1 /******************************************************************************
2 *
3 * Copyright 2014 Google, Inc.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19 #define LOG_TAG "bt_controller"
20
21 #include "device/include/controller.h"
22
23 #include <base/logging.h>
24
25 #include "bt_types.h"
26 #include "btcore/include/event_mask.h"
27 #include "btcore/include/module.h"
28 #include "btcore/include/version.h"
29 #include "hcimsgs.h"
30 #include "osi/include/future.h"
31 #include "stack/include/btm_ble_api.h"
32
33 const bt_event_mask_t BLE_EVENT_MASK = {{0x00, 0x00, 0x00, 0x00, 0x00, 0x02,
34 #if (BLE_PRIVACY_SPT == TRUE)
35 0x1E,
36 #else
37 /* Disable "LE Enhanced Connection
38 Complete" when privacy is off */
39 0x1C,
40 #endif
41 0x7f}};
42
43 const bt_event_mask_t CLASSIC_EVENT_MASK = {HCI_DUMO_EVENT_MASK_EXT};
44
45 // TODO(zachoverflow): factor out into common module
46 const uint8_t SCO_HOST_BUFFER_SIZE = 0xff;
47
48 #define HCI_SUPPORTED_COMMANDS_ARRAY_SIZE 64
49 #define MAX_FEATURES_CLASSIC_PAGE_COUNT 3
50 #define BLE_SUPPORTED_STATES_SIZE 8
51 #define BLE_SUPPORTED_FEATURES_SIZE 8
52 #define MAX_LOCAL_SUPPORTED_CODECS_SIZE 8
53
54 static const hci_t* hci;
55 static const hci_packet_factory_t* packet_factory;
56 static const hci_packet_parser_t* packet_parser;
57
58 static RawAddress address;
59 static bt_version_t bt_version;
60
61 static uint8_t supported_commands[HCI_SUPPORTED_COMMANDS_ARRAY_SIZE];
62 static bt_device_features_t features_classic[MAX_FEATURES_CLASSIC_PAGE_COUNT];
63 static uint8_t last_features_classic_page_index;
64
65 static uint16_t acl_data_size_classic;
66 static uint16_t acl_data_size_ble;
67 static uint16_t acl_buffer_count_classic;
68 static uint8_t acl_buffer_count_ble;
69
70 static uint8_t ble_white_list_size;
71 static uint8_t ble_resolving_list_max_size;
72 static uint8_t ble_supported_states[BLE_SUPPORTED_STATES_SIZE];
73 static bt_device_features_t features_ble;
74 static uint16_t ble_suggested_default_data_length;
75 static uint16_t ble_supported_max_tx_octets;
76 static uint16_t ble_supported_max_tx_time;
77 static uint16_t ble_supported_max_rx_octets;
78 static uint16_t ble_supported_max_rx_time;
79
80 static uint16_t ble_maxium_advertising_data_length;
81 static uint8_t ble_number_of_supported_advertising_sets;
82 static uint8_t local_supported_codecs[MAX_LOCAL_SUPPORTED_CODECS_SIZE];
83 static uint8_t number_of_local_supported_codecs = 0;
84
85 static bool readable;
86 static bool ble_supported;
87 static bool simple_pairing_supported;
88 static bool secure_connections_supported;
89
90 #define AWAIT_COMMAND(command) \
91 static_cast<BT_HDR*>(future_await(hci->transmit_command_futured(command)))
92
93 // Module lifecycle functions
94
start_up(void)95 static future_t* start_up(void) {
96 BT_HDR* response;
97
98 // Send the initial reset command
99 response = AWAIT_COMMAND(packet_factory->make_reset());
100 packet_parser->parse_generic_command_complete(response);
101
102 // Request the classic buffer size next
103 response = AWAIT_COMMAND(packet_factory->make_read_buffer_size());
104 packet_parser->parse_read_buffer_size_response(
105 response, &acl_data_size_classic, &acl_buffer_count_classic);
106
107 // Tell the controller about our buffer sizes and buffer counts next
108 // TODO(zachoverflow): factor this out. eww l2cap contamination. And why just
109 // a hardcoded 10?
110 response = AWAIT_COMMAND(packet_factory->make_host_buffer_size(
111 L2CAP_MTU_SIZE, SCO_HOST_BUFFER_SIZE, L2CAP_HOST_FC_ACL_BUFS, 10));
112
113 packet_parser->parse_generic_command_complete(response);
114
115 // Read the local version info off the controller next, including
116 // information such as manufacturer and supported HCI version
117 response = AWAIT_COMMAND(packet_factory->make_read_local_version_info());
118 packet_parser->parse_read_local_version_info_response(response, &bt_version);
119
120 // Read the bluetooth address off the controller next
121 response = AWAIT_COMMAND(packet_factory->make_read_bd_addr());
122 packet_parser->parse_read_bd_addr_response(response, &address);
123
124 // Request the controller's supported commands next
125 response =
126 AWAIT_COMMAND(packet_factory->make_read_local_supported_commands());
127 packet_parser->parse_read_local_supported_commands_response(
128 response, supported_commands, HCI_SUPPORTED_COMMANDS_ARRAY_SIZE);
129
130 // Read page 0 of the controller features next
131 uint8_t page_number = 0;
132 response = AWAIT_COMMAND(
133 packet_factory->make_read_local_extended_features(page_number));
134 packet_parser->parse_read_local_extended_features_response(
135 response, &page_number, &last_features_classic_page_index,
136 features_classic, MAX_FEATURES_CLASSIC_PAGE_COUNT);
137
138 CHECK(page_number == 0);
139 page_number++;
140
141 // Inform the controller what page 0 features we support, based on what
142 // it told us it supports. We need to do this first before we request the
143 // next page, because the controller's response for page 1 may be
144 // dependent on what we configure from page 0
145 simple_pairing_supported =
146 HCI_SIMPLE_PAIRING_SUPPORTED(features_classic[0].as_array);
147 if (simple_pairing_supported) {
148 response = AWAIT_COMMAND(
149 packet_factory->make_write_simple_pairing_mode(HCI_SP_MODE_ENABLED));
150 packet_parser->parse_generic_command_complete(response);
151 }
152
153 if (HCI_LE_SPT_SUPPORTED(features_classic[0].as_array)) {
154 uint8_t simultaneous_le_host =
155 HCI_SIMUL_LE_BREDR_SUPPORTED(features_classic[0].as_array)
156 ? BTM_BLE_SIMULTANEOUS_HOST
157 : 0;
158 response = AWAIT_COMMAND(packet_factory->make_ble_write_host_support(
159 BTM_BLE_HOST_SUPPORT, simultaneous_le_host));
160
161 packet_parser->parse_generic_command_complete(response);
162
163 // If we modified the BT_HOST_SUPPORT, we will need ext. feat. page 1
164 if (last_features_classic_page_index < 1)
165 last_features_classic_page_index = 1;
166 }
167
168 // Done telling the controller about what page 0 features we support
169 // Request the remaining feature pages
170 while (page_number <= last_features_classic_page_index &&
171 page_number < MAX_FEATURES_CLASSIC_PAGE_COUNT) {
172 response = AWAIT_COMMAND(
173 packet_factory->make_read_local_extended_features(page_number));
174 packet_parser->parse_read_local_extended_features_response(
175 response, &page_number, &last_features_classic_page_index,
176 features_classic, MAX_FEATURES_CLASSIC_PAGE_COUNT);
177
178 page_number++;
179 }
180
181 #if (SC_MODE_INCLUDED == TRUE)
182 secure_connections_supported =
183 HCI_SC_CTRLR_SUPPORTED(features_classic[2].as_array);
184 if (secure_connections_supported) {
185 response = AWAIT_COMMAND(
186 packet_factory->make_write_secure_connections_host_support(
187 HCI_SC_MODE_ENABLED));
188 packet_parser->parse_generic_command_complete(response);
189 }
190 #endif
191
192 ble_supported = last_features_classic_page_index >= 1 &&
193 HCI_LE_HOST_SUPPORTED(features_classic[1].as_array);
194 if (ble_supported) {
195 // Request the ble white list size next
196 response = AWAIT_COMMAND(packet_factory->make_ble_read_white_list_size());
197 packet_parser->parse_ble_read_white_list_size_response(
198 response, &ble_white_list_size);
199
200 // Request the ble buffer size next
201 response = AWAIT_COMMAND(packet_factory->make_ble_read_buffer_size());
202 packet_parser->parse_ble_read_buffer_size_response(
203 response, &acl_data_size_ble, &acl_buffer_count_ble);
204
205 // Response of 0 indicates ble has the same buffer size as classic
206 if (acl_data_size_ble == 0) acl_data_size_ble = acl_data_size_classic;
207
208 // Request the ble supported states next
209 response = AWAIT_COMMAND(packet_factory->make_ble_read_supported_states());
210 packet_parser->parse_ble_read_supported_states_response(
211 response, ble_supported_states, sizeof(ble_supported_states));
212
213 // Request the ble supported features next
214 response =
215 AWAIT_COMMAND(packet_factory->make_ble_read_local_supported_features());
216 packet_parser->parse_ble_read_local_supported_features_response(
217 response, &features_ble);
218
219 if (HCI_LE_ENHANCED_PRIVACY_SUPPORTED(features_ble.as_array)) {
220 response =
221 AWAIT_COMMAND(packet_factory->make_ble_read_resolving_list_size());
222 packet_parser->parse_ble_read_resolving_list_size_response(
223 response, &ble_resolving_list_max_size);
224 }
225
226 if (HCI_LE_DATA_LEN_EXT_SUPPORTED(features_ble.as_array)) {
227 response =
228 AWAIT_COMMAND(packet_factory->make_ble_read_maximum_data_length());
229 packet_parser->parse_ble_read_maximum_data_length_response(
230 response, &ble_supported_max_tx_octets, &ble_supported_max_tx_time,
231 &ble_supported_max_rx_octets, &ble_supported_max_rx_time);
232
233 response = AWAIT_COMMAND(
234 packet_factory->make_ble_read_suggested_default_data_length());
235 packet_parser->parse_ble_read_suggested_default_data_length_response(
236 response, &ble_suggested_default_data_length);
237 }
238
239 if (HCI_LE_EXTENDED_ADVERTISING_SUPPORTED(features_ble.as_array)) {
240 response = AWAIT_COMMAND(
241 packet_factory->make_ble_read_maximum_advertising_data_length());
242 packet_parser->parse_ble_read_maximum_advertising_data_length(
243 response, &ble_maxium_advertising_data_length);
244
245 response = AWAIT_COMMAND(
246 packet_factory->make_ble_read_number_of_supported_advertising_sets());
247 packet_parser->parse_ble_read_number_of_supported_advertising_sets(
248 response, &ble_number_of_supported_advertising_sets);
249 } else {
250 /* If LE Excended Advertising is not supported, use the default value */
251 ble_maxium_advertising_data_length = 31;
252 }
253
254 // Set the ble event mask next
255 response =
256 AWAIT_COMMAND(packet_factory->make_ble_set_event_mask(&BLE_EVENT_MASK));
257 packet_parser->parse_generic_command_complete(response);
258 }
259
260 if (simple_pairing_supported) {
261 response =
262 AWAIT_COMMAND(packet_factory->make_set_event_mask(&CLASSIC_EVENT_MASK));
263 packet_parser->parse_generic_command_complete(response);
264 }
265
266 // read local supported codecs
267 if (HCI_READ_LOCAL_CODECS_SUPPORTED(supported_commands)) {
268 response =
269 AWAIT_COMMAND(packet_factory->make_read_local_supported_codecs());
270 packet_parser->parse_read_local_supported_codecs_response(
271 response, &number_of_local_supported_codecs, local_supported_codecs);
272 }
273
274 if (!HCI_READ_ENCR_KEY_SIZE_SUPPORTED(supported_commands)) {
275 LOG(FATAL) << " Controller must support Read Encryption Key Size command";
276 }
277
278 readable = true;
279 return future_new_immediate(FUTURE_SUCCESS);
280 }
281
shut_down(void)282 static future_t* shut_down(void) {
283 readable = false;
284 return future_new_immediate(FUTURE_SUCCESS);
285 }
286
287 EXPORT_SYMBOL extern const module_t controller_module = {
288 .name = CONTROLLER_MODULE,
289 .init = NULL,
290 .start_up = start_up,
291 .shut_down = shut_down,
292 .clean_up = NULL,
293 .dependencies = {HCI_MODULE, NULL}};
294
295 // Interface functions
296
get_is_ready(void)297 static bool get_is_ready(void) { return readable; }
298
get_address(void)299 static const RawAddress* get_address(void) {
300 CHECK(readable);
301 return &address;
302 }
303
get_bt_version(void)304 static const bt_version_t* get_bt_version(void) {
305 CHECK(readable);
306 return &bt_version;
307 }
308
309 // TODO(zachoverflow): hide inside, move decoder inside too
get_features_classic(int index)310 static const bt_device_features_t* get_features_classic(int index) {
311 CHECK(readable);
312 CHECK(index < MAX_FEATURES_CLASSIC_PAGE_COUNT);
313 return &features_classic[index];
314 }
315
get_last_features_classic_index(void)316 static uint8_t get_last_features_classic_index(void) {
317 CHECK(readable);
318 return last_features_classic_page_index;
319 }
320
get_local_supported_codecs(uint8_t * number_of_codecs)321 static uint8_t* get_local_supported_codecs(uint8_t* number_of_codecs) {
322 CHECK(readable);
323 if (number_of_local_supported_codecs) {
324 *number_of_codecs = number_of_local_supported_codecs;
325 return local_supported_codecs;
326 }
327 return NULL;
328 }
329
get_features_ble(void)330 static const bt_device_features_t* get_features_ble(void) {
331 CHECK(readable);
332 CHECK(ble_supported);
333 return &features_ble;
334 }
335
get_ble_supported_states(void)336 static const uint8_t* get_ble_supported_states(void) {
337 CHECK(readable);
338 CHECK(ble_supported);
339 return ble_supported_states;
340 }
341
supports_simple_pairing(void)342 static bool supports_simple_pairing(void) {
343 CHECK(readable);
344 return simple_pairing_supported;
345 }
346
supports_secure_connections(void)347 static bool supports_secure_connections(void) {
348 CHECK(readable);
349 return secure_connections_supported;
350 }
351
supports_simultaneous_le_bredr(void)352 static bool supports_simultaneous_le_bredr(void) {
353 CHECK(readable);
354 return HCI_SIMUL_LE_BREDR_SUPPORTED(features_classic[0].as_array);
355 }
356
supports_reading_remote_extended_features(void)357 static bool supports_reading_remote_extended_features(void) {
358 CHECK(readable);
359 return HCI_READ_REMOTE_EXT_FEATURES_SUPPORTED(supported_commands);
360 }
361
supports_interlaced_inquiry_scan(void)362 static bool supports_interlaced_inquiry_scan(void) {
363 CHECK(readable);
364 return HCI_LMP_INTERLACED_INQ_SCAN_SUPPORTED(features_classic[0].as_array);
365 }
366
supports_rssi_with_inquiry_results(void)367 static bool supports_rssi_with_inquiry_results(void) {
368 CHECK(readable);
369 return HCI_LMP_INQ_RSSI_SUPPORTED(features_classic[0].as_array);
370 }
371
supports_extended_inquiry_response(void)372 static bool supports_extended_inquiry_response(void) {
373 CHECK(readable);
374 return HCI_EXT_INQ_RSP_SUPPORTED(features_classic[0].as_array);
375 }
376
supports_master_slave_role_switch(void)377 static bool supports_master_slave_role_switch(void) {
378 CHECK(readable);
379 return HCI_SWITCH_SUPPORTED(features_classic[0].as_array);
380 }
381
supports_enhanced_setup_synchronous_connection(void)382 static bool supports_enhanced_setup_synchronous_connection(void) {
383 assert(readable);
384 return HCI_ENH_SETUP_SYNCH_CONN_SUPPORTED(supported_commands);
385 }
386
supports_enhanced_accept_synchronous_connection(void)387 static bool supports_enhanced_accept_synchronous_connection(void) {
388 assert(readable);
389 return HCI_ENH_ACCEPT_SYNCH_CONN_SUPPORTED(supported_commands);
390 }
391
supports_ble(void)392 static bool supports_ble(void) {
393 CHECK(readable);
394 return ble_supported;
395 }
396
supports_ble_privacy(void)397 static bool supports_ble_privacy(void) {
398 CHECK(readable);
399 CHECK(ble_supported);
400 return HCI_LE_ENHANCED_PRIVACY_SUPPORTED(features_ble.as_array);
401 }
402
supports_ble_set_privacy_mode()403 static bool supports_ble_set_privacy_mode() {
404 CHECK(readable);
405 CHECK(ble_supported);
406 return HCI_LE_ENHANCED_PRIVACY_SUPPORTED(features_ble.as_array) &&
407 HCI_LE_SET_PRIVACY_MODE_SUPPORTED(supported_commands);
408 }
409
supports_ble_packet_extension(void)410 static bool supports_ble_packet_extension(void) {
411 CHECK(readable);
412 CHECK(ble_supported);
413 return HCI_LE_DATA_LEN_EXT_SUPPORTED(features_ble.as_array);
414 }
415
supports_ble_connection_parameters_request(void)416 static bool supports_ble_connection_parameters_request(void) {
417 CHECK(readable);
418 CHECK(ble_supported);
419 return HCI_LE_CONN_PARAM_REQ_SUPPORTED(features_ble.as_array);
420 }
421
supports_ble_2m_phy(void)422 static bool supports_ble_2m_phy(void) {
423 CHECK(readable);
424 CHECK(ble_supported);
425 return HCI_LE_2M_PHY_SUPPORTED(features_ble.as_array);
426 }
427
supports_ble_coded_phy(void)428 static bool supports_ble_coded_phy(void) {
429 CHECK(readable);
430 CHECK(ble_supported);
431 return HCI_LE_CODED_PHY_SUPPORTED(features_ble.as_array);
432 }
433
supports_ble_extended_advertising(void)434 static bool supports_ble_extended_advertising(void) {
435 CHECK(readable);
436 CHECK(ble_supported);
437 return HCI_LE_EXTENDED_ADVERTISING_SUPPORTED(features_ble.as_array);
438 }
439
supports_ble_periodic_advertising(void)440 static bool supports_ble_periodic_advertising(void) {
441 CHECK(readable);
442 CHECK(ble_supported);
443 return HCI_LE_PERIODIC_ADVERTISING_SUPPORTED(features_ble.as_array);
444 }
445
get_acl_data_size_classic(void)446 static uint16_t get_acl_data_size_classic(void) {
447 CHECK(readable);
448 return acl_data_size_classic;
449 }
450
get_acl_data_size_ble(void)451 static uint16_t get_acl_data_size_ble(void) {
452 CHECK(readable);
453 CHECK(ble_supported);
454 return acl_data_size_ble;
455 }
456
get_acl_packet_size_classic(void)457 static uint16_t get_acl_packet_size_classic(void) {
458 CHECK(readable);
459 return acl_data_size_classic + HCI_DATA_PREAMBLE_SIZE;
460 }
461
get_acl_packet_size_ble(void)462 static uint16_t get_acl_packet_size_ble(void) {
463 CHECK(readable);
464 return acl_data_size_ble + HCI_DATA_PREAMBLE_SIZE;
465 }
466
get_ble_suggested_default_data_length(void)467 static uint16_t get_ble_suggested_default_data_length(void) {
468 CHECK(readable);
469 CHECK(ble_supported);
470 return ble_suggested_default_data_length;
471 }
472
get_ble_maximum_tx_data_length(void)473 static uint16_t get_ble_maximum_tx_data_length(void) {
474 CHECK(readable);
475 CHECK(ble_supported);
476 return ble_supported_max_tx_octets;
477 }
478
get_ble_maxium_advertising_data_length(void)479 static uint16_t get_ble_maxium_advertising_data_length(void) {
480 CHECK(readable);
481 CHECK(ble_supported);
482 return ble_maxium_advertising_data_length;
483 }
484
get_ble_number_of_supported_advertising_sets(void)485 static uint8_t get_ble_number_of_supported_advertising_sets(void) {
486 CHECK(readable);
487 CHECK(ble_supported);
488 return ble_number_of_supported_advertising_sets;
489 }
490
get_acl_buffer_count_classic(void)491 static uint16_t get_acl_buffer_count_classic(void) {
492 CHECK(readable);
493 return acl_buffer_count_classic;
494 }
495
get_acl_buffer_count_ble(void)496 static uint8_t get_acl_buffer_count_ble(void) {
497 CHECK(readable);
498 CHECK(ble_supported);
499 return acl_buffer_count_ble;
500 }
501
get_ble_white_list_size(void)502 static uint8_t get_ble_white_list_size(void) {
503 CHECK(readable);
504 CHECK(ble_supported);
505 return ble_white_list_size;
506 }
507
get_ble_resolving_list_max_size(void)508 static uint8_t get_ble_resolving_list_max_size(void) {
509 CHECK(readable);
510 CHECK(ble_supported);
511 return ble_resolving_list_max_size;
512 }
513
set_ble_resolving_list_max_size(int resolving_list_max_size)514 static void set_ble_resolving_list_max_size(int resolving_list_max_size) {
515 // Setting "resolving_list_max_size" to 0 is done during cleanup,
516 // hence we ignore the "readable" flag already set to false during shutdown.
517 if (resolving_list_max_size != 0) {
518 CHECK(readable);
519 }
520 CHECK(ble_supported);
521 ble_resolving_list_max_size = resolving_list_max_size;
522 }
523
get_le_all_initiating_phys()524 static uint8_t get_le_all_initiating_phys() {
525 uint8_t phy = PHY_LE_1M;
526 // TODO(jpawlowski): uncomment after next FW udpate
527 // if (supports_ble_2m_phy()) phy |= PHY_LE_2M;
528 // if (supports_ble_coded_phy()) phy |= PHY_LE_CODED;
529 return phy;
530 }
531
532 static const controller_t interface = {
533 get_is_ready,
534
535 get_address,
536 get_bt_version,
537
538 get_features_classic,
539 get_last_features_classic_index,
540
541 get_features_ble,
542 get_ble_supported_states,
543
544 supports_simple_pairing,
545 supports_secure_connections,
546 supports_simultaneous_le_bredr,
547 supports_reading_remote_extended_features,
548 supports_interlaced_inquiry_scan,
549 supports_rssi_with_inquiry_results,
550 supports_extended_inquiry_response,
551 supports_master_slave_role_switch,
552 supports_enhanced_setup_synchronous_connection,
553 supports_enhanced_accept_synchronous_connection,
554
555 supports_ble,
556 supports_ble_packet_extension,
557 supports_ble_connection_parameters_request,
558 supports_ble_privacy,
559 supports_ble_set_privacy_mode,
560 supports_ble_2m_phy,
561 supports_ble_coded_phy,
562 supports_ble_extended_advertising,
563 supports_ble_periodic_advertising,
564
565 get_acl_data_size_classic,
566 get_acl_data_size_ble,
567
568 get_acl_packet_size_classic,
569 get_acl_packet_size_ble,
570 get_ble_suggested_default_data_length,
571 get_ble_maximum_tx_data_length,
572 get_ble_maxium_advertising_data_length,
573 get_ble_number_of_supported_advertising_sets,
574
575 get_acl_buffer_count_classic,
576 get_acl_buffer_count_ble,
577
578 get_ble_white_list_size,
579
580 get_ble_resolving_list_max_size,
581 set_ble_resolving_list_max_size,
582 get_local_supported_codecs,
583 get_le_all_initiating_phys};
584
controller_get_interface()585 const controller_t* controller_get_interface() {
586 static bool loaded = false;
587 if (!loaded) {
588 loaded = true;
589
590 hci = hci_layer_get_interface();
591 packet_factory = hci_packet_factory_get_interface();
592 packet_parser = hci_packet_parser_get_interface();
593 }
594
595 return &interface;
596 }
597
controller_get_test_interface(const hci_t * hci_interface,const hci_packet_factory_t * packet_factory_interface,const hci_packet_parser_t * packet_parser_interface)598 const controller_t* controller_get_test_interface(
599 const hci_t* hci_interface,
600 const hci_packet_factory_t* packet_factory_interface,
601 const hci_packet_parser_t* packet_parser_interface) {
602 hci = hci_interface;
603 packet_factory = packet_factory_interface;
604 packet_parser = packet_parser_interface;
605 return &interface;
606 }
607