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