIZATION) 367 && (att_server->connection.authenticated)){ 368 369 switch (gap_authorization_state(att_server->connection.con_handle)){ 370 case AUTHORIZATION_UNKNOWN: 371 l2cap_release_packet_buffer(); 372 sm_request_pairing(att_server->connection.con_handle); 373 return 0; 374 case AUTHORIZATION_PENDING: 375 l2cap_release_packet_buffer(); 376 return 0; 377 default: 378 break; 379 } 380 } 381 382 att_server->state = ATT_SERVER_IDLE; 383 if (att_response_size == 0) { 384 l2cap_release_packet_buffer(); 385 return 0; 386 } 387 388 l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, att_response_size); 389 390 // notify client about MTU exchange result 391 if (att_response_buffer[0] == ATT_EXCHANGE_MTU_RESPONSE){ 392 att_emit_mtu_event(att_server->connection.con_handle, att_server->connection.mtu); 393 } 394 return 1; 395 } 396 397 #ifdef ENABLE_ATT_DELAYED_READ_RESPONSE 398 int att_server_read_response_ready(hci_con_handle_t con_handle){ 399 att_server_t * att_server = att_server_for_handle(con_handle); 400 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 401 if (att_server->state != ATT_SERVER_READ_RESPONSE_PENDING) return ERROR_CODE_COMMAND_DISALLOWED; 402 403 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 404 att_dispatch_server_request_can_send_now_event(con_handle); 405 return ERROR_CODE_SUCCESS; 406 } 407 #endif 408 409 static void att_run_for_context(att_server_t * att_server){ 410 switch (att_server->state){ 411 case ATT_SERVER_REQUEST_RECEIVED: 412 413 // wait until pairing is complete 414 if (att_server->pairing_active) break; 415 416 #ifdef ENABLE_LE_SIGNED_WRITE 417 if (att_server->request_buffer[0] == ATT_SIGNED_WRITE_COMMAND){ 418 log_info("ATT Signed Write!"); 419 if (!sm_cmac_ready()) { 420 log_info("ATT Signed Write, sm_cmac engine not ready. Abort"); 421 att_server->state = ATT_SERVER_IDLE; 422 return; 423 } 424 if (att_server->request_size < (3 + 12)) { 425 log_info("ATT Signed Write, request to short. Abort."); 426 att_server->state = ATT_SERVER_IDLE; 427 return; 428 } 429 if (att_server->ir_lookup_active){ 430 return; 431 } 432 if (att_server->ir_le_device_db_index < 0){ 433 log_info("ATT Signed Write, CSRK not available"); 434 att_server->state = ATT_SERVER_IDLE; 435 return; 436 } 437 438 // check counter 439 uint32_t counter_packet = little_endian_read_32(att_server->request_buffer, att_server->request_size-12); 440 uint32_t counter_db = le_device_db_remote_counter_get(att_server->ir_le_device_db_index); 441 log_info("ATT Signed Write, DB counter %"PRIu32", packet counter %"PRIu32, counter_db, counter_packet); 442 if (counter_packet < counter_db){ 443 log_info("ATT Signed Write, db reports higher counter, abort"); 444 att_server->state = ATT_SERVER_IDLE; 445 return; 446 } 447 448 // signature is { sequence counter, secure hash } 449 sm_key_t csrk; 450 le_device_db_remote_csrk_get(att_server->ir_le_device_db_index, csrk); 451 att_server->state = ATT_SERVER_W4_SIGNED_WRITE_VALIDATION; 452 log_info("Orig Signature: "); 453 log_info_hexdump( &att_server->request_buffer[att_server->request_size-8], 8); 454 uint16_t attribute_handle = little_endian_read_16(att_server->request_buffer, 1); 455 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); 456 return; 457 } 458 #endif 459 // move on 460 att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED; 461 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 462 break; 463 464 default: 465 break; 466 } 467 } 468 469 static void att_server_handle_can_send_now(void){ 470 471 // NOTE: we get l2cap fixed channel instead of con_handle 472 473 btstack_linked_list_iterator_t it; 474 hci_connections_get_iterator(&it); 475 while(btstack_linked_list_iterator_has_next(&it)){ 476 hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 477 att_server_t * att_server = &connection->att_server; 478 if (att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED){ 479 int sent = att_server_process_validated_request(att_server); 480 if (sent && (att_client_waiting_for_can_send || !btstack_linked_list_empty(&can_send_now_clients))){ 481 att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle); 482 return; 483 } 484 } 485 } 486 487 while (!btstack_linked_list_empty(&can_send_now_clients)){ 488 // handle first client 489 btstack_context_callback_registration_t * client = (btstack_context_callback_registration_t*) can_send_now_clients; 490 hci_con_handle_t con_handle = (uintptr_t) client->context; 491 btstack_linked_list_remove(&can_send_now_clients, (btstack_linked_item_t *) client); 492 client->callback(client->context); 493 494 // request again if needed 495 if (!att_dispatch_server_can_send_now(con_handle)){ 496 if (!btstack_linked_list_empty(&can_send_now_clients) || att_client_waiting_for_can_send){ 497 att_dispatch_server_request_can_send_now_event(con_handle); 498 } 499 return; 500 } 501 } 502 503 if (att_client_waiting_for_can_send){ 504 att_client_waiting_for_can_send = 0; 505 att_emit_can_send_now_event(); 506 } 507 } 508 509 static void att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 510 511 att_server_t * att_server; 512 513 switch (packet_type){ 514 515 case HCI_EVENT_PACKET: 516 switch (packet[0]){ 517 case L2CAP_EVENT_CAN_SEND_NOW: 518 att_server_handle_can_send_now(); 519 break; 520 case ATT_EVENT_MTU_EXCHANGE_COMPLETE: 521 // GATT client has negotiated the mtu for this connection 522 att_server = att_server_for_handle(handle); 523 if (!att_server) break; 524 att_server->connection.mtu = little_endian_read_16(packet, 4); 525 break; 526 default: 527 break; 528 } 529 break; 530 531 case ATT_DATA_PACKET: 532 log_debug("ATT Packet, handle 0x%04x", handle); 533 att_server = att_server_for_handle(handle); 534 if (!att_server) break; 535 536 // handle value indication confirms 537 if (packet[0] == ATT_HANDLE_VALUE_CONFIRMATION && att_server->value_indication_handle){ 538 btstack_run_loop_remove_timer(&att_server->value_indication_timer); 539 uint16_t att_handle = att_server->value_indication_handle; 540 att_server->value_indication_handle = 0; 541 att_handle_value_indication_notify_client(0, att_server->connection.con_handle, att_handle); 542 return; 543 } 544 545 // directly process command 546 // note: signed write cannot be handled directly as authentication needs to be verified 547 if (packet[0] == ATT_WRITE_COMMAND){ 548 att_handle_request(&att_server->connection, packet, size, 0); 549 return; 550 } 551 552 // check size 553 if (size > sizeof(att_server->request_buffer)) { 554 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)); 555 return; 556 } 557 558 // last request still in processing? 559 if (att_server->state != ATT_SERVER_IDLE){ 560 log_info("att_packet_handler: skipping att pdu 0x%02x as server not idle (state %u)", packet[0], att_server->state); 561 return; 562 } 563 564 // store request 565 att_server->state = ATT_SERVER_REQUEST_RECEIVED; 566 att_server->request_size = size; 567 memcpy(att_server->request_buffer, packet, size); 568 569 att_run_for_context(att_server); 570 break; 571 } 572 } 573 574 // --------------------- 575 // persistent CCC writes 576 static uint32_t att_server_persistent_ccc_tag_for_index(uint8_t index){ 577 return 'B' << 24 | 'T' << 16 | 'C' << 8 | index; 578 } 579 580 static void att_server_persistent_ccc_write(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t value){ 581 // lookup att_server instance 582 att_server_t * att_server = att_server_for_handle(con_handle); 583 if (!att_server) return; 584 int le_device_index = att_server->ir_le_device_db_index; 585 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); 586 587 // check if bonded 588 if (le_device_index < 0) return; 589 590 // get btstack_tlv 591 const btstack_tlv_t * tlv_impl = NULL; 592 void * tlv_context; 593 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 594 if (!tlv_impl) return; 595 596 // update ccc tag 597 int index; 598 uint32_t highest_seq_nr = 0; 599 uint32_t lowest_seq_nr = 0; 600 uint32_t tag_for_lowest_seq_nr = 0; 601 uint32_t tag_for_empty = 0; 602 persistent_ccc_entry_t entry; 603 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 604 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 605 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 606 607 // empty/invalid tag 608 if (len != sizeof(persistent_ccc_entry_t)){ 609 tag_for_empty = tag; 610 continue; 611 } 612 // update highest seq nr 613 if (entry.seq_nr > highest_seq_nr){ 614 highest_seq_nr = entry.seq_nr; 615 } 616 // find entry with lowest seq nr 617 if ((tag_for_lowest_seq_nr == 0) || (entry.seq_nr < lowest_seq_nr)){ 618 tag_for_lowest_seq_nr = tag; 619 lowest_seq_nr = entry.seq_nr; 620 } 621 622 if (entry.device_index != le_device_index) continue; 623 if (entry.att_handle != att_handle) continue; 624 625 // found matching entry 626 if (value){ 627 // update 628 if (entry.value == value) { 629 log_info("CCC Index %u: Up-to-date", index); 630 return; 631 } 632 entry.value = value; 633 entry.seq_nr = highest_seq_nr + 1; 634 log_info("CCC Index %u: Store", index); 635 tlv_impl->store_tag(tlv_context, tag, (const uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 636 } else { 637 // delete 638 log_info("CCC Index %u: Delete", index); 639 tlv_impl->delete_tag(tlv_context, tag); 640 } 641 return; 642 } 643 644 log_info("tag_for_empy %"PRIx32", tag_for_lowest_seq_nr %"PRIx32, tag_for_empty, tag_for_lowest_seq_nr); 645 646 if (value == 0){ 647 // done 648 return; 649 } 650 651 uint32_t tag_to_use = 0; 652 if (tag_for_empty){ 653 tag_to_use = tag_for_empty; 654 } else if (tag_for_lowest_seq_nr){ 655 tag_to_use = tag_for_lowest_seq_nr; 656 } else { 657 // should not happen 658 return; 659 } 660 // store ccc tag 661 entry.seq_nr = highest_seq_nr + 1; 662 entry.device_index = le_device_index; 663 entry.att_handle = att_handle; 664 entry.value = value; 665 tlv_impl->store_tag(tlv_context, tag_to_use, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 666 } 667 668 static void att_server_persistent_ccc_clear(att_server_t * att_server){ 669 if (!att_server) return; 670 int le_device_index = att_server->ir_le_device_db_index; 671 log_info("Clear CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index); 672 // check if bonded 673 if (le_device_index < 0) return; 674 // get btstack_tlv 675 const btstack_tlv_t * tlv_impl = NULL; 676 void * tlv_context; 677 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 678 if (!tlv_impl) return; 679 // get all ccc tag 680 int index; 681 persistent_ccc_entry_t entry; 682 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 683 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 684 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 685 if (len != sizeof(persistent_ccc_entry_t)) continue; 686 if (entry.device_index != le_device_index) continue; 687 // delete entry 688 log_info("CCC Index %u: Delete", index); 689 tlv_impl->delete_tag(tlv_context, tag); 690 } 691 } 692 693 static void att_server_persistent_ccc_restore(att_server_t * att_server){ 694 if (!att_server) return; 695 int le_device_index = att_server->ir_le_device_db_index; 696 log_info("Restore CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index); 697 // check if bonded 698 if (le_device_index < 0) return; 699 // get btstack_tlv 700 const btstack_tlv_t * tlv_impl = NULL; 701 void * tlv_context; 702 btstack_tlv_get_instance(&tlv_impl, &tlv_context); 703 if (!tlv_impl) return; 704 // get all ccc tag 705 int index; 706 persistent_ccc_entry_t entry; 707 for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){ 708 uint32_t tag = att_server_persistent_ccc_tag_for_index(index); 709 int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t)); 710 if (len != sizeof(persistent_ccc_entry_t)) continue; 711 if (entry.device_index != le_device_index) continue; 712 // simulate write callback 713 uint16_t attribute_handle = entry.att_handle; 714 uint8_t value[2]; 715 little_endian_store_16(value, 0, entry.value); 716 att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle); 717 if (!callback) continue; 718 log_info("CCC Index %u: Set Attribute handle 0x%04x to value 0x%04x", index, attribute_handle, entry.value ); 719 (*callback)(att_server->connection.con_handle, attribute_handle, ATT_TRANSACTION_MODE_NONE, 0, value, sizeof(value)); 720 } 721 } 722 723 // persistent CCC writes 724 // --------------------- 725 726 // gatt service management 727 static att_service_handler_t * att_service_handler_for_handle(uint16_t handle){ 728 btstack_linked_list_iterator_t it; 729 btstack_linked_list_iterator_init(&it, &service_handlers); 730 while (btstack_linked_list_iterator_has_next(&it)){ 731 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 732 if (handler->start_handle > handle) continue; 733 if (handler->end_handle < handle) continue; 734 return handler; 735 } 736 return NULL; 737 } 738 static att_read_callback_t att_server_read_callback_for_handle(uint16_t handle){ 739 att_service_handler_t * handler = att_service_handler_for_handle(handle); 740 if (handler) return handler->read_callback; 741 return att_server_client_read_callback; 742 } 743 744 static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle){ 745 att_service_handler_t * handler = att_service_handler_for_handle(handle); 746 if (handler) return handler->write_callback; 747 return att_server_client_write_callback; 748 } 749 750 static void att_notify_write_callbacks(hci_con_handle_t con_handle, uint16_t transaction_mode){ 751 // notify all callbacks 752 btstack_linked_list_iterator_t it; 753 btstack_linked_list_iterator_init(&it, &service_handlers); 754 while (btstack_linked_list_iterator_has_next(&it)){ 755 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 756 if (!handler->write_callback) continue; 757 (*handler->write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0); 758 } 759 if (!att_server_client_write_callback) return; 760 (*att_server_client_write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0); 761 } 762 763 // returns first reported error or 0 764 static uint8_t att_validate_prepared_write(hci_con_handle_t con_handle){ 765 btstack_linked_list_iterator_t it; 766 btstack_linked_list_iterator_init(&it, &service_handlers); 767 while (btstack_linked_list_iterator_has_next(&it)){ 768 att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it); 769 if (!handler->write_callback) continue; 770 uint8_t error_code = (*handler->write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0); 771 if (error_code) return error_code; 772 } 773 if (!att_server_client_write_callback) return 0; 774 return (*att_server_client_write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0); 775 } 776 777 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){ 778 att_read_callback_t callback = att_server_read_callback_for_handle(attribute_handle); 779 if (!callback) return 0; 780 return (*callback)(con_handle, attribute_handle, offset, buffer, buffer_size); 781 } 782 783 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){ 784 switch (transaction_mode){ 785 case ATT_TRANSACTION_MODE_VALIDATE: 786 return att_validate_prepared_write(con_handle); 787 case ATT_TRANSACTION_MODE_EXECUTE: 788 case ATT_TRANSACTION_MODE_CANCEL: 789 att_notify_write_callbacks(con_handle, transaction_mode); 790 return 0; 791 default: 792 break; 793 } 794 795 // track CCC writes 796 if (att_is_persistent_ccc(attribute_handle) && offset == 0 && buffer_size == 2){ 797 att_server_persistent_ccc_write(con_handle, attribute_handle, little_endian_read_16(buffer, 0)); 798 } 799 800 att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle); 801 if (!callback) return 0; 802 return (*callback)(con_handle, attribute_handle, transaction_mode, offset, buffer, buffer_size); 803 } 804 805 /** 806 * @brief register read/write callbacks for specific handle range 807 * @param att_service_handler_t 808 */ 809 void att_server_register_service_handler(att_service_handler_t * handler){ 810 if (att_service_handler_for_handle(handler->start_handle) || 811 att_service_handler_for_handle(handler->end_handle)){ 812 log_error("handler for range 0x%04x-0x%04x already registered", handler->start_handle, handler->end_handle); 813 return; 814 } 815 btstack_linked_list_add(&service_handlers, (btstack_linked_item_t*) handler); 816 } 817 818 void att_server_init(uint8_t const * db, att_read_callback_t read_callback, att_write_callback_t write_callback){ 819 820 // store callbacks 821 att_server_client_read_callback = read_callback; 822 att_server_client_write_callback = write_callback; 823 824 // register for HCI Events 825 hci_event_callback_registration.callback = &att_event_packet_handler; 826 hci_add_event_handler(&hci_event_callback_registration); 827 828 // register for SM events 829 sm_event_callback_registration.callback = &att_event_packet_handler; 830 sm_add_event_handler(&sm_event_callback_registration); 831 832 // and L2CAP ATT Server PDUs 833 att_dispatch_register_server(att_packet_handler); 834 835 att_set_db(db); 836 att_set_read_callback(att_server_read_callback); 837 att_set_write_callback(att_server_write_callback); 838 839 } 840 841 void att_server_register_packet_handler(btstack_packet_handler_t handler){ 842 att_client_packet_handler = handler; 843 } 844 845 int att_server_can_send_packet_now(hci_con_handle_t con_handle){ 846 return att_dispatch_server_can_send_now(con_handle); 847 } 848 849 void att_server_request_can_send_now_event(hci_con_handle_t con_handle){ 850 log_debug("att_server_request_can_send_now_event 0x%04x", con_handle); 851 att_client_waiting_for_can_send = 1; 852 att_dispatch_server_request_can_send_now_event(con_handle); 853 } 854 855 void att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){ 856 // check if can send already 857 if (att_dispatch_server_can_send_now(con_handle)){ 858 callback_registration->callback(callback_registration->context); 859 return; 860 } 861 callback_registration->context = (void*)(uintptr_t) con_handle; 862 btstack_linked_list_add_tail(&can_send_now_clients, (btstack_linked_item_t*) callback_registration); 863 att_dispatch_server_request_can_send_now_event(con_handle); 864 } 865 866 int att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t *value, uint16_t value_len){ 867 att_server_t * att_server = att_server_for_handle(con_handle); 868 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 869 870 if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL; 871 872 l2cap_reserve_packet_buffer(); 873 uint8_t * packet_buffer = l2cap_get_outgoing_buffer(); 874 uint16_t size = att_prepare_handle_value_notification(&att_server->connection, attribute_handle, value, value_len, packet_buffer); 875 return l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size); 876 } 877 878 int att_server_indicate(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t *value, uint16_t value_len){ 879 att_server_t * att_server = att_server_for_handle(con_handle); 880 if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; 881 882 if (att_server->value_indication_handle) return ATT_HANDLE_VALUE_INDICATION_IN_PROGRESS; 883 if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL; 884 885 // track indication 886 att_server->value_indication_handle = attribute_handle; 887 btstack_run_loop_set_timer_handler(&att_server->value_indication_timer, att_handle_value_indication_timeout); 888 btstack_run_loop_set_timer(&att_server->value_indication_timer, ATT_TRANSACTION_TIMEOUT_MS); 889 btstack_run_loop_add_timer(&att_server->value_indication_timer); 890 891 l2cap_reserve_packet_buffer(); 892 uint8_t * packet_buffer = l2cap_get_outgoing_buffer(); 893 uint16_t size = att_prepare_handle_value_indication(&att_server->connection, attribute_handle, value, value_len, packet_buffer); 894 l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size); 895 return 0; 896 } 897