xref: /btstack/src/classic/hsp_hs.c (revision c9921182ab4b1f83e3e5c671446dca5ffdf45b90)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define BTSTACK_FILE__ "hsp_hs.c"
39 
40 // *****************************************************************************
41 //
42 // HSP Headset
43 //
44 // *****************************************************************************
45 
46 #include "btstack_config.h"
47 
48 #include <stdint.h>
49 #include <string.h>
50 
51 #include "bluetooth_sdp.h"
52 #include "btstack_debug.h"
53 #include "btstack_event.h"
54 #include "btstack_memory.h"
55 #include "btstack_run_loop.h"
56 #include "classic/core.h"
57 #include "classic/sdp_server.h"
58 #include "classic/sdp_client_rfcomm.h"
59 #include "classic/sdp_util.h"
60 #include "hci.h"
61 #include "hci_cmd.h"
62 #include "hci_dump.h"
63 #include "hsp_hs.h"
64 #include "l2cap.h"
65 
66 #define HSP_AG_OK "OK"
67 #define HSP_AG_ERROR "ERROR"
68 #define HSP_AG_RING "RING"
69 #define HSP_MICROPHONE_GAIN "+VGM="
70 #define HSP_SPEAKER_GAIN "+VGS="
71 
72 #define HSP_HS_AT_CKPD "AT+CKPD=200\r\n"
73 #define HSP_HS_MICROPHONE_GAIN "AT+VGM"
74 #define HSP_HS_SPEAKER_GAIN "AT+VGS"
75 
76 static const char default_hsp_hs_service_name[] = "Headset";
77 
78 static bd_addr_t remote;
79 static uint8_t channel_nr = 0;
80 
81 static uint16_t mtu;
82 static uint16_t rfcomm_cid = 0;
83 static uint16_t sco_handle = 0;
84 static uint16_t rfcomm_handle = HCI_CON_HANDLE_INVALID;
85 
86 // static uint8_t connection_state = 0;
87 
88 static int hs_microphone_gain = -1;
89 static int hs_speaker_gain = -1;
90 
91 static uint8_t hs_send_button_press = 0;
92 static uint8_t wait_ok = 0;
93 static uint8_t hs_accept_sco_connection = 0;
94 
95 static uint8_t hs_support_custom_indications = 0;
96 static btstack_packet_callback_registration_t hci_event_callback_registration;
97 static uint8_t hsp_disconnect_rfcomm = 0;
98 static uint8_t hsp_establish_audio_connection = 0;
99 static uint8_t hsp_release_audio_connection = 0;
100 
101 typedef enum {
102     HSP_IDLE,
103     HSP_SDP_QUERY_RFCOMM_CHANNEL,
104     HSP_W4_SDP_QUERY_COMPLETE,
105     HSP_W4_RFCOMM_CONNECTED,
106 
107     HSP_RFCOMM_CONNECTION_ESTABLISHED,
108 
109     HSP_W2_CONNECT_SCO,
110     HSP_W4_SCO_CONNECTED,
111 
112     HSP_AUDIO_CONNECTION_ESTABLISHED,
113 
114     HSP_W2_DISCONNECT_SCO,
115     HSP_W4_SCO_DISCONNECTED,
116 
117     HSP_W2_DISCONNECT_RFCOMM,
118     HSP_W4_RFCOMM_DISCONNECTED,
119     HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN
120 } hsp_state_t;
121 
122 static hsp_state_t hsp_state = HSP_IDLE;
123 
124 static void hsp_run(void);
125 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
126 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
127 
128 static btstack_packet_handler_t hsp_hs_callback;
129 static void dummy_notify(uint8_t packet_type, uint16_t channel, uint8_t * event, uint16_t size){
130     // ok: no code
131     UNUSED(packet_type);
132     UNUSED(channel);
133     UNUSED(event);
134     UNUSED(size);
135 }
136 
137 void hsp_hs_register_packet_handler(btstack_packet_handler_t callback){
138     if (callback == NULL){
139         callback = &dummy_notify;
140     }
141     hsp_hs_callback = callback;
142 }
143 
144 static void emit_event(uint8_t event_subtype, uint8_t value){
145     if (!hsp_hs_callback) return;
146     uint8_t event[4];
147     event[0] = HCI_EVENT_HSP_META;
148     event[1] = sizeof(event) - 2;
149     event[2] = event_subtype;
150     event[3] = value; // status 0 == OK
151     (*hsp_hs_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
152 }
153 
154 static void emit_ring_event(void){
155     if (!hsp_hs_callback) return;
156     uint8_t event[3];
157     event[0] = HCI_EVENT_HSP_META;
158     event[1] = sizeof(event) - 2;
159     event[2] = HSP_SUBEVENT_RING;
160     (*hsp_hs_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
161 }
162 
163 static void emit_event_audio_connected(uint8_t status, uint16_t handle){
164     if (!hsp_hs_callback) return;
165     uint8_t event[6];
166     event[0] = HCI_EVENT_HSP_META;
167     event[1] = sizeof(event) - 2;
168     event[2] = HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE;
169     event[3] = status;
170     little_endian_store_16(event, 4, handle);
171     (*hsp_hs_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
172 }
173 
174 // remote audio volume control
175 // AG +VGM=13 [0..15] ; HS AT+VGM=6 | AG OK
176 
177 static int hsp_hs_send_str_over_rfcomm(uint16_t cid, const char * command){
178     if (!rfcomm_can_send_packet_now(rfcomm_cid)) return 1;
179     int err = rfcomm_send(cid, (uint8_t*) command, strlen(command));
180     if (err){
181         log_info("rfcomm_send_internal -> error 0X%02x", err);
182     }
183     return err;
184 }
185 
186 void hsp_hs_enable_custom_indications(int enable){
187     hs_support_custom_indications = enable;
188 }
189 
190 int hsp_hs_send_result(const char * result){
191     if (!hs_support_custom_indications) return 1;
192     return hsp_hs_send_str_over_rfcomm(rfcomm_cid, result);
193 }
194 
195 
196 void hsp_hs_create_sdp_record(uint8_t * service,  uint32_t service_record_handle, int rfcomm_channel_nr, const char * name, uint8_t have_remote_audio_control){
197     uint8_t* attribute;
198     de_create_sequence(service);
199 
200     // 0x0000 "Service Record Handle"
201     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
202     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
203 
204     // 0x0001 "Service Class ID List"
205     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
206     attribute = de_push_sequence(service);
207     {
208         //  see Bluetooth Erratum #3507
209         de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_HEADSET);       // 0x1108
210         de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_HEADSET_HS);    // 0x1131
211         de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_GENERIC_AUDIO); // 0x1203
212     }
213     de_pop_sequence(service, attribute);
214 
215     // 0x0004 "Protocol Descriptor List"
216     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
217     attribute = de_push_sequence(service);
218     {
219         uint8_t* l2cpProtocol = de_push_sequence(attribute);
220         {
221             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
222         }
223         de_pop_sequence(attribute, l2cpProtocol);
224 
225         uint8_t* rfcomm = de_push_sequence(attribute);
226         {
227             de_add_number(rfcomm,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_RFCOMM);  // rfcomm_service
228             de_add_number(rfcomm,  DE_UINT, DE_SIZE_8,  rfcomm_channel_nr);  // rfcomm channel
229         }
230         de_pop_sequence(attribute, rfcomm);
231     }
232     de_pop_sequence(service, attribute);
233 
234     // 0x0005 "Public Browse Group"
235     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
236     attribute = de_push_sequence(service);
237     {
238         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
239     }
240     de_pop_sequence(service, attribute);
241 
242     // 0x0009 "Bluetooth Profile Descriptor List"
243     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
244     attribute = de_push_sequence(service);
245     {
246         uint8_t *hsp_profile = de_push_sequence(attribute);
247         {
248             de_add_number(hsp_profile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_HEADSET);
249             de_add_number(hsp_profile,  DE_UINT, DE_SIZE_16, 0x0102); // Verision 1.2
250         }
251         de_pop_sequence(attribute, hsp_profile);
252     }
253     de_pop_sequence(service, attribute);
254 
255     // 0x0100 "Service Name"
256     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
257     if (name){
258         de_add_data(service,  DE_STRING, strlen(name), (uint8_t *) name);
259     } else {
260         de_add_data(service,  DE_STRING, strlen(default_hsp_hs_service_name), (uint8_t *) default_hsp_hs_service_name);
261     }
262 
263     // Remote audio volume control
264     de_add_number(service, DE_UINT, DE_SIZE_16, 0x030C);
265     de_add_number(service, DE_BOOL, DE_SIZE_8, have_remote_audio_control);
266 }
267 
268 static void hsp_hs_reset_state(void){
269     hsp_state = HSP_IDLE;
270     hs_microphone_gain = -1;
271     hs_speaker_gain = -1;
272 
273     hs_send_button_press = 0;
274     wait_ok = 0;
275     hs_support_custom_indications = 0;
276 
277     hsp_disconnect_rfcomm = 0;
278     hsp_establish_audio_connection = 0;
279     hsp_release_audio_connection = 0;
280 }
281 
282 void hsp_hs_init(uint8_t rfcomm_channel_nr){
283     // register for HCI events
284     hci_event_callback_registration.callback = &packet_handler;
285     hci_add_event_handler(&hci_event_callback_registration);
286 
287     rfcomm_register_service(packet_handler, rfcomm_channel_nr, 0xffff);  // reserved channel, mtu limited by l2cap
288 
289     hsp_hs_reset_state();
290 }
291 
292 
293 void hsp_hs_connect(bd_addr_t bd_addr){
294     if (hsp_state != HSP_IDLE) return;
295     hsp_state = HSP_SDP_QUERY_RFCOMM_CHANNEL;
296     (void)memcpy(remote, bd_addr, 6);
297     hsp_run();
298 }
299 
300 void hsp_hs_disconnect(void){
301     hsp_hs_release_audio_connection();
302 
303     if (hsp_state < HSP_W4_RFCOMM_CONNECTED){
304         hsp_state = HSP_IDLE;
305         return;
306     }
307 
308     if (hsp_state == HSP_W4_RFCOMM_CONNECTED){
309         hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
310         return;
311     }
312 
313     hsp_establish_audio_connection = 0;
314     rfcomm_disconnect(rfcomm_cid);
315 }
316 
317 
318 void hsp_hs_establish_audio_connection(void){
319     switch (hsp_state){
320         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
321             hsp_establish_audio_connection = 1;
322             hsp_state = HSP_W4_SCO_CONNECTED;
323             break;
324         case HSP_W4_RFCOMM_CONNECTED:
325             hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
326             break;
327         default:
328             break;
329     }
330     hsp_run();
331 }
332 
333 void hsp_hs_release_audio_connection(void){
334     if (hsp_state >= HSP_W2_DISCONNECT_SCO) return;
335     if (hsp_state < HSP_AUDIO_CONNECTION_ESTABLISHED) return;
336     hsp_release_audio_connection = 1;
337     hsp_run();
338 }
339 
340 void hsp_hs_set_microphone_gain(uint8_t gain){
341     if (gain >15) {
342         log_info("Gain must be in interval [0..15], it is given %d", gain);
343         return;
344     }
345     hs_microphone_gain = gain;
346     hsp_run();
347 }
348 
349 // AG +VGS=5  [0..15] ; HS AT+VGM=6 | AG OK
350 void hsp_hs_set_speaker_gain(uint8_t gain){
351     if (gain >15) {
352         log_info("Gain must be in interval [0..15], it is given %d", gain);
353         return;
354     }
355     hs_speaker_gain = gain;
356     hsp_run();
357 }
358 
359 static void hsp_run_handle_state(void){
360     switch (hsp_state){
361         case HSP_SDP_QUERY_RFCOMM_CHANNEL:
362             hsp_state = HSP_W4_SDP_QUERY_COMPLETE;
363             sdp_client_query_rfcomm_channel_and_name_for_uuid(&handle_query_rfcomm_event, remote, BLUETOOTH_SERVICE_CLASS_HEADSET_AUDIO_GATEWAY_AG);
364             break;
365 
366         case HSP_AUDIO_CONNECTION_ESTABLISHED:
367         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
368 
369             if (hs_microphone_gain >= 0){
370                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
371                     rfcomm_request_can_send_now_event(rfcomm_cid);
372                     return;
373                 }
374                 char buffer[20];
375                 sprintf(buffer, "%s=%d\r\n", HSP_HS_MICROPHONE_GAIN, hs_microphone_gain);
376                 hsp_hs_send_str_over_rfcomm(rfcomm_cid, buffer);
377                 hs_microphone_gain = -1;
378                 break;
379             }
380 
381             if (hs_speaker_gain >= 0){
382                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
383                     rfcomm_request_can_send_now_event(rfcomm_cid);
384                     return;
385                 }
386                 char buffer[20];
387                 sprintf(buffer, "%s=%d\r\n", HSP_HS_SPEAKER_GAIN, hs_speaker_gain);
388                 hsp_hs_send_str_over_rfcomm(rfcomm_cid, buffer);
389                 hs_speaker_gain = -1;
390                 break;
391             }
392             break;
393         case HSP_W4_RFCOMM_DISCONNECTED:
394             rfcomm_disconnect(rfcomm_cid);
395             break;
396         default:
397             break;
398     }
399 }
400 
401 static void hsp_run(void){
402 
403     if (wait_ok) return;
404 
405     if (hs_accept_sco_connection && hci_can_send_command_packet_now()){
406 
407         bool eSCO = hs_accept_sco_connection == 2;
408         hs_accept_sco_connection = 0;
409 
410         log_info("HSP: sending hci_accept_connection_request.");
411         // remote supported feature eSCO is set if link type is eSCO
412         // eSCO: S4 - max latency == transmission interval = 0x000c == 12 ms,
413         uint16_t max_latency;
414         uint8_t  retransmission_effort;
415         uint16_t packet_types;
416 
417         if (eSCO && hci_extended_sco_link_supported() && hci_remote_esco_supported(rfcomm_handle)){
418             max_latency = 0x000c;
419             retransmission_effort = 0x02;
420             packet_types = 0x388;
421         } else {
422             max_latency = 0xffff;
423             retransmission_effort = 0xff;
424             packet_types = 0x003f;
425         }
426 
427         uint16_t sco_voice_setting = hci_get_sco_voice_setting();
428 
429         log_info("HFP: sending hci_accept_connection_request, sco_voice_setting %02x", sco_voice_setting);
430         hci_send_cmd(&hci_accept_synchronous_connection, remote, 8000, 8000, max_latency,
431                         sco_voice_setting, retransmission_effort, packet_types);
432         return;
433     }
434 
435     if (hsp_release_audio_connection){
436         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
437             rfcomm_request_can_send_now_event(rfcomm_cid);
438             return;
439         }
440         hsp_release_audio_connection = 0;
441         wait_ok = 1;
442         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
443         return;
444     }
445 
446     if (hsp_establish_audio_connection){
447         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
448             rfcomm_request_can_send_now_event(rfcomm_cid);
449             return;
450         }
451         hsp_establish_audio_connection = 0;
452         wait_ok = 1;
453         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
454         return;
455     }
456 
457     if (hs_send_button_press){
458         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
459             rfcomm_request_can_send_now_event(rfcomm_cid);
460             return;
461         }
462         hs_send_button_press = 0;
463         wait_ok = 1;
464         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
465         return;
466     }
467 
468     hsp_run_handle_state();
469 }
470 
471 
472 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
473     UNUSED(channel);    // ok: no channel for HCI_EVENT_PACKET and only single active RFCOMM channel
474     if (packet_type == RFCOMM_DATA_PACKET){
475         // skip over leading newline
476         while ((size > 0) && ((packet[0] == '\n') || (packet[0] == '\r'))){
477             size--;
478             packet++;
479         }
480         if (strncmp((char *)packet, HSP_AG_RING, strlen(HSP_AG_RING)) == 0){
481             emit_ring_event();
482         } else if (strncmp((char *)packet, HSP_AG_OK, strlen(HSP_AG_OK)) == 0){
483            wait_ok = 0;
484         } else if (strncmp((char *)packet, HSP_MICROPHONE_GAIN, strlen(HSP_MICROPHONE_GAIN)) == 0){
485             uint8_t gain = (uint8_t)btstack_atoi((char*)&packet[strlen(HSP_MICROPHONE_GAIN)]);
486             emit_event(HSP_SUBEVENT_MICROPHONE_GAIN_CHANGED, gain);
487 
488         } else if (strncmp((char *)packet, HSP_SPEAKER_GAIN, strlen(HSP_SPEAKER_GAIN)) == 0){
489             uint8_t gain = (uint8_t)btstack_atoi((char*)&packet[strlen(HSP_SPEAKER_GAIN)]);
490             emit_event(HSP_SUBEVENT_SPEAKER_GAIN_CHANGED, gain);
491         } else {
492             if (!hsp_hs_callback) return;
493             // strip trailing newline
494             while ((size > 0) && ((packet[size-1] == '\n') || (packet[size-1] == '\r'))){
495                 size--;
496             }
497             // add trailing \0
498             packet[size] = 0;
499             // re-use incoming buffer to avoid reserving large buffers - ugly but efficient
500             uint8_t * event = packet - 4;
501             event[0] = HCI_EVENT_HSP_META;
502             event[1] = size + 2;
503             event[2] = HSP_SUBEVENT_AG_INDICATION;
504             event[3] = size;
505             (*hsp_hs_callback)(HCI_EVENT_PACKET, 0, event, size+4);
506         }
507         hsp_run();
508         return;
509     }
510 
511     if (packet_type != HCI_EVENT_PACKET) return;
512 
513     uint8_t event = hci_event_packet_get_type(packet);
514     bd_addr_t event_addr;
515     uint16_t handle;
516     switch (event) {
517         case HCI_EVENT_CONNECTION_REQUEST:
518             switch(hci_event_connection_request_get_link_type(packet)){
519                 case 0: //  SCO
520                 case 2: // eSCO
521                     hci_event_connection_request_get_bd_addr(packet, event_addr);
522                     if (bd_addr_cmp(event_addr, remote) == 0){
523                         if (hci_event_connection_request_get_link_type(packet) == 2){
524                             hs_accept_sco_connection = 2;
525                         } else {
526                             hs_accept_sco_connection = 1;
527                         }
528                         log_info("hs_accept_sco_connection %u", hs_accept_sco_connection);
529                     }
530                     break;
531                 default:
532                     break;
533             }
534             break;
535 
536         case HCI_EVENT_SYNCHRONOUS_CONNECTION_COMPLETE:{
537             if (hsp_state < HSP_RFCOMM_CONNECTION_ESTABLISHED) return;
538             hci_event_synchronous_connection_complete_get_bd_addr(packet, event_addr);
539             uint8_t status                   = hci_event_synchronous_connection_complete_get_status(packet);
540             sco_handle                       = hci_event_synchronous_connection_complete_get_handle(packet);
541             uint8_t  link_type               = hci_event_synchronous_connection_complete_get_link_type(packet);
542             uint8_t  transmission_interval   = hci_event_synchronous_connection_complete_get_transmission_interval(packet);   // measured in slots
543             uint8_t  retransmission_interval = hci_event_synchronous_connection_complete_get_retransmission_interval(packet); // measured in slots
544             uint16_t rx_packet_length        = hci_event_synchronous_connection_complete_get_rx_packet_length(packet);        // measured in bytes
545             uint16_t tx_packet_length        = hci_event_synchronous_connection_complete_get_tx_packet_length(packet);        // measured in bytes
546             uint8_t  air_mode                = hci_event_synchronous_connection_complete_get_air_mode(packet);
547 
548             if (status != 0){
549                 log_error("(e)SCO Connection failed, status %u", status);
550                 emit_event_audio_connected(status, sco_handle);
551                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED ;
552                 break;
553             }
554 
555             switch (link_type){
556                 case 0x00:
557                     log_info("SCO Connection established.");
558                     if (transmission_interval != 0) log_error("SCO Connection: transmission_interval not zero: %d.", transmission_interval);
559                     if (retransmission_interval != 0) log_error("SCO Connection: retransmission_interval not zero: %d.", retransmission_interval);
560                     if (rx_packet_length != 0) log_error("SCO Connection: rx_packet_length not zero: %d.", rx_packet_length);
561                     if (tx_packet_length != 0) log_error("SCO Connection: tx_packet_length not zero: %d.", tx_packet_length);
562                     break;
563                 case 0x02:
564                     log_info("eSCO Connection established.");
565                     break;
566                 default:
567                     log_error("(e)SCO reserved link_type 0x%2x", link_type);
568                     break;
569             }
570             log_info("sco_handle 0x%2x, address %s, transmission_interval %u slots, retransmission_interval %u slots, "
571                  " rx_packet_length %u bytes, tx_packet_length %u bytes, air_mode 0x%2x (0x02 == CVSD)", sco_handle,
572                  bd_addr_to_str(event_addr), transmission_interval, retransmission_interval, rx_packet_length, tx_packet_length, air_mode);
573 
574             hsp_state = HSP_AUDIO_CONNECTION_ESTABLISHED;
575             emit_event_audio_connected(status, sco_handle);
576             break;
577         }
578 
579         case RFCOMM_EVENT_INCOMING_CONNECTION:
580             if (hsp_state != HSP_IDLE) return;
581             rfcomm_event_incoming_connection_get_bd_addr(packet, event_addr);
582             rfcomm_cid = rfcomm_event_incoming_connection_get_rfcomm_cid(packet);
583             log_info("RFCOMM channel %u requested for %s", rfcomm_event_incoming_connection_get_server_channel(packet), bd_addr_to_str(event_addr));
584             hsp_state = HSP_W4_RFCOMM_CONNECTED;
585             rfcomm_accept_connection(rfcomm_cid);
586             break;
587 
588         case RFCOMM_EVENT_CHANNEL_OPENED:
589             if (hsp_state != HSP_W4_RFCOMM_CONNECTED) return;
590             if (rfcomm_event_channel_opened_get_status(packet)) {
591                 log_info("RFCOMM channel open failed, status %u", rfcomm_event_channel_opened_get_status(packet));
592                 hsp_state = HSP_IDLE;
593                 hsp_hs_reset_state();
594             } else {
595                 rfcomm_event_channel_opened_get_bd_addr(packet, remote);
596                 rfcomm_handle = rfcomm_event_channel_opened_get_con_handle(packet);
597                 rfcomm_cid    = rfcomm_event_channel_opened_get_rfcomm_cid(packet);
598                 mtu           = rfcomm_event_channel_opened_get_max_frame_size(packet);
599                 log_info("RFCOMM channel open succeeded. New RFCOMM Channel ID %u, max frame size %u, handle %02x", rfcomm_cid, mtu, rfcomm_handle);
600                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
601             }
602             emit_event(HSP_SUBEVENT_RFCOMM_CONNECTION_COMPLETE, rfcomm_event_channel_opened_get_status(packet));
603             break;
604 
605         case RFCOMM_EVENT_CAN_SEND_NOW:
606             hsp_run();
607             break;
608 
609         case HCI_EVENT_DISCONNECTION_COMPLETE:
610             handle = hci_event_disconnection_complete_get_connection_handle(packet);
611             if (handle == sco_handle){
612                 sco_handle = 0;
613                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
614                 emit_event(HSP_SUBEVENT_AUDIO_DISCONNECTION_COMPLETE,0);
615                 break;
616             }
617             break;
618 
619         case RFCOMM_EVENT_CHANNEL_CLOSED:
620             hsp_state = HSP_IDLE;
621             hsp_hs_reset_state();
622             emit_event(HSP_SUBEVENT_RFCOMM_DISCONNECTION_COMPLETE,0);
623             break;
624 
625         default:
626             break;
627     }
628 
629     hsp_run();
630 }
631 
632 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
633     UNUSED(packet_type);    // ok: handling own sdp events
634     UNUSED(channel);        // ok: no channel
635     UNUSED(size);           // ok: handling own sdp events
636 
637     switch (hci_event_packet_get_type(packet)){
638         case SDP_EVENT_QUERY_RFCOMM_SERVICE:
639             channel_nr = sdp_event_query_rfcomm_service_get_rfcomm_channel(packet);
640             log_info("** Service name: '%s', RFCOMM port %u", sdp_event_query_rfcomm_service_get_name(packet), channel_nr);
641             break;
642         case SDP_EVENT_QUERY_COMPLETE:
643             if (channel_nr > 0){
644                 hsp_state = HSP_W4_RFCOMM_CONNECTED;
645                 log_info("HSP: SDP_QUERY_COMPLETE. RFCOMM create channel, addr %s, rfcomm channel nr %d", bd_addr_to_str(remote), channel_nr);
646                 rfcomm_create_channel(packet_handler, remote, channel_nr, NULL);
647                 break;
648             }
649             hsp_hs_reset_state();
650             log_info("Service not found, status %u.", sdp_event_query_complete_get_status(packet));
651             if (sdp_event_query_complete_get_status(packet)){
652                 emit_event(HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE, sdp_event_query_complete_get_status(packet));
653             } else {
654                 emit_event(HSP_SUBEVENT_AUDIO_CONNECTION_COMPLETE, SDP_SERVICE_NOT_FOUND);
655             }
656             break;
657     }
658 }
659 
660 void hsp_hs_send_button_press(void){
661     if ((hsp_state < HSP_RFCOMM_CONNECTION_ESTABLISHED) || (hsp_state >= HSP_W4_RFCOMM_DISCONNECTED)) return;
662     hs_send_button_press = 1;
663     hsp_run();
664 }
665