xref: /btstack/src/classic/hsp_ag.c (revision ddaf35c7579ab4463891f4e60cea40b4398b142c)
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 // *****************************************************************************
39 //
40 // HSP Audio Gateway
41 //
42 // *****************************************************************************
43 
44 #include "btstack_config.h"
45 
46 #include <stdint.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 
51 #include "btstack_debug.h"
52 #include "btstack_event.h"
53 #include "btstack_memory.h"
54 #include "btstack_run_loop.h"
55 #include "classic/core.h"
56 #include "classic/sdp_server.h"
57 #include "classic/sdp_client_rfcomm.h"
58 #include "classic/sdp_util.h"
59 #include "hci.h"
60 #include "hci_cmd.h"
61 #include "hci_dump.h"
62 #include "hsp_ag.h"
63 #include "l2cap.h"
64 
65 #define HSP_HS_BUTTON_PRESS "AT+CKPD=200"
66 #define HSP_HS_AT_CKPD "AT+CKPD\r\n"
67 #define HSP_AG_OK "\r\nOK\r\n"
68 #define HSP_AG_ERROR "\r\nERROR\r\n"
69 #define HSP_AG_RING "\r\nRING\r\n"
70 #define HSP_MICROPHONE_GAIN "+VGM"
71 #define HSP_SPEAKER_GAIN "+VGS"
72 
73 #define HSP_HS_MICROPHONE_GAIN "AT+VGM="
74 #define HSP_HS_SPEAKER_GAIN "AT+VGS="
75 
76 static const char default_hsp_ag_service_name[] = "Audio Gateway";
77 
78 static bd_addr_t remote;
79 static bd_addr_t sco_event_addr;
80 static uint8_t channel_nr = 0;
81 
82 static uint16_t mtu;
83 static uint16_t rfcomm_cid = 0;
84 static uint16_t sco_handle = 0;
85 static uint16_t rfcomm_handle = 0;
86 static btstack_timer_source_t hs_timeout;
87 
88 static int ag_microphone_gain = -1;
89 static int ag_speaker_gain = -1;
90 static uint8_t ag_ring = 0;
91 static uint8_t ag_send_ok = 0;
92 static uint8_t ag_send_error = 0;
93 static uint8_t ag_num_button_press_received = 0;
94 static uint8_t ag_support_custom_commands = 0;
95 static uint8_t ag_establish_sco = 0;
96 static uint8_t hsp_disconnect_rfcomm = 0;
97 static uint8_t hsp_establish_audio_connection = 0;
98 static uint8_t hsp_release_audio_connection = 0;
99 
100 static btstack_packet_callback_registration_t hci_event_callback_registration;
101 
102 typedef enum {
103     HSP_IDLE,
104     HSP_SDP_QUERY_RFCOMM_CHANNEL,
105     HSP_W4_SDP_EVENT_QUERY_COMPLETE,
106     HSP_W4_RFCOMM_CONNECTED,
107 
108     HSP_RFCOMM_CONNECTION_ESTABLISHED,
109 
110     HSP_W4_RING_ANSWER,
111     HSP_W4_USER_ACTION,
112     HSP_W2_CONNECT_SCO,
113     HSP_W4_SCO_CONNECTED,
114 
115     HSP_AUDIO_CONNECTION_ESTABLISHED,
116 
117     HSP_W2_DISCONNECT_SCO,
118     HSP_W4_SCO_DISCONNECTED,
119 
120     HSP_W2_DISCONNECT_RFCOMM,
121     HSP_W4_RFCOMM_DISCONNECTED,
122     HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN
123 } hsp_state_t;
124 
125 static hsp_state_t hsp_state = HSP_IDLE;
126 
127 
128 static btstack_packet_handler_t hsp_ag_callback;
129 
130 static void hsp_run(void);
131 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
132 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
133 
134 static void dummy_notify(uint8_t packet_type, uint16_t channel, uint8_t * event, uint16_t size){}
135 
136 void hsp_ag_register_packet_handler(btstack_packet_handler_t callback){
137     if (callback == NULL){
138         callback = &dummy_notify;
139     }
140     hsp_ag_callback = callback;
141 }
142 
143 static void emit_event(uint8_t event_subtype, uint8_t value){
144     if (!hsp_ag_callback) return;
145     uint8_t event[4];
146     event[0] = HCI_EVENT_HSP_META;
147     event[1] = sizeof(event) - 2;
148     event[2] = event_subtype;
149     event[3] = value; // status 0 == OK
150     (*hsp_ag_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
151 }
152 
153 static void emit_event_audio_connected(uint8_t status, uint16_t handle){
154     if (!hsp_ag_callback) return;
155     uint8_t event[6];
156     event[0] = HCI_EVENT_HSP_META;
157     event[1] = sizeof(event) - 2;
158     event[2] = HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE;
159     event[3] = status;
160     little_endian_store_16(event, 4, handle);
161     (*hsp_ag_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
162 }
163 
164 void hsp_ag_create_sdp_record(uint8_t * service, uint32_t service_record_handle, int rfcomm_channel_nr, const char * name){
165     uint8_t* attribute;
166     de_create_sequence(service);
167 
168     // 0x0000 "Service Record Handle"
169     de_add_number(service, DE_UINT, DE_SIZE_16, SDP_ServiceRecordHandle);
170     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
171 
172     // 0x0001 "Service Class ID List"
173     de_add_number(service,  DE_UINT, DE_SIZE_16, SDP_ServiceClassIDList);
174     attribute = de_push_sequence(service);
175     {
176         //  "UUID for PAN Service"
177         de_add_number(attribute, DE_UUID, DE_SIZE_16, SDP_Headset_AG);
178         de_add_number(attribute, DE_UUID, DE_SIZE_16, SDP_GenericAudio);
179     }
180     de_pop_sequence(service, attribute);
181 
182     // 0x0004 "Protocol Descriptor List"
183     de_add_number(service,  DE_UINT, DE_SIZE_16, SDP_ProtocolDescriptorList);
184     attribute = de_push_sequence(service);
185     {
186         uint8_t* l2cpProtocol = de_push_sequence(attribute);
187         {
188             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, SDP_L2CAPProtocol);
189         }
190         de_pop_sequence(attribute, l2cpProtocol);
191 
192         uint8_t* rfcomm = de_push_sequence(attribute);
193         {
194             de_add_number(rfcomm,  DE_UUID, DE_SIZE_16, SDP_RFCOMMProtocol);  // rfcomm_service
195             de_add_number(rfcomm,  DE_UINT, DE_SIZE_8,  rfcomm_channel_nr);  // rfcomm channel
196         }
197         de_pop_sequence(attribute, rfcomm);
198     }
199     de_pop_sequence(service, attribute);
200 
201     // 0x0005 "Public Browse Group"
202     de_add_number(service,  DE_UINT, DE_SIZE_16, SDP_BrowseGroupList); // public browse group
203     attribute = de_push_sequence(service);
204     {
205         de_add_number(attribute,  DE_UUID, DE_SIZE_16, SDP_PublicBrowseGroup);
206     }
207     de_pop_sequence(service, attribute);
208 
209     // 0x0009 "Bluetooth Profile Descriptor List"
210     de_add_number(service,  DE_UINT, DE_SIZE_16, SDP_BluetoothProfileDescriptorList);
211     attribute = de_push_sequence(service);
212     {
213         uint8_t *sppProfile = de_push_sequence(attribute);
214         {
215             de_add_number(sppProfile,  DE_UUID, DE_SIZE_16, SDP_HSP);
216             de_add_number(sppProfile,  DE_UINT, DE_SIZE_16, 0x0102); // Verision 1.2
217         }
218         de_pop_sequence(attribute, sppProfile);
219     }
220     de_pop_sequence(service, attribute);
221 
222     // 0x0100 "Service Name"
223     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
224     if (name){
225         de_add_data(service,  DE_STRING, strlen(name), (uint8_t *) name);
226     } else {
227         de_add_data(service,  DE_STRING, strlen(default_hsp_ag_service_name), (uint8_t *) default_hsp_ag_service_name);
228     }
229 }
230 
231 static int hsp_ag_send_str_over_rfcomm(const uint16_t cid, char * command){
232     int err = rfcomm_send(cid, (uint8_t*) command, strlen(command));
233     if (err){
234         log_error("rfcomm_send_internal -> error 0X%02x", err);
235         return err;
236     }
237     return err;
238 }
239 
240 void hsp_ag_enable_custom_commands(int enable){
241     ag_support_custom_commands = enable;
242 }
243 
244 int hsp_ag_send_result(char * result){
245     if (!ag_support_custom_commands) return 1;
246     return hsp_ag_send_str_over_rfcomm(rfcomm_cid, result);
247 }
248 
249 static void hsp_ag_reset_state(void){
250     hsp_state = HSP_IDLE;
251 
252     rfcomm_cid = 0;
253     rfcomm_handle = 0;
254     sco_handle = 0;
255 
256     ag_send_ok = 0;
257     ag_send_error = 0;
258     ag_ring = 0;
259 
260     ag_num_button_press_received = 0;
261     ag_support_custom_commands = 0;
262 
263     ag_microphone_gain = -1;
264     ag_speaker_gain = -1;
265 
266     hsp_disconnect_rfcomm = 0;
267     hsp_establish_audio_connection = 0;
268     hsp_release_audio_connection = 0;
269 }
270 
271 void hsp_ag_init(uint8_t rfcomm_channel_nr){
272     // register for HCI events
273     hci_event_callback_registration.callback = &packet_handler;
274     hci_add_event_handler(&hci_event_callback_registration);
275 
276     rfcomm_register_service(packet_handler, rfcomm_channel_nr, 0xffff);  // reserved channel, mtu limited by l2cap
277 
278     hsp_ag_reset_state();
279 }
280 
281 void hsp_ag_connect(bd_addr_t bd_addr){
282     if (hsp_state != HSP_IDLE) return;
283     hsp_state = HSP_SDP_QUERY_RFCOMM_CHANNEL;
284     memcpy(remote, bd_addr, 6);
285     hsp_run();
286 }
287 
288 void hsp_ag_disconnect(void){
289     hsp_ag_release_audio_connection();
290     if (hsp_state < HSP_W4_RFCOMM_CONNECTED){
291         hsp_state = HSP_IDLE;
292         return;
293     }
294 
295     if (hsp_state == HSP_W4_RFCOMM_CONNECTED){
296         hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
297         return;
298     }
299     hsp_disconnect_rfcomm = 1;
300     hsp_run();
301 }
302 
303 void hsp_ag_establish_audio_connection(void){
304     switch (hsp_state){
305         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
306             hsp_establish_audio_connection = 1;
307             hsp_state = HSP_W4_SCO_CONNECTED;
308             break;
309         case HSP_W4_RFCOMM_CONNECTED:
310             hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
311             break;
312         default:
313             break;
314     }
315     hsp_run();
316 }
317 
318 void hsp_ag_release_audio_connection(void){
319     if (hsp_state >= HSP_W2_DISCONNECT_SCO) return;
320     if (hsp_state < HSP_AUDIO_CONNECTION_ESTABLISHED) return;
321 
322     hsp_release_audio_connection = 1;
323     hsp_run();
324 }
325 
326 
327 void hsp_ag_set_microphone_gain(uint8_t gain){
328     if (gain < 0 || gain >15) {
329         log_error("Gain must be in interval [0..15], it is given %d", gain);
330         return;
331     }
332     ag_microphone_gain = gain;
333     hsp_run();
334 }
335 
336 // AG +VGS=5  [0..15] ; HS AT+VGM=6 | AG OK
337 void hsp_ag_set_speaker_gain(uint8_t gain){
338     if (gain < 0 || gain >15) {
339         log_error("Gain must be in interval [0..15], it is given %d", gain);
340         return;
341     }
342     ag_speaker_gain = gain;
343     hsp_run();
344 }
345 
346 static void hsp_ringing_timeout_handler(btstack_timer_source_t * timer){
347     ag_ring = 1;
348     btstack_run_loop_set_timer(&hs_timeout, 2000); // 2 seconds timeout
349     btstack_run_loop_add_timer(&hs_timeout);
350     hsp_run();
351 }
352 
353 static void hsp_ringing_timer_start(void){
354     btstack_run_loop_remove_timer(&hs_timeout);
355     btstack_run_loop_set_timer_handler(&hs_timeout, hsp_ringing_timeout_handler);
356     btstack_run_loop_set_timer(&hs_timeout, 2000); // 2 seconds timeout
357     btstack_run_loop_add_timer(&hs_timeout);
358 }
359 
360 static void hsp_ringing_timer_stop(void){
361     btstack_run_loop_remove_timer(&hs_timeout);
362 }
363 
364 void hsp_ag_start_ringing(void){
365     ag_ring = 1;
366     if (hsp_state == HSP_W2_CONNECT_SCO) {
367         hsp_state = HSP_W4_RING_ANSWER;
368     }
369     hsp_ringing_timer_start();
370 }
371 
372 void hsp_ag_stop_ringing(void){
373     ag_ring = 0;
374     if (hsp_state == HSP_W4_RING_ANSWER){
375         hsp_state = HSP_W2_CONNECT_SCO;
376     }
377     hsp_ringing_timer_stop();
378 }
379 
380 static void hsp_run(void){
381     if (ag_establish_sco && hci_can_send_command_packet_now()){
382         ag_establish_sco = 0;
383 
384         log_info("HSP: sending hci_accept_connection_request.");
385         // remote supported feature eSCO is set if link type is eSCO
386         // eSCO: S4 - max latency == transmission interval = 0x000c == 12 ms,
387         uint16_t max_latency;
388         uint8_t  retransmission_effort;
389         uint16_t packet_types;
390 
391         if (hci_remote_esco_supported(rfcomm_handle)){
392             max_latency = 0x000c;
393             retransmission_effort = 0x02;
394             packet_types = 0x388;
395         } else {
396             max_latency = 0xffff;
397             retransmission_effort = 0xff;
398             packet_types = 0x003f;
399         }
400 
401         uint16_t sco_voice_setting = hci_get_sco_voice_setting();
402 
403         log_info("HFP: sending hci_accept_connection_request, sco_voice_setting %02x", sco_voice_setting);
404         hci_send_cmd(&hci_accept_synchronous_connection, remote, 8000, 8000, max_latency,
405                         sco_voice_setting, retransmission_effort, packet_types);
406         return;
407     }
408 
409     if (ag_send_ok){
410         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
411             rfcomm_request_can_send_now_event(rfcomm_cid);
412             return;
413         }
414         ag_send_ok = 0;
415         hsp_ag_send_str_over_rfcomm(rfcomm_cid, HSP_AG_OK);
416         return;
417     }
418 
419     if (ag_send_error){
420         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
421             rfcomm_request_can_send_now_event(rfcomm_cid);
422             return;
423         }
424         ag_send_error = 0;
425         hsp_ag_send_str_over_rfcomm(rfcomm_cid, HSP_AG_ERROR);
426         return;
427     }
428 
429     if (ag_ring){
430         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
431             rfcomm_request_can_send_now_event(rfcomm_cid);
432             return;
433         }
434         ag_ring = 0;
435         hsp_ag_send_str_over_rfcomm(rfcomm_cid, HSP_AG_RING);
436         return;
437     }
438 
439     if (hsp_establish_audio_connection){
440         if (!hci_can_send_command_packet_now()) return;
441         hsp_establish_audio_connection = 0;
442         hci_send_cmd(&hci_setup_synchronous_connection, rfcomm_handle, 8000, 8000, 0xFFFF, hci_get_sco_voice_setting(), 0xFF, 0x003F);
443         return;
444     }
445 
446     if (hsp_release_audio_connection){
447         hsp_release_audio_connection = 0;
448         gap_disconnect(sco_handle);
449         return;
450     }
451 
452     if (hsp_disconnect_rfcomm){
453         hsp_disconnect_rfcomm = 0;
454         hsp_establish_audio_connection = 0;
455         rfcomm_disconnect(rfcomm_cid);
456         return;
457     }
458 
459     switch (hsp_state){
460         case HSP_SDP_QUERY_RFCOMM_CHANNEL:
461             hsp_state = HSP_W4_SDP_EVENT_QUERY_COMPLETE;
462             log_info("Start SDP query %s, 0x%02x", bd_addr_to_str(remote), SDP_HSP);
463             sdp_client_query_rfcomm_channel_and_name_for_uuid(&handle_query_rfcomm_event, remote, SDP_HSP);
464             break;
465 
466         case HSP_W4_RING_ANSWER:
467             if (!ag_num_button_press_received) break;
468 
469             if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
470                 rfcomm_request_can_send_now_event(rfcomm_cid);
471                 return;
472             }
473 
474             ag_send_ok = 0;
475             ag_num_button_press_received = 0;
476             hsp_state = HSP_W2_CONNECT_SCO;
477 
478             hsp_ag_send_str_over_rfcomm(rfcomm_cid, HSP_AG_OK);
479             break;
480 
481         case HSP_W2_CONNECT_SCO:
482             if (!hci_can_send_command_packet_now()) return;
483             hsp_state = HSP_W4_SCO_CONNECTED;
484             hci_send_cmd(&hci_setup_synchronous_connection, rfcomm_handle, 8000, 8000, 0xFFFF, hci_get_sco_voice_setting(), 0xFF, 0x003F);
485             break;
486 
487         case HSP_W2_DISCONNECT_SCO:
488             ag_num_button_press_received = 0;
489 
490             hsp_state = HSP_W4_SCO_DISCONNECTED;
491             gap_disconnect(sco_handle);
492             break;
493 
494         case HSP_W2_DISCONNECT_RFCOMM:
495             rfcomm_disconnect(rfcomm_cid);
496             break;
497 
498         case HSP_AUDIO_CONNECTION_ESTABLISHED:
499         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
500 
501             if (ag_microphone_gain >= 0){
502                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
503                     rfcomm_request_can_send_now_event(rfcomm_cid);
504                     return;
505                 }
506                 int gain = ag_microphone_gain;
507                 ag_microphone_gain = -1;
508                 char buffer[10];
509                 sprintf(buffer, "%s=%d\r\n", HSP_MICROPHONE_GAIN, gain);
510                 hsp_ag_send_str_over_rfcomm(rfcomm_cid, buffer);
511                 break;
512             }
513 
514             if (ag_speaker_gain >= 0){
515                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
516                     rfcomm_request_can_send_now_event(rfcomm_cid);
517                     return;
518                 }
519                 int gain = ag_speaker_gain;
520                 ag_speaker_gain = -1;
521                 char buffer[10];
522                 sprintf(buffer, "%s=%d\r\n", HSP_SPEAKER_GAIN, gain);
523                 hsp_ag_send_str_over_rfcomm(rfcomm_cid, buffer);
524                 break;
525             }
526             break;
527         default:
528             break;
529     }
530 }
531 
532 
533 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
534     if (packet_type == RFCOMM_DATA_PACKET){
535         while (size > 0 && (packet[0] == '\n' || packet[0] == '\r')){
536             size--;
537             packet++;
538         }
539 
540         if (strncmp((char *)packet, HSP_HS_BUTTON_PRESS, strlen(HSP_HS_BUTTON_PRESS)) == 0){
541             log_info("Received button press %s", HSP_HS_BUTTON_PRESS);
542             ag_send_ok = 1;
543             switch (hsp_state){
544                 case HSP_AUDIO_CONNECTION_ESTABLISHED:
545                     hsp_release_audio_connection = 1;
546                     break;
547                 case HSP_RFCOMM_CONNECTION_ESTABLISHED:
548                     hsp_establish_audio_connection = 1;
549                     break;
550                 default:
551                     break;
552             }
553         } else if (strncmp((char *)packet, HSP_HS_MICROPHONE_GAIN, strlen(HSP_HS_MICROPHONE_GAIN)) == 0){
554             uint8_t gain = (uint8_t)atoi((char*)&packet[strlen(HSP_HS_MICROPHONE_GAIN)]);
555             ag_send_ok = 1;
556             emit_event(HSP_SUBEVENT_MICROPHONE_GAIN_CHANGED, gain);
557 
558         } else if (strncmp((char *)packet, HSP_HS_SPEAKER_GAIN, strlen(HSP_HS_SPEAKER_GAIN)) == 0){
559             uint8_t gain = (uint8_t)atoi((char*)&packet[strlen(HSP_HS_SPEAKER_GAIN)]);
560             ag_send_ok = 1;
561             emit_event(HSP_SUBEVENT_SPEAKER_GAIN_CHANGED, gain);
562 
563         } else if (strncmp((char *)packet, "AT+", 3) == 0){
564             ag_send_error = 1;
565             if (!hsp_ag_callback) return;
566             // re-use incoming buffer to avoid reserving large buffers - ugly but efficient
567             uint8_t * event = packet - 4;
568             event[0] = HCI_EVENT_HSP_META;
569             event[1] = size + 2;
570             event[2] = HSP_SUBEVENT_HS_COMMAND;
571             event[3] = size;
572             (*hsp_ag_callback)(HCI_EVENT_PACKET, 0, event, size+4);
573         }
574 
575         hsp_run();
576         return;
577     }
578 
579     if (packet_type != HCI_EVENT_PACKET) return;
580     uint8_t event = hci_event_packet_get_type(packet);
581     bd_addr_t event_addr;
582     uint16_t handle;
583 
584     switch (event) {
585         case HCI_EVENT_CONNECTION_REQUEST:
586             printf("hsp HCI_EVENT_CONNECTION_REQUEST\n");
587             hci_event_connection_request_get_bd_addr(packet, sco_event_addr);
588             ag_establish_sco = 1;
589             break;
590         case HCI_EVENT_SYNCHRONOUS_CONNECTION_COMPLETE:{
591             uint8_t status = hci_event_synchronous_connection_complete_get_status(packet);
592             if (status != 0){
593                 log_error("(e)SCO Connection failed, status %u", status);
594                 emit_event_audio_connected(status, sco_handle);
595                 break;
596             }
597 
598             hci_event_synchronous_connection_complete_get_bd_addr(packet, event_addr);
599             sco_handle = hci_event_synchronous_connection_complete_get_handle(packet);
600             uint8_t  link_type = hci_event_synchronous_connection_complete_get_link_type(packet);
601             uint8_t  transmission_interval = hci_event_synchronous_connection_complete_get_transmission_interval(packet);  // measured in slots
602             uint8_t  retransmission_interval = hci_event_synchronous_connection_complete_get_retransmission_interval(packet);// measured in slots
603             uint16_t rx_packet_length = hci_event_synchronous_connection_complete_get_rx_packet_length(packet); // measured in bytes
604             uint16_t tx_packet_length = hci_event_synchronous_connection_complete_get_tx_packet_length(packet); // measured in bytes
605             uint8_t  air_mode = hci_event_synchronous_connection_complete_get_air_mode(packet);
606 
607             switch (link_type){
608                 case 0x00:
609                     log_info("SCO Connection established.");
610                     if (transmission_interval != 0) log_error("SCO Connection: transmission_interval not zero: %d.", transmission_interval);
611                     if (retransmission_interval != 0) log_error("SCO Connection: retransmission_interval not zero: %d.", retransmission_interval);
612                     if (rx_packet_length != 0) log_error("SCO Connection: rx_packet_length not zero: %d.", rx_packet_length);
613                     if (tx_packet_length != 0) log_error("SCO Connection: tx_packet_length not zero: %d.", tx_packet_length);
614                     break;
615                 case 0x02:
616                     log_info("eSCO Connection established.");
617                     break;
618                 default:
619                     log_error("(e)SCO reserved link_type 0x%2x", link_type);
620                     break;
621             }
622             log_info("sco_handle 0x%2x, address %s, transmission_interval %u slots, retransmission_interval %u slots, "
623                  " rx_packet_length %u bytes, tx_packet_length %u bytes, air_mode 0x%2x (0x02 == CVSD)", sco_handle,
624                  bd_addr_to_str(event_addr), transmission_interval, retransmission_interval, rx_packet_length, tx_packet_length, air_mode);
625 
626             if (hsp_state == HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN){
627                 hsp_state = HSP_W2_DISCONNECT_SCO;
628                 break;
629             }
630 
631             hsp_state = HSP_AUDIO_CONNECTION_ESTABLISHED;
632             emit_event_audio_connected(status, sco_handle);
633             break;
634         }
635 
636         case RFCOMM_EVENT_INCOMING_CONNECTION:
637             // data: event (8), len(8), address(48), channel (8), rfcomm_cid (16)
638             if (hsp_state != HSP_IDLE) return;
639 
640             rfcomm_event_incoming_connection_get_bd_addr(packet, event_addr);
641             rfcomm_cid = rfcomm_event_incoming_connection_get_server_channel(packet);
642             log_info("RFCOMM channel %u requested for %s", packet[8], bd_addr_to_str(event_addr));
643             hsp_state = HSP_W4_RFCOMM_CONNECTED;
644             rfcomm_accept_connection(rfcomm_cid);
645             break;
646 
647         case RFCOMM_EVENT_CHANNEL_OPENED:
648             log_info("RFCOMM_EVENT_CHANNEL_OPENED packet_handler type %u, packet[0] %x", packet_type, packet[0]);
649             // data: event(8), len(8), status (8), address (48), handle(16), server channel(8), rfcomm_cid(16), max frame size(16)
650             if (rfcomm_event_channel_opened_get_status(packet)) {
651                 log_info("RFCOMM channel open failed, status %u§", rfcomm_event_channel_opened_get_status(packet));
652                 hsp_ag_reset_state();
653                 hsp_state = HSP_IDLE;
654             } else {
655                 // data: event(8) , len(8), status (8), address (48), handle (16), server channel(8), rfcomm_cid(16), max frame size(16)
656                 rfcomm_handle = rfcomm_event_channel_opened_get_con_handle(packet);
657                 rfcomm_cid = rfcomm_event_channel_opened_get_rfcomm_cid(packet);
658                 mtu = rfcomm_event_channel_opened_get_max_frame_size(packet);
659                 log_info("RFCOMM channel open succeeded. New RFCOMM Channel ID %u, max frame size %u, state %d", rfcomm_cid, mtu, hsp_state);
660                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
661             }
662             emit_event(HSP_SUBEVENT_RFCOMM_CONNECTION_COMPLETE, packet[2]);
663             break;
664 
665         case RFCOMM_EVENT_CHANNEL_CLOSED:
666             rfcomm_handle = 0;
667             hsp_state = HSP_IDLE;
668             hsp_ag_reset_state();
669             emit_event(HSP_SUBEVENT_RFCOMM_DISCONNECTION_COMPLETE,0);
670             break;
671 
672         case RFCOMM_EVENT_CAN_SEND_NOW:
673             hsp_run();
674             break;
675 
676         case HCI_EVENT_DISCONNECTION_COMPLETE:
677             handle = little_endian_read_16(packet,3);
678             if (handle == sco_handle){
679                 sco_handle = 0;
680                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
681                 emit_event(HSP_SUBEVENT_AUDIO_DISCONNECTION_COMPLETE,0);
682                 break;
683             }
684             if (handle == rfcomm_handle) {
685                 rfcomm_handle = 0;
686                 hsp_state = HSP_IDLE;
687                 hsp_ag_reset_state();
688                 emit_event(HSP_SUBEVENT_RFCOMM_DISCONNECTION_COMPLETE,0);
689             }
690             break;
691 
692         default:
693             break;
694     }
695 
696     hsp_run();
697 }
698 
699 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
700     switch (packet[0]){
701         case SDP_EVENT_QUERY_RFCOMM_SERVICE:
702             channel_nr = sdp_event_query_rfcomm_service_get_rfcomm_channel(packet);
703             log_info("** Service name: '%s', RFCOMM port %u", sdp_event_query_rfcomm_service_get_name(packet), channel_nr);
704             break;
705         case SDP_EVENT_QUERY_COMPLETE:
706             if (channel_nr > 0){
707                 hsp_state = HSP_W4_RFCOMM_CONNECTED;
708                 log_info("RFCOMM create channel. state %d", HSP_W4_RFCOMM_CONNECTED);
709                 rfcomm_create_channel(packet_handler, remote, channel_nr, NULL);
710                 break;
711             }
712             hsp_ag_reset_state();
713             log_info("Service not found, status %u.\n", sdp_event_query_complete_get_status(packet));
714             if (sdp_event_query_complete_get_status(packet)){
715                 emit_event(HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE, sdp_event_query_complete_get_status(packet));
716             } else {
717                 emit_event(HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE, SDP_SERVICE_NOT_FOUND);
718             }
719             break;
720         default:
721             break;
722     }
723 }
724 
725 
726