xref: /btstack/src/hci.c (revision 7dc179430c68ffb28dc3dc6fa20aa951bd4fa56e)
1 /*
2  * Copyright (C) 2009 by Matthias Ringwald
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  *
17  * THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
20  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
21  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
23  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
24  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
25  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
27  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  */
31 
32 /*
33  *  hci.c
34  *
35  *  Created by Matthias Ringwald on 4/29/09.
36  *
37  */
38 
39 #include "hci.h"
40 
41 #include <stdarg.h>
42 #include <string.h>
43 #include <stdio.h>
44 
45 #ifndef EMBEDDED
46 #include <unistd.h> // gethostbyname
47 #endif
48 
49 #include "btstack_memory.h"
50 #include "debug.h"
51 #include "hci_dump.h"
52 
53 #include <btstack/hci_cmds.h>
54 #include <btstack/version.h>
55 
56 // tmpe
57 #include "l2cap.h"
58 
59 #define HCI_CONNECTION_TIMEOUT_MS 10000
60 
61 // the STACK is here
62 static hci_stack_t       hci_stack;
63 
64 /**
65  * get connection for a given handle
66  *
67  * @return connection OR NULL, if not found
68  */
69 hci_connection_t * connection_for_handle(hci_con_handle_t con_handle){
70     linked_item_t *it;
71     for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
72         if ( ((hci_connection_t *) it)->con_handle == con_handle){
73             return (hci_connection_t *) it;
74         }
75     }
76     return NULL;
77 }
78 
79 static void hci_connection_timeout_handler(timer_source_t *timer){
80     hci_connection_t * connection = linked_item_get_user(&timer->item);
81 #ifdef HAVE_TIME
82     struct timeval tv;
83     gettimeofday(&tv, NULL);
84     if (tv.tv_sec >= connection->timestamp.tv_sec + HCI_CONNECTION_TIMEOUT_MS/1000) {
85         // connections might be timed out
86         hci_emit_l2cap_check_timeout(connection);
87     }
88 #endif
89 #ifdef EMBEDDED
90     if (embedded_get_ticks() > connection->timestamp + embedded_ticks_for_ms(HCI_CONNECTION_TIMEOUT_MS)){
91         // connections might be timed out
92         hci_emit_l2cap_check_timeout(connection);
93     }
94 #endif
95     run_loop_set_timer(timer, HCI_CONNECTION_TIMEOUT_MS);
96     run_loop_add_timer(timer);
97 }
98 
99 static void hci_connection_timestamp(hci_connection_t *connection){
100 #ifdef HAVE_TIME
101     gettimeofday(&connection->timestamp, NULL);
102 #endif
103 #ifdef EMBEDDED
104     connection->timestamp = embedded_get_ticks();
105 #endif
106 }
107 
108 /**
109  * create connection for given address
110  *
111  * @return connection OR NULL, if no memory left
112  */
113 static hci_connection_t * create_connection_for_addr(bd_addr_t addr){
114     hci_connection_t * conn = btstack_memory_hci_connection_get();
115     if (!conn) return NULL;
116     BD_ADDR_COPY(conn->address, addr);
117     conn->con_handle = 0xffff;
118     conn->authentication_flags = AUTH_FLAGS_NONE;
119     linked_item_set_user(&conn->timeout.item, conn);
120     conn->timeout.process = hci_connection_timeout_handler;
121     hci_connection_timestamp(conn);
122     conn->acl_recombination_length = 0;
123     conn->acl_recombination_pos = 0;
124     conn->num_acl_packets_sent = 0;
125     linked_list_add(&hci_stack.connections, (linked_item_t *) conn);
126     return conn;
127 }
128 
129 /**
130  * get connection for given address
131  *
132  * @return connection OR NULL, if not found
133  */
134 static hci_connection_t * connection_for_address(bd_addr_t address){
135     linked_item_t *it;
136     for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
137         if ( ! BD_ADDR_CMP( ((hci_connection_t *) it)->address, address) ){
138             return (hci_connection_t *) it;
139         }
140     }
141     return NULL;
142 }
143 
144 /**
145  * add authentication flags and reset timer
146  */
147 static void hci_add_connection_flags_for_flipped_bd_addr(uint8_t *bd_addr, hci_authentication_flags_t flags){
148     bd_addr_t addr;
149     bt_flip_addr(addr, *(bd_addr_t *) bd_addr);
150     hci_connection_t * conn = connection_for_address(addr);
151     if (conn) {
152         conn->authentication_flags |= flags;
153         hci_connection_timestamp(conn);
154     }
155 }
156 
157 int  hci_authentication_active_for_handle(hci_con_handle_t handle){
158     hci_connection_t * conn = connection_for_handle(handle);
159     if (!conn) return 0;
160     if (!conn->authentication_flags) return 0;
161     if (conn->authentication_flags & SENT_LINK_KEY_REPLY) return 0;
162     if (conn->authentication_flags & RECV_LINK_KEY_NOTIFICATION) return 0;
163     return 1;
164 }
165 
166 void hci_drop_link_key_for_bd_addr(bd_addr_t *addr){
167     if (hci_stack.remote_device_db) {
168         hci_stack.remote_device_db->delete_link_key(addr);
169     }
170 }
171 
172 
173 /**
174  * count connections
175  */
176 static int nr_hci_connections(void){
177     int count = 0;
178     linked_item_t *it;
179     for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next, count++);
180     return count;
181 }
182 
183 /**
184  * Dummy handler called by HCI
185  */
186 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
187 }
188 
189 uint8_t hci_number_outgoing_packets(hci_con_handle_t handle){
190     hci_connection_t * connection = connection_for_handle(handle);
191     if (!connection) {
192         log_error("hci_number_outgoing_packets connectino for handle %u does not exist!\n", handle);
193         return 0;
194     }
195     return connection->num_acl_packets_sent;
196 }
197 
198 uint8_t hci_number_free_acl_slots(){
199     uint8_t free_slots = hci_stack.total_num_acl_packets;
200     linked_item_t *it;
201     for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
202         hci_connection_t * connection = (hci_connection_t *) it;
203         if (free_slots < connection->num_acl_packets_sent) {
204             log_error("hci_number_free_acl_slots: sum of outgoing packets > total acl packets!\n");
205             return 0;
206         }
207         free_slots -= connection->num_acl_packets_sent;
208     }
209     return free_slots;
210 }
211 
212 int hci_can_send_packet_now(uint8_t packet_type){
213 
214     // check for async hci transport implementations
215     if (hci_stack.hci_transport->can_send_packet_now){
216         if (!hci_stack.hci_transport->can_send_packet_now(packet_type)){
217             return 0;
218         }
219     }
220 
221     // check regular Bluetooth flow control
222     switch (packet_type) {
223         case HCI_ACL_DATA_PACKET:
224             return hci_number_free_acl_slots();
225         case HCI_COMMAND_DATA_PACKET:
226             return hci_stack.num_cmd_packets;
227         default:
228             return 0;
229     }
230 }
231 
232 int hci_send_acl_packet(uint8_t *packet, int size){
233 
234     // check for free places on BT module
235     if (!hci_number_free_acl_slots()) return BTSTACK_ACL_BUFFERS_FULL;
236 
237     hci_con_handle_t con_handle = READ_ACL_CONNECTION_HANDLE(packet);
238     hci_connection_t *connection = connection_for_handle( con_handle);
239     if (!connection) return 0;
240     hci_connection_timestamp(connection);
241 
242     // count packet
243     connection->num_acl_packets_sent++;
244     // log_info("hci_send_acl_packet - handle %u, sent %u\n", connection->con_handle, connection->num_acl_packets_sent);
245 
246     // send packet - ignore errors
247     hci_stack.hci_transport->send_packet(HCI_ACL_DATA_PACKET, packet, size);
248 
249     return 0;
250 }
251 
252 static void acl_handler(uint8_t *packet, int size){
253 
254     // get info
255     hci_con_handle_t con_handle = READ_ACL_CONNECTION_HANDLE(packet);
256     hci_connection_t *conn      = connection_for_handle(con_handle);
257     uint8_t  acl_flags          = READ_ACL_FLAGS(packet);
258     uint16_t acl_length         = READ_ACL_LENGTH(packet);
259 
260     // ignore non-registered handle
261     if (!conn){
262         log_error( "hci.c: acl_handler called with non-registered handle %u!\n" , con_handle);
263         return;
264     }
265 
266     // update idle timestamp
267     hci_connection_timestamp(conn);
268 
269     // handle different packet types
270     switch (acl_flags & 0x03) {
271 
272         case 0x01: // continuation fragment
273 
274             // sanity check
275             if (conn->acl_recombination_pos == 0) {
276                 log_error( "ACL Cont Fragment but no first fragment for handle 0x%02x\n", con_handle);
277                 return;
278             }
279 
280             // append fragment payload (header already stored)
281             memcpy(&conn->acl_recombination_buffer[conn->acl_recombination_pos], &packet[4], acl_length );
282             conn->acl_recombination_pos += acl_length;
283 
284             // log_error( "ACL Cont Fragment: acl_len %u, combined_len %u, l2cap_len %u\n", acl_length,
285             //        conn->acl_recombination_pos, conn->acl_recombination_length);
286 
287             // forward complete L2CAP packet if complete.
288             if (conn->acl_recombination_pos >= conn->acl_recombination_length + 4 + 4){ // pos already incl. ACL header
289 
290                 hci_stack.packet_handler(HCI_ACL_DATA_PACKET, conn->acl_recombination_buffer, conn->acl_recombination_pos);
291                 // reset recombination buffer
292                 conn->acl_recombination_length = 0;
293                 conn->acl_recombination_pos = 0;
294             }
295             break;
296 
297         case 0x02: { // first fragment
298 
299             // sanity check
300             if (conn->acl_recombination_pos) {
301                 log_error( "ACL First Fragment but data in buffer for handle 0x%02x\n", con_handle);
302                 return;
303             }
304 
305             // peek into L2CAP packet!
306             uint16_t l2cap_length = READ_L2CAP_LENGTH( packet );
307 
308             // log_error( "ACL First Fragment: acl_len %u, l2cap_len %u\n", acl_length, l2cap_length);
309 
310             // compare fragment size to L2CAP packet size
311             if (acl_length >= l2cap_length + 4){
312 
313                 // forward fragment as L2CAP packet
314                 hci_stack.packet_handler(HCI_ACL_DATA_PACKET, packet, acl_length + 4);
315 
316             } else {
317                 // store first fragment and tweak acl length for complete package
318                 memcpy(conn->acl_recombination_buffer, packet, acl_length + 4);
319                 conn->acl_recombination_pos    = acl_length + 4;
320                 conn->acl_recombination_length = l2cap_length;
321                 bt_store_16(conn->acl_recombination_buffer, 2, l2cap_length +4);
322             }
323             break;
324 
325         }
326         default:
327             log_error( "hci.c: acl_handler called with invalid packet boundary flags %u\n", acl_flags & 0x03);
328             return;
329     }
330 
331     // execute main loop
332     hci_run();
333 }
334 
335 static void hci_shutdown_connection(hci_connection_t *conn){
336     log_info("Connection closed: handle %u, %s\n", conn->con_handle, bd_addr_to_str(conn->address));
337 
338     // cancel all l2cap connections
339     hci_emit_disconnection_complete(conn->con_handle, 0x16);    // terminated by local host
340 
341     run_loop_remove_timer(&conn->timeout);
342 
343     linked_list_remove(&hci_stack.connections, (linked_item_t *) conn);
344     btstack_memory_hci_connection_free( conn );
345 
346     // now it's gone
347     hci_emit_nr_connections_changed();
348 }
349 
350 static uint16_t packet_type_sizes[] = {
351     0, HCI_ACL_2DH1_SIZE, HCI_ACL_3DH1_SIZE, HCI_ACL_DM1_SIZE,
352     HCI_ACL_DH1_SIZE, 0, 0, 0,
353     HCI_ACL_2DH3_SIZE, HCI_ACL_3DH3_SIZE, HCI_ACL_DM3_SIZE, HCI_ACL_DH3_SIZE,
354     HCI_ACL_2DH5_SIZE, HCI_ACL_3DH5_SIZE, HCI_ACL_DM5_SIZE, HCI_ACL_DH5_SIZE
355 };
356 
357 static uint16_t hci_acl_packet_types_for_buffer_size(uint16_t buffer_size){
358     uint16_t packet_types = 0;
359     int i;
360     for (i=0;i<16;i++){
361         if (packet_type_sizes[i] == 0) continue;
362         if (packet_type_sizes[i] <= buffer_size){
363             packet_types |= 1 << i;
364         }
365     }
366     // flip bits for "may not be used"
367     packet_types ^= 0x3306;
368     return packet_types;
369 }
370 
371 uint16_t hci_usable_acl_packet_types(void){
372     return hci_stack.packet_types;
373 }
374 
375 uint8_t* hci_get_outgoing_acl_packet_buffer(void){
376     // hci packet buffer is >= acl data packet length
377     return hci_stack.hci_packet_buffer;
378 }
379 
380 uint16_t hci_max_acl_data_packet_length(){
381     return hci_stack.acl_data_packet_length;
382 }
383 
384 // avoid huge local variables
385 #ifndef EMBEDDED
386 static device_name_t device_name;
387 #endif
388 static void event_handler(uint8_t *packet, int size){
389     bd_addr_t addr;
390     uint8_t link_type;
391     hci_con_handle_t handle;
392     hci_connection_t * conn;
393     int i;
394 
395     switch (packet[0]) {
396 
397         case HCI_EVENT_COMMAND_COMPLETE:
398             // get num cmd packets
399             // log_info("HCI_EVENT_COMMAND_COMPLETE cmds old %u - new %u\n", hci_stack.num_cmd_packets, packet[2]);
400             hci_stack.num_cmd_packets = packet[2];
401 
402             if (COMMAND_COMPLETE_EVENT(packet, hci_read_buffer_size)){
403                 // from offset 5
404                 // status
405                 // "The HC_ACL_Data_Packet_Length return parameter will be used to determine the size of the L2CAP segments contained in ACL Data Packets"
406                 hci_stack.acl_data_packet_length = READ_BT_16(packet, 6);
407                 // ignore: SCO data packet len (8)
408                 hci_stack.total_num_acl_packets  = packet[9];
409                 // ignore: total num SCO packets
410                 if (hci_stack.state == HCI_STATE_INITIALIZING){
411                     // determine usable ACL payload size
412                     if (HCI_ACL_BUFFER_SIZE < hci_stack.acl_data_packet_length){
413                         hci_stack.acl_data_packet_length = HCI_ACL_BUFFER_SIZE;
414                     }
415                     // determine usable ACL packet types
416                     hci_stack.packet_types = hci_acl_packet_types_for_buffer_size(hci_stack.acl_data_packet_length);
417 
418                     log_error("hci_read_buffer_size: size %u, count %u, packet types %04x\n",
419                              hci_stack.acl_data_packet_length, hci_stack.total_num_acl_packets, hci_stack.packet_types);
420                 }
421             }
422             if (COMMAND_COMPLETE_EVENT(packet, hci_write_scan_enable)){
423                 hci_emit_discoverable_enabled(hci_stack.discoverable);
424             }
425             break;
426 
427         case HCI_EVENT_COMMAND_STATUS:
428             // get num cmd packets
429             // log_info("HCI_EVENT_COMMAND_STATUS cmds - old %u - new %u\n", hci_stack.num_cmd_packets, packet[3]);
430             hci_stack.num_cmd_packets = packet[3];
431             break;
432 
433         case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS:
434             for (i=0; i<packet[2];i++){
435                 handle = READ_BT_16(packet, 3 + 2*i);
436                 uint16_t num_packets = READ_BT_16(packet, 3 + packet[2]*2 + 2*i);
437                 conn = connection_for_handle(handle);
438                 if (!conn){
439                     log_error("hci_number_completed_packet lists unused con handle %u\n", handle);
440                     continue;
441                 }
442                 conn->num_acl_packets_sent -= num_packets;
443                 // log_info("hci_number_completed_packet %u processed for handle %u, outstanding %u\n", num_packets, handle, conn->num_acl_packets_sent);
444             }
445             break;
446 
447         case HCI_EVENT_CONNECTION_REQUEST:
448             bt_flip_addr(addr, &packet[2]);
449             // TODO: eval COD 8-10
450             link_type = packet[11];
451             log_info("Connection_incoming: %s, type %u\n", bd_addr_to_str(addr), link_type);
452             if (link_type == 1) { // ACL
453                 conn = connection_for_address(addr);
454                 if (!conn) {
455                     conn = create_connection_for_addr(addr);
456                 }
457                 if (!conn) {
458                     // CONNECTION REJECTED DUE TO LIMITED RESOURCES (0X0D)
459                     hci_stack.decline_reason = 0x0d;
460                     BD_ADDR_COPY(hci_stack.decline_addr, addr);
461                     break;
462                 }
463                 conn->state = RECEIVED_CONNECTION_REQUEST;
464                 hci_run();
465             } else {
466                 // SYNCHRONOUS CONNECTION LIMIT TO A DEVICE EXCEEDED (0X0A)
467                 hci_stack.decline_reason = 0x0a;
468                 BD_ADDR_COPY(hci_stack.decline_addr, addr);
469             }
470             break;
471 
472         case HCI_EVENT_CONNECTION_COMPLETE:
473             // Connection management
474             bt_flip_addr(addr, &packet[5]);
475             log_info("Connection_complete (status=%u) %s\n", packet[2], bd_addr_to_str(addr));
476             conn = connection_for_address(addr);
477             if (conn) {
478                 if (!packet[2]){
479                     conn->state = OPEN;
480                     conn->con_handle = READ_BT_16(packet, 3);
481 
482                     // restart timer
483                     run_loop_set_timer(&conn->timeout, HCI_CONNECTION_TIMEOUT_MS);
484                     run_loop_add_timer(&conn->timeout);
485 
486                     log_info("New connection: handle %u, %s\n", conn->con_handle, bd_addr_to_str(conn->address));
487 
488                     hci_emit_nr_connections_changed();
489                 } else {
490                     // connection failed, remove entry
491                     linked_list_remove(&hci_stack.connections, (linked_item_t *) conn);
492                     btstack_memory_hci_connection_free( conn );
493 
494                     // if authentication error, also delete link key
495                     if (packet[2] == 0x05) {
496                         hci_drop_link_key_for_bd_addr(&addr);
497                     }
498                 }
499             }
500             break;
501 
502         case HCI_EVENT_LINK_KEY_REQUEST:
503             log_info("HCI_EVENT_LINK_KEY_REQUEST\n");
504             hci_add_connection_flags_for_flipped_bd_addr(&packet[2], RECV_LINK_KEY_REQUEST);
505             if (!hci_stack.remote_device_db) break;
506             hci_add_connection_flags_for_flipped_bd_addr(&packet[2], HANDLE_LINK_KEY_REQUEST);
507             hci_run();
508             // request already answered
509             return;
510 
511         case HCI_EVENT_LINK_KEY_NOTIFICATION:
512             hci_add_connection_flags_for_flipped_bd_addr(&packet[2], RECV_LINK_KEY_NOTIFICATION);
513             if (!hci_stack.remote_device_db) break;
514             bt_flip_addr(addr, &packet[2]);
515             hci_stack.remote_device_db->put_link_key(&addr, (link_key_t *) &packet[8]);
516             // still forward event to allow dismiss of pairing dialog
517             break;
518 
519         case HCI_EVENT_PIN_CODE_REQUEST:
520             hci_add_connection_flags_for_flipped_bd_addr(&packet[2], RECV_PIN_CODE_REQUEST);
521             break;
522 
523 #ifndef EMBEDDED
524         case HCI_EVENT_REMOTE_NAME_REQUEST_COMPLETE:
525             if (!hci_stack.remote_device_db) break;
526             if (packet[2]) break; // status not ok
527             bt_flip_addr(addr, &packet[3]);
528             // fix for invalid remote names - terminate on 0xff
529             for (i=0; i<248;i++){
530                 if (packet[9+i] == 0xff){
531                     packet[9+i] = 0;
532                     break;
533                 }
534             }
535             bzero(&device_name, sizeof(device_name_t));
536             strncpy((char*) device_name, (char*) &packet[9], 248);
537             hci_stack.remote_device_db->put_name(&addr, &device_name);
538             break;
539 
540         case HCI_EVENT_INQUIRY_RESULT:
541         case HCI_EVENT_INQUIRY_RESULT_WITH_RSSI:
542             if (!hci_stack.remote_device_db) break;
543             // first send inq result packet
544             hci_stack.packet_handler(HCI_EVENT_PACKET, packet, size);
545             // then send cached remote names
546             for (i=0; i<packet[2];i++){
547                 bt_flip_addr(addr, &packet[3+i*6]);
548                 if (hci_stack.remote_device_db->get_name(&addr, &device_name)){
549                     hci_emit_remote_name_cached(&addr, &device_name);
550                 }
551             }
552             return;
553 #endif
554 
555         case HCI_EVENT_DISCONNECTION_COMPLETE:
556             if (!packet[2]){
557                 handle = READ_BT_16(packet, 3);
558                 hci_connection_t * conn = connection_for_handle(handle);
559                 if (conn) {
560                     hci_shutdown_connection(conn);
561                 }
562             }
563             break;
564 
565         case HCI_EVENT_HARDWARE_ERROR:
566             if(hci_stack.control->hw_error){
567                 (*hci_stack.control->hw_error)();
568             }
569             break;
570 
571         default:
572             break;
573     }
574 
575     // handle BT initialization
576     if (hci_stack.state == HCI_STATE_INITIALIZING){
577         // handle H4 synchronization loss on restart
578         // if (hci_stack.substate == 1 && packet[0] == HCI_EVENT_HARDWARE_ERROR){
579         //    hci_stack.substate = 0;
580         // }
581         // handle normal init sequence
582         if (hci_stack.substate % 2){
583             // odd: waiting for event
584             if (packet[0] == HCI_EVENT_COMMAND_COMPLETE){
585                 hci_stack.substate++;
586             }
587         }
588     }
589 
590     // help with BT sleep
591     if (hci_stack.state == HCI_STATE_FALLING_ASLEEP
592         && hci_stack.substate == 1
593         && COMMAND_COMPLETE_EVENT(packet, hci_write_scan_enable)){
594         hci_stack.substate++;
595     }
596 
597     hci_stack.packet_handler(HCI_EVENT_PACKET, packet, size);
598 
599 	// execute main loop
600 	hci_run();
601 }
602 
603 void packet_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
604     switch (packet_type) {
605         case HCI_EVENT_PACKET:
606             event_handler(packet, size);
607             break;
608         case HCI_ACL_DATA_PACKET:
609             acl_handler(packet, size);
610             break;
611         default:
612             break;
613     }
614 }
615 
616 /** Register HCI packet handlers */
617 void hci_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
618     hci_stack.packet_handler = handler;
619 }
620 
621 void hci_init(hci_transport_t *transport, void *config, bt_control_t *control, remote_device_db_t * remote_device_db){
622 
623     // reference to use transport layer implementation
624     hci_stack.hci_transport = transport;
625 
626     // references to used control implementation
627     hci_stack.control = control;
628 
629     // reference to used config
630     hci_stack.config = config;
631 
632     // no connections yet
633     hci_stack.connections = NULL;
634     hci_stack.discoverable = 0;
635 
636     // higher level handler
637     hci_stack.packet_handler = dummy_handler;
638 
639     // store and open remote device db
640     hci_stack.remote_device_db = remote_device_db;
641     if (hci_stack.remote_device_db) {
642         hci_stack.remote_device_db->open();
643     }
644 
645     // register packet handlers with transport
646     transport->register_packet_handler(&packet_handler);
647 }
648 
649 void hci_close(){
650     // close remote device db
651     if (hci_stack.remote_device_db) {
652         hci_stack.remote_device_db->close();
653     }
654 }
655 
656 // State-Module-Driver overview
657 // state                    module  low-level
658 // HCI_STATE_OFF             off      close
659 // HCI_STATE_INITIALIZING,   on       open
660 // HCI_STATE_WORKING,        on       open
661 // HCI_STATE_HALTING,        on       open
662 // HCI_STATE_SLEEPING,    off/sleep   close
663 // HCI_STATE_FALLING_ASLEEP  on       open
664 
665 static int hci_power_control_on(void){
666 
667     // power on
668     int err = 0;
669     if (hci_stack.control && hci_stack.control->on){
670         err = (*hci_stack.control->on)(hci_stack.config);
671     }
672     if (err){
673         log_error( "POWER_ON failed\n");
674         hci_emit_hci_open_failed();
675         return err;
676     }
677 
678     // open low-level device
679     err = hci_stack.hci_transport->open(hci_stack.config);
680     if (err){
681         log_error( "HCI_INIT failed, turning Bluetooth off again\n");
682         if (hci_stack.control && hci_stack.control->off){
683             (*hci_stack.control->off)(hci_stack.config);
684         }
685         hci_emit_hci_open_failed();
686         return err;
687     }
688     return 0;
689 }
690 
691 static void hci_power_control_off(void){
692 
693     log_info("hci_power_control_off\n");
694 
695     // close low-level device
696     hci_stack.hci_transport->close(hci_stack.config);
697 
698     log_info("hci_power_control_off - hci_transport closed\n");
699 
700     // power off
701     if (hci_stack.control && hci_stack.control->off){
702         (*hci_stack.control->off)(hci_stack.config);
703     }
704 
705     log_info("hci_power_control_off - control closed\n");
706 
707     hci_stack.state = HCI_STATE_OFF;
708 }
709 
710 static void hci_power_control_sleep(void){
711 
712     log_info("hci_power_control_sleep\n");
713 
714 #if 0
715     // don't close serial port during sleep
716 
717     // close low-level device
718     hci_stack.hci_transport->close(hci_stack.config);
719 #endif
720 
721     // sleep mode
722     if (hci_stack.control && hci_stack.control->sleep){
723         (*hci_stack.control->sleep)(hci_stack.config);
724     }
725 
726     hci_stack.state = HCI_STATE_SLEEPING;
727 }
728 
729 static int hci_power_control_wake(void){
730 
731     log_info("hci_power_control_wake\n");
732 
733     // wake on
734     if (hci_stack.control && hci_stack.control->wake){
735         (*hci_stack.control->wake)(hci_stack.config);
736     }
737 
738 #if 0
739     // open low-level device
740     int err = hci_stack.hci_transport->open(hci_stack.config);
741     if (err){
742         log_error( "HCI_INIT failed, turning Bluetooth off again\n");
743         if (hci_stack.control && hci_stack.control->off){
744             (*hci_stack.control->off)(hci_stack.config);
745         }
746         hci_emit_hci_open_failed();
747         return err;
748     }
749 #endif
750 
751     return 0;
752 }
753 
754 
755 int hci_power_control(HCI_POWER_MODE power_mode){
756 
757     log_info("hci_power_control: %u, current mode %u\n", power_mode, hci_stack.state);
758 
759     int err = 0;
760     switch (hci_stack.state){
761 
762         case HCI_STATE_OFF:
763             switch (power_mode){
764                 case HCI_POWER_ON:
765                     err = hci_power_control_on();
766                     if (err) return err;
767                     // set up state machine
768                     hci_stack.num_cmd_packets = 1; // assume that one cmd can be sent
769                     hci_stack.state = HCI_STATE_INITIALIZING;
770                     hci_stack.substate = 0;
771                     break;
772                 case HCI_POWER_OFF:
773                     // do nothing
774                     break;
775                 case HCI_POWER_SLEEP:
776                     // do nothing (with SLEEP == OFF)
777                     break;
778             }
779             break;
780 
781         case HCI_STATE_INITIALIZING:
782             switch (power_mode){
783                 case HCI_POWER_ON:
784                     // do nothing
785                     break;
786                 case HCI_POWER_OFF:
787                     // no connections yet, just turn it off
788                     hci_power_control_off();
789                     break;
790                 case HCI_POWER_SLEEP:
791                     // no connections yet, just turn it off
792                     hci_power_control_sleep();
793                     break;
794             }
795             break;
796 
797         case HCI_STATE_WORKING:
798             switch (power_mode){
799                 case HCI_POWER_ON:
800                     // do nothing
801                     break;
802                 case HCI_POWER_OFF:
803                     // see hci_run
804                     hci_stack.state = HCI_STATE_HALTING;
805                     break;
806                 case HCI_POWER_SLEEP:
807                     // see hci_run
808                     hci_stack.state = HCI_STATE_FALLING_ASLEEP;
809                     hci_stack.substate = 0;
810                     break;
811             }
812             break;
813 
814         case HCI_STATE_HALTING:
815             switch (power_mode){
816                 case HCI_POWER_ON:
817                     // set up state machine
818                     hci_stack.state = HCI_STATE_INITIALIZING;
819                     hci_stack.substate = 0;
820                     break;
821                 case HCI_POWER_OFF:
822                     // do nothing
823                     break;
824                 case HCI_POWER_SLEEP:
825                     // see hci_run
826                     hci_stack.state = HCI_STATE_FALLING_ASLEEP;
827                     hci_stack.substate = 0;
828                     break;
829             }
830             break;
831 
832         case HCI_STATE_FALLING_ASLEEP:
833             switch (power_mode){
834                 case HCI_POWER_ON:
835                     // set up state machine
836                     hci_stack.num_cmd_packets = 1; // assume that one cmd can be sent
837                     hci_stack.state = HCI_STATE_INITIALIZING;
838                     hci_stack.substate = 0;
839                     break;
840                 case HCI_POWER_OFF:
841                     // see hci_run
842                     hci_stack.state = HCI_STATE_HALTING;
843                     break;
844                 case HCI_POWER_SLEEP:
845                     // do nothing
846                     break;
847             }
848             break;
849 
850         case HCI_STATE_SLEEPING:
851             switch (power_mode){
852                 case HCI_POWER_ON:
853                     err = hci_power_control_wake();
854                     if (err) return err;
855                     // set up state machine
856                     hci_stack.num_cmd_packets = 1; // assume that one cmd can be sent
857                     hci_stack.state = HCI_STATE_INITIALIZING;
858                     hci_stack.substate = 0;
859                     break;
860                 case HCI_POWER_OFF:
861                     hci_stack.state = HCI_STATE_HALTING;
862                     break;
863                 case HCI_POWER_SLEEP:
864                     // do nothing
865                     break;
866             }
867             break;
868     }
869 
870     // create internal event
871 	hci_emit_state();
872 
873 	// trigger next/first action
874 	hci_run();
875 
876     return 0;
877 }
878 
879 void hci_discoverable_control(uint8_t enable){
880     if (enable) enable = 1; // normalize argument
881 
882     if (hci_stack.discoverable == enable){
883         hci_emit_discoverable_enabled(hci_stack.discoverable);
884         return;
885     }
886 
887     hci_send_cmd(&hci_write_scan_enable, 2 | enable); // 1 = inq scan, 2 = page scan
888     hci_stack.discoverable = enable;
889 }
890 
891 void hci_run(){
892 
893     hci_connection_t * connection;
894     linked_item_t * it;
895 
896     if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
897 
898     // global/non-connection oriented commands - decline incoming connections
899     if (hci_stack.decline_reason){
900         uint8_t reason = hci_stack.decline_reason;
901         hci_stack.decline_reason = 0;
902         hci_send_cmd(&hci_reject_connection_request, hci_stack.decline_addr, reason);
903     }
904 
905     // send pending HCI commands
906     for (it = (linked_item_t *) hci_stack.connections; it ; it = it->next){
907 
908         connection = (hci_connection_t *) it;
909 
910         if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) {
911             // log_info("hci_run: cannot send command packet\n");
912             return;
913         }
914 
915         if (connection->state == RECEIVED_CONNECTION_REQUEST){
916             log_info("sending hci_accept_connection_request\n");
917             hci_send_cmd(&hci_accept_connection_request, connection->address, 1);
918             connection->state = ACCEPTED_CONNECTION_REQUEST;
919         }
920 
921         if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
922 
923         if (connection->authentication_flags & HANDLE_LINK_KEY_REQUEST){
924             link_key_t link_key;
925             log_info("responding to link key request\n");
926             if ( hci_stack.remote_device_db->get_link_key( &connection->address, &link_key)){
927                hci_send_cmd(&hci_link_key_request_reply, connection->address, &link_key);
928             } else {
929                hci_send_cmd(&hci_link_key_request_negative_reply, connection->address);
930             }
931             connection->authentication_flags &= ~HANDLE_LINK_KEY_REQUEST;
932         }
933     }
934 
935     if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
936 
937     switch (hci_stack.state){
938         case HCI_STATE_INITIALIZING:
939             // log_info("hci_init: substate %u\n", hci_stack.substate);
940             if (hci_stack.substate % 2) {
941                 // odd: waiting for command completion
942                 return;
943             }
944             switch (hci_stack.substate >> 1){
945                 case 0: // RESET
946                     hci_send_cmd(&hci_reset);
947                     if (hci_stack.config == 0 || ((hci_uart_config_t *)hci_stack.config)->baudrate_main == 0){
948                         // skip baud change
949                         hci_stack.substate = 4; // >> 1 = 2
950                     }
951                     break;
952                 case 1: // SEND BAUD CHANGE
953                     hci_stack.control->baudrate_cmd(hci_stack.config, ((hci_uart_config_t *)hci_stack.config)->baudrate_main, hci_stack.hci_packet_buffer);
954                     hci_send_cmd_packet(hci_stack.hci_packet_buffer, 3 + hci_stack.hci_packet_buffer[2]);
955                     break;
956                 case 2: // LOCAL BAUD CHANGE
957                     hci_stack.hci_transport->set_baudrate(((hci_uart_config_t *)hci_stack.config)->baudrate_main);
958                     hci_stack.substate += 2;
959                     // break missing here for fall through
960 
961                 case 3:
962                     // custom initialization
963                     if (hci_stack.control && hci_stack.control->next_cmd){
964                         int valid_cmd = (*hci_stack.control->next_cmd)(hci_stack.config, hci_stack.hci_packet_buffer);
965                         if (valid_cmd){
966                             int size = 3 + hci_stack.hci_packet_buffer[2];
967                             hci_stack.hci_transport->send_packet(HCI_COMMAND_DATA_PACKET, hci_stack.hci_packet_buffer, size);
968                             hci_stack.substate = 4; // more init commands
969                             break;
970                         }
971                         log_info("hci_run: init script done\n\r");
972                     }
973                     // otherwise continue
974 					hci_send_cmd(&hci_read_bd_addr);
975 					break;
976 				case 4:
977 					hci_send_cmd(&hci_read_buffer_size);
978 					break;
979                 case 5:
980                     // ca. 15 sec
981                     hci_send_cmd(&hci_write_page_timeout, 0x6000);
982                     break;
983 				case 6:
984 					hci_send_cmd(&hci_write_scan_enable, 2 | hci_stack.discoverable); // page scan
985 					break;
986                 case 7:
987 #ifndef EMBEDDED
988                 {
989                     char hostname[30];
990                     gethostname(hostname, 30);
991                     hostname[29] = '\0';
992                     hci_send_cmd(&hci_write_local_name, hostname);
993                     break;
994                 }
995                 case 8:
996 #ifdef USE_BLUETOOL
997                     hci_send_cmd(&hci_write_class_of_device, 0x007a020c); // Smartphone
998                     break;
999 
1000                 case 9:
1001 #endif
1002 #endif
1003                     // done.
1004                     hci_stack.state = HCI_STATE_WORKING;
1005                     hci_emit_state();
1006                     break;
1007                 default:
1008                     break;
1009             }
1010             hci_stack.substate++;
1011             break;
1012 
1013         case HCI_STATE_HALTING:
1014 
1015             log_info("HCI_STATE_HALTING\n");
1016             // close all open connections
1017             connection =  (hci_connection_t *) hci_stack.connections;
1018             if (connection){
1019 
1020                 // send disconnect
1021                 if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
1022 
1023                 log_info("HCI_STATE_HALTING, connection %lu, handle %u\n", (uintptr_t) connection, (uint16_t)connection->con_handle);
1024                 hci_send_cmd(&hci_disconnect, connection->con_handle, 0x13);  // remote closed connection
1025 
1026                 // send disconnected event right away - causes higher layer connections to get closed, too.
1027                 hci_shutdown_connection(connection);
1028                 return;
1029             }
1030             log_info("HCI_STATE_HALTING, calling off\n");
1031 
1032             // switch mode
1033             hci_power_control_off();
1034 
1035             log_info("HCI_STATE_HALTING, emitting state\n");
1036             hci_emit_state();
1037             log_info("HCI_STATE_HALTING, done\n");
1038             break;
1039 
1040         case HCI_STATE_FALLING_ASLEEP:
1041             switch(hci_stack.substate) {
1042                 case 0:
1043                     log_info("HCI_STATE_FALLING_ASLEEP\n");
1044                     // close all open connections
1045                     connection =  (hci_connection_t *) hci_stack.connections;
1046                     if (connection){
1047 
1048                         // send disconnect
1049                         if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
1050 
1051                         log_info("HCI_STATE_FALLING_ASLEEP, connection %lu, handle %u\n", (uintptr_t) connection, (uint16_t)connection->con_handle);
1052                         hci_send_cmd(&hci_disconnect, connection->con_handle, 0x13);  // remote closed connection
1053 
1054                         // send disconnected event right away - causes higher layer connections to get closed, too.
1055                         hci_shutdown_connection(connection);
1056                         return;
1057                     }
1058 
1059                     // disable page and inquiry scan
1060                     if (!hci_can_send_packet_now(HCI_COMMAND_DATA_PACKET)) return;
1061 
1062                     log_info("HCI_STATE_HALTING, disabling inq & page scans\n");
1063                     hci_send_cmd(&hci_write_scan_enable, 0); // none
1064 
1065                     // continue in next sub state
1066                     hci_stack.substate++;
1067                     break;
1068                 case 1:
1069                     // wait for command complete "hci_write_scan_enable" in event_handler();
1070                     break;
1071                 case 2:
1072                     log_info("HCI_STATE_HALTING, calling sleep\n");
1073                     // switch mode
1074                     hci_power_control_sleep();  // changes hci_stack.state to SLEEP
1075                     hci_emit_state();
1076                 default:
1077                     break;
1078             }
1079             break;
1080 
1081         default:
1082             break;
1083     }
1084 }
1085 
1086 int hci_send_cmd_packet(uint8_t *packet, int size){
1087     bd_addr_t addr;
1088     hci_connection_t * conn;
1089     // house-keeping
1090 
1091     // create_connection?
1092     if (IS_COMMAND(packet, hci_create_connection)){
1093         bt_flip_addr(addr, &packet[3]);
1094         log_info("Create_connection to %s\n", bd_addr_to_str(addr));
1095         conn = connection_for_address(addr);
1096         if (conn) {
1097             // if connection exists
1098             if (conn->state == OPEN) {
1099                 // and OPEN, emit connection complete command
1100                 hci_emit_connection_complete(conn, 0);
1101             }
1102             //    otherwise, just ignore as it is already in the open process
1103             return 0; // don't sent packet to controller
1104 
1105         }
1106         // create connection struct and register, state = SENT_CREATE_CONNECTION
1107         conn = create_connection_for_addr(addr);
1108         if (!conn){
1109             // notify client that alloc failed
1110             hci_emit_connection_complete(conn, BTSTACK_MEMORY_ALLOC_FAILED);
1111             return 0; // don't sent packet to controller
1112         }
1113         conn->state = SENT_CREATE_CONNECTION;
1114     }
1115 
1116     if (IS_COMMAND(packet, hci_link_key_request_reply)){
1117         hci_add_connection_flags_for_flipped_bd_addr(&packet[3], SENT_LINK_KEY_REPLY);
1118     }
1119     if (IS_COMMAND(packet, hci_link_key_request_negative_reply)){
1120         hci_add_connection_flags_for_flipped_bd_addr(&packet[3], SENT_LINK_KEY_NEGATIVE_REQUEST);
1121     }
1122     if (IS_COMMAND(packet, hci_pin_code_request_reply)){
1123         hci_add_connection_flags_for_flipped_bd_addr(&packet[3], SENT_PIN_CODE_REPLY);
1124     }
1125     if (IS_COMMAND(packet, hci_pin_code_request_negative_reply)){
1126         hci_add_connection_flags_for_flipped_bd_addr(&packet[3], SENT_PIN_CODE_NEGATIVE_REPLY);
1127     }
1128 
1129     if (IS_COMMAND(packet, hci_delete_stored_link_key)){
1130         if (hci_stack.remote_device_db){
1131             bt_flip_addr(addr, &packet[3]);
1132             hci_stack.remote_device_db->delete_link_key(&addr);
1133         }
1134     }
1135 
1136     hci_stack.num_cmd_packets--;
1137     return hci_stack.hci_transport->send_packet(HCI_COMMAND_DATA_PACKET, packet, size);
1138 }
1139 
1140 /**
1141  * pre: numcmds >= 0 - it's allowed to send a command to the controller
1142  */
1143 int hci_send_cmd(const hci_cmd_t *cmd, ...){
1144     va_list argptr;
1145     va_start(argptr, cmd);
1146     uint16_t size = hci_create_cmd_internal(hci_stack.hci_packet_buffer, cmd, argptr);
1147     va_end(argptr);
1148     return hci_send_cmd_packet(hci_stack.hci_packet_buffer, size);
1149 }
1150 
1151 // Create various non-HCI events.
1152 // TODO: generalize, use table similar to hci_create_command
1153 
1154 void hci_emit_state(){
1155     uint8_t event[3];
1156     event[0] = BTSTACK_EVENT_STATE;
1157     event[1] = sizeof(event) - 2;
1158     event[2] = hci_stack.state;
1159     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1160     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1161 }
1162 
1163 void hci_emit_connection_complete(hci_connection_t *conn, uint8_t status){
1164     uint8_t event[13];
1165     event[0] = HCI_EVENT_CONNECTION_COMPLETE;
1166     event[1] = sizeof(event) - 2;
1167     event[2] = status;
1168     bt_store_16(event, 3, conn->con_handle);
1169     bt_flip_addr(&event[5], conn->address);
1170     event[11] = 1; // ACL connection
1171     event[12] = 0; // encryption disabled
1172     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1173     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1174 }
1175 
1176 void hci_emit_disconnection_complete(uint16_t handle, uint8_t reason){
1177     uint8_t event[6];
1178     event[0] = HCI_EVENT_DISCONNECTION_COMPLETE;
1179     event[1] = sizeof(event) - 2;
1180     event[2] = 0; // status = OK
1181     bt_store_16(event, 3, handle);
1182     event[5] = reason;
1183     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1184     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1185 }
1186 
1187 void hci_emit_l2cap_check_timeout(hci_connection_t *conn){
1188     uint8_t event[4];
1189     event[0] = L2CAP_EVENT_TIMEOUT_CHECK;
1190     event[1] = sizeof(event) - 2;
1191     bt_store_16(event, 2, conn->con_handle);
1192     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1193     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1194 }
1195 
1196 void hci_emit_nr_connections_changed(){
1197     uint8_t event[3];
1198     event[0] = BTSTACK_EVENT_NR_CONNECTIONS_CHANGED;
1199     event[1] = sizeof(event) - 2;
1200     event[2] = nr_hci_connections();
1201     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1202     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1203 }
1204 
1205 void hci_emit_hci_open_failed(){
1206     uint8_t event[2];
1207     event[0] = BTSTACK_EVENT_POWERON_FAILED;
1208     event[1] = sizeof(event) - 2;
1209     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1210     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1211 }
1212 
1213 
1214 void hci_emit_btstack_version() {
1215     uint8_t event[6];
1216     event[0] = BTSTACK_EVENT_VERSION;
1217     event[1] = sizeof(event) - 2;
1218     event[2] = BTSTACK_MAJOR;
1219     event[3] = BTSTACK_MINOR;
1220     bt_store_16(event, 4, BTSTACK_REVISION);
1221     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1222     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1223 }
1224 
1225 void hci_emit_system_bluetooth_enabled(uint8_t enabled){
1226     uint8_t event[3];
1227     event[0] = BTSTACK_EVENT_SYSTEM_BLUETOOTH_ENABLED;
1228     event[1] = sizeof(event) - 2;
1229     event[2] = enabled;
1230     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1231     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1232 }
1233 
1234 void hci_emit_remote_name_cached(bd_addr_t *addr, device_name_t *name){
1235     uint8_t event[2+1+6+248];
1236     event[0] = BTSTACK_EVENT_REMOTE_NAME_CACHED;
1237     event[1] = sizeof(event) - 2;
1238     event[2] = 0;   // just to be compatible with HCI_EVENT_REMOTE_NAME_REQUEST_COMPLETE
1239     bt_flip_addr(&event[3], *addr);
1240     memcpy(&event[9], name, 248);
1241     hci_dump_packet(HCI_EVENT_PACKET, 0, event, sizeof(event));
1242     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1243 }
1244 
1245 void hci_emit_discoverable_enabled(uint8_t enabled){
1246     uint8_t event[3];
1247     event[0] = BTSTACK_EVENT_DISCOVERABLE_ENABLED;
1248     event[1] = sizeof(event) - 2;
1249     event[2] = enabled;
1250     hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
1251     hci_stack.packet_handler(HCI_EVENT_PACKET, event, sizeof(event));
1252 }
1253