xref: /btstack/src/classic/hsp_hs.c (revision d40c3de009bce6994e726da5a427e08951b353d9)
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 <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 
53 #include "bluetooth_sdp.h"
54 #include "btstack_debug.h"
55 #include "btstack_event.h"
56 #include "btstack_memory.h"
57 #include "btstack_run_loop.h"
58 #include "classic/core.h"
59 #include "classic/sdp_server.h"
60 #include "classic/sdp_client_rfcomm.h"
61 #include "classic/sdp_util.h"
62 #include "hci.h"
63 #include "hci_cmd.h"
64 #include "hci_dump.h"
65 #include "hsp_hs.h"
66 #include "l2cap.h"
67 
68 #define HSP_AG_OK "OK"
69 #define HSP_AG_ERROR "ERROR"
70 #define HSP_AG_RING "RING"
71 #define HSP_MICROPHONE_GAIN "+VGM="
72 #define HSP_SPEAKER_GAIN "+VGS="
73 
74 #define HSP_HS_AT_CKPD "AT+CKPD=200\r\n"
75 #define HSP_HS_MICROPHONE_GAIN "AT+VGM"
76 #define HSP_HS_SPEAKER_GAIN "AT+VGS"
77 
78 static const char default_hsp_hs_service_name[] = "Headset";
79 
80 static bd_addr_t remote = {0x04, 0x0C, 0xCE, 0xE4, 0x85, 0xD3};
81 static uint8_t channel_nr = 0;
82 
83 static uint16_t mtu;
84 static uint16_t rfcomm_cid = 0;
85 static uint16_t sco_handle = 0;
86 static uint16_t rfcomm_handle = 0;
87 
88 // static uint8_t connection_state = 0;
89 
90 static int hs_microphone_gain = -1;
91 static int hs_speaker_gain = -1;
92 
93 static uint8_t hs_send_button_press = 0;
94 static uint8_t wait_ok = 0;
95 
96 static uint8_t hs_support_custom_indications = 0;
97 static btstack_packet_callback_registration_t hci_event_callback_registration;
98 static uint8_t hsp_disconnect_rfcomm = 0;
99 static uint8_t hsp_establish_audio_connection = 0;
100 static uint8_t hsp_release_audio_connection = 0;
101 
102 typedef enum {
103     HSP_IDLE,
104     HSP_SDP_QUERY_RFCOMM_CHANNEL,
105     HSP_W4_SDP_QUERY_COMPLETE,
106     HSP_W4_RFCOMM_CONNECTED,
107 
108     HSP_RFCOMM_CONNECTION_ESTABLISHED,
109 
110     HSP_W2_CONNECT_SCO,
111     HSP_W4_SCO_CONNECTED,
112 
113     HSP_AUDIO_CONNECTION_ESTABLISHED,
114 
115     HSP_W2_DISCONNECT_SCO,
116     HSP_W4_SCO_DISCONNECTED,
117 
118     HSP_W2_DISCONNECT_RFCOMM,
119     HSP_W4_RFCOMM_DISCONNECTED,
120     HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN
121 } hsp_state_t;
122 
123 static hsp_state_t hsp_state = HSP_IDLE;
124 
125 static void hsp_run(void);
126 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
127 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
128 
129 static btstack_packet_handler_t hsp_hs_callback;
130 static void dummy_notify(uint8_t packet_type, uint16_t channel, uint8_t * event, uint16_t size){
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_init();
288     rfcomm_register_service(packet_handler, rfcomm_channel_nr, 0xffff);  // reserved channel, mtu limited by l2cap
289 
290     hsp_hs_reset_state();
291 }
292 
293 
294 void hsp_hs_connect(bd_addr_t bd_addr){
295     if (hsp_state != HSP_IDLE) return;
296     hsp_state = HSP_SDP_QUERY_RFCOMM_CHANNEL;
297     memcpy(remote, bd_addr, 6);
298     hsp_run();
299 }
300 
301 void hsp_hs_disconnect(void){
302     hsp_hs_release_audio_connection();
303 
304     if (hsp_state < HSP_W4_RFCOMM_CONNECTED){
305         hsp_state = HSP_IDLE;
306         return;
307     }
308 
309     if (hsp_state == HSP_W4_RFCOMM_CONNECTED){
310         hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
311         return;
312     }
313 
314     if (hsp_state < HSP_W4_SCO_CONNECTED){
315         hsp_state = HSP_W2_DISCONNECT_RFCOMM;
316         return;
317     }
318 
319     hsp_disconnect_rfcomm = 1;
320     hsp_run();
321 }
322 
323 
324 void hsp_hs_establish_audio_connection(void){
325     switch (hsp_state){
326         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
327             hsp_establish_audio_connection = 1;
328             hsp_state = HSP_W4_SCO_CONNECTED;
329             break;
330         case HSP_W4_RFCOMM_CONNECTED:
331             hsp_state = HSP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
332             break;
333         default:
334             break;
335     }
336     hsp_run();
337 }
338 
339 void hsp_hs_release_audio_connection(void){
340     if (hsp_state >= HSP_W2_DISCONNECT_SCO) return;
341     if (hsp_state < HSP_AUDIO_CONNECTION_ESTABLISHED) return;
342     hsp_release_audio_connection = 1;
343     hsp_run();
344 }
345 
346 void hsp_hs_set_microphone_gain(uint8_t gain){
347     if (gain >15) {
348         log_info("Gain must be in interval [0..15], it is given %d", gain);
349         return;
350     }
351     hs_microphone_gain = gain;
352     hsp_run();
353 }
354 
355 // AG +VGS=5  [0..15] ; HS AT+VGM=6 | AG OK
356 void hsp_hs_set_speaker_gain(uint8_t gain){
357     if (gain >15) {
358         log_info("Gain must be in interval [0..15], it is given %d", gain);
359         return;
360     }
361     hs_speaker_gain = gain;
362     hsp_run();
363 }
364 
365 
366 static void hsp_run(void){
367 
368     if (wait_ok) return;
369 
370     if (hsp_release_audio_connection){
371         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
372             rfcomm_request_can_send_now_event(rfcomm_cid);
373             return;
374         }
375         hsp_release_audio_connection = 0;
376         wait_ok = 1;
377         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
378         return;
379     }
380 
381     if (hsp_disconnect_rfcomm){
382         hsp_disconnect_rfcomm = 0;
383         hsp_establish_audio_connection = 0;
384         rfcomm_disconnect(rfcomm_cid);
385         return;
386     }
387 
388     if (hsp_establish_audio_connection){
389         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
390             rfcomm_request_can_send_now_event(rfcomm_cid);
391             return;
392         }
393         hsp_establish_audio_connection = 0;
394         wait_ok = 1;
395         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
396         return;
397     }
398 
399     if (hs_send_button_press){
400         if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
401             rfcomm_request_can_send_now_event(rfcomm_cid);
402             return;
403         }
404         hs_send_button_press = 0;
405         wait_ok = 1;
406         hsp_hs_send_str_over_rfcomm(rfcomm_cid, HSP_HS_AT_CKPD);
407         return;
408     }
409 
410     switch (hsp_state){
411         case HSP_SDP_QUERY_RFCOMM_CHANNEL:
412             hsp_state = HSP_W4_SDP_QUERY_COMPLETE;
413             sdp_client_query_rfcomm_channel_and_name_for_uuid(&handle_query_rfcomm_event, remote, BLUETOOTH_SERVICE_CLASS_HEADSET_AUDIO_GATEWAY_AG);
414             break;
415 
416         case HSP_AUDIO_CONNECTION_ESTABLISHED:
417         case HSP_RFCOMM_CONNECTION_ESTABLISHED:
418 
419             if (hs_microphone_gain >= 0){
420                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
421                     rfcomm_request_can_send_now_event(rfcomm_cid);
422                     return;
423                 }
424                 char buffer[20];
425                 sprintf(buffer, "%s=%d\r\n", HSP_HS_MICROPHONE_GAIN, hs_microphone_gain);
426                 hsp_hs_send_str_over_rfcomm(rfcomm_cid, buffer);
427                 hs_microphone_gain = -1;
428                 break;
429             }
430 
431             if (hs_speaker_gain >= 0){
432                 if (!rfcomm_can_send_packet_now(rfcomm_cid)) {
433                     rfcomm_request_can_send_now_event(rfcomm_cid);
434                     return;
435                 }
436                 char buffer[20];
437                 sprintf(buffer, "%s=%d\r\n", HSP_HS_SPEAKER_GAIN, hs_speaker_gain);
438                 hsp_hs_send_str_over_rfcomm(rfcomm_cid, buffer);
439                 hs_speaker_gain = -1;
440                 break;
441             }
442             break;
443         case HSP_W4_RFCOMM_DISCONNECTED:
444             rfcomm_disconnect(rfcomm_cid);
445             break;
446         default:
447             break;
448     }
449 }
450 
451 
452 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
453     UNUSED(channel);
454 
455     // printf("packet_handler type %u, packet[0] %x\n", packet_type, packet[0]);
456     if (packet_type == RFCOMM_DATA_PACKET){
457         // skip over leading newline
458         while (size > 0 && (packet[0] == '\n' || packet[0] == '\r')){
459             size--;
460             packet++;
461         }
462         if (strncmp((char *)packet, HSP_AG_RING, strlen(HSP_AG_RING)) == 0){
463             emit_ring_event();
464         } else if (strncmp((char *)packet, HSP_AG_OK, strlen(HSP_AG_OK)) == 0){
465            wait_ok = 0;
466         } else if (strncmp((char *)packet, HSP_MICROPHONE_GAIN, strlen(HSP_MICROPHONE_GAIN)) == 0){
467             uint8_t gain = (uint8_t)btstack_atoi((char*)&packet[strlen(HSP_MICROPHONE_GAIN)]);
468             emit_event(HSP_SUBEVENT_MICROPHONE_GAIN_CHANGED, gain);
469 
470         } else if (strncmp((char *)packet, HSP_SPEAKER_GAIN, strlen(HSP_SPEAKER_GAIN)) == 0){
471             uint8_t gain = (uint8_t)btstack_atoi((char*)&packet[strlen(HSP_SPEAKER_GAIN)]);
472             emit_event(HSP_SUBEVENT_SPEAKER_GAIN_CHANGED, gain);
473         } else {
474             if (!hsp_hs_callback) return;
475             // strip trailing newline
476             while (size > 0 && (packet[size-1] == '\n' || packet[size-1] == '\r')){
477                 size--;
478             }
479             // add trailing \0
480             packet[size] = 0;
481             // re-use incoming buffer to avoid reserving large buffers - ugly but efficient
482             uint8_t * event = packet - 4;
483             event[0] = HCI_EVENT_HSP_META;
484             event[1] = size + 2;
485             event[2] = HSP_SUBEVENT_AG_INDICATION;
486             event[3] = size;
487             (*hsp_hs_callback)(HCI_EVENT_PACKET, 0, event, size+4);
488         }
489         hsp_run();
490         return;
491     }
492 
493     if (packet_type != HCI_EVENT_PACKET) return;
494     uint8_t event = hci_event_packet_get_type(packet);
495     bd_addr_t event_addr;
496     uint16_t handle;
497 
498     switch (event) {
499         case HCI_EVENT_SYNCHRONOUS_CONNECTION_COMPLETE:{
500             if (hsp_state < HSP_RFCOMM_CONNECTION_ESTABLISHED) return;
501             int index = 2;
502             uint8_t status = packet[index++];
503             sco_handle = little_endian_read_16(packet, index);
504             index+=2;
505             bd_addr_t address;
506             memcpy(address, &packet[index], 6);
507             index+=6;
508             uint8_t link_type = packet[index++];
509             uint8_t transmission_interval = packet[index++];  // measured in slots
510             uint8_t retransmission_interval = packet[index++];// measured in slots
511             uint16_t rx_packet_length = little_endian_read_16(packet, index); // measured in bytes
512             index+=2;
513             uint16_t tx_packet_length = little_endian_read_16(packet, index); // measured in bytes
514             index+=2;
515             uint8_t air_mode = packet[index];
516 
517             if (status != 0){
518                 log_error("(e)SCO Connection failed, status %u", status);
519                 emit_event_audio_connected(status, sco_handle);
520                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED ;
521                 break;
522             }
523 
524             switch (link_type){
525                 case 0x00:
526                     log_info("SCO Connection established.");
527                     if (transmission_interval != 0) log_error("SCO Connection: transmission_interval not zero: %d.", transmission_interval);
528                     if (retransmission_interval != 0) log_error("SCO Connection: retransmission_interval not zero: %d.", retransmission_interval);
529                     if (rx_packet_length != 0) log_error("SCO Connection: rx_packet_length not zero: %d.", rx_packet_length);
530                     if (tx_packet_length != 0) log_error("SCO Connection: tx_packet_length not zero: %d.", tx_packet_length);
531                     break;
532                 case 0x02:
533                     log_info("eSCO Connection established.");
534                     break;
535                 default:
536                     log_error("(e)SCO reserved link_type 0x%2x", link_type);
537                     break;
538             }
539             log_info("sco_handle 0x%2x, address %s, transmission_interval %u slots, retransmission_interval %u slots, "
540                  " rx_packet_length %u bytes, tx_packet_length %u bytes, air_mode 0x%2x (0x02 == CVSD)", sco_handle,
541                  bd_addr_to_str(address), transmission_interval, retransmission_interval, rx_packet_length, tx_packet_length, air_mode);
542 
543             hsp_state = HSP_AUDIO_CONNECTION_ESTABLISHED;
544             emit_event_audio_connected(status, sco_handle);
545             break;
546         }
547 
548         case RFCOMM_EVENT_INCOMING_CONNECTION:
549             // data: event (8), len(8), address(48), channel (8), rfcomm_cid (16)
550             if (hsp_state != HSP_IDLE) return;
551 
552             reverse_bd_addr(&packet[2], event_addr);
553             rfcomm_cid = little_endian_read_16(packet, 9);
554             log_info("RFCOMM channel %u requested for %s", packet[8], bd_addr_to_str(event_addr));
555             hsp_state = HSP_W4_RFCOMM_CONNECTED;
556             rfcomm_accept_connection(rfcomm_cid);
557             break;
558 
559         case RFCOMM_EVENT_CHANNEL_OPENED:
560             // printf("RFCOMM_EVENT_CHANNEL_OPENED packet_handler type %u, packet[0] %x\n", packet_type, packet[0]);
561             // data: event(8), len(8), status (8), address (48), handle(16), server channel(8), rfcomm_cid(16), max frame size(16)
562             if (hsp_state != HSP_W4_RFCOMM_CONNECTED) return;
563             if (packet[2]) {
564                 log_info("RFCOMM channel open failed, status %u", packet[2]);
565                 hsp_state = HSP_IDLE;
566                 hsp_hs_reset_state();
567             } else {
568                 // data: event(8) , len(8), status (8), address (48), handle (16), server channel(8), rfcomm_cid(16), max frame size(16)
569                 rfcomm_handle = little_endian_read_16(packet, 9);
570                 rfcomm_cid = little_endian_read_16(packet, 12);
571                 mtu = little_endian_read_16(packet, 14);
572                 log_info("RFCOMM channel open succeeded. New RFCOMM Channel ID %u, max frame size %u, handle %02x", rfcomm_cid, mtu, rfcomm_handle);
573                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
574             }
575             emit_event(HSP_SUBEVENT_RFCOMM_CONNECTION_COMPLETE, packet[2]);
576             break;
577 
578         case RFCOMM_EVENT_CAN_SEND_NOW:
579             hsp_run();
580             break;
581 
582         case HCI_EVENT_DISCONNECTION_COMPLETE:
583             handle = little_endian_read_16(packet,3);
584             if (handle == sco_handle){
585                 sco_handle = 0;
586                 hsp_state = HSP_RFCOMM_CONNECTION_ESTABLISHED;
587                 emit_event(HSP_SUBEVENT_AUDIO_DISCONNECTION_COMPLETE,0);
588                 break;
589             }
590             if (handle == rfcomm_handle) {
591                 rfcomm_handle = 0;
592                 hsp_state = HSP_IDLE;
593                 emit_event(HSP_SUBEVENT_RFCOMM_DISCONNECTION_COMPLETE,0);
594                 hsp_hs_reset_state();
595             }
596             break;
597 
598         case RFCOMM_EVENT_CHANNEL_CLOSED:
599             hsp_hs_reset_state();
600             hsp_hs_callback(HCI_EVENT_PACKET, 0, packet, size);
601             break;
602 
603         default:
604             break;
605     }
606 
607     hsp_run();
608 }
609 
610 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
611     UNUSED(packet_type);
612     UNUSED(channel);
613     UNUSED(size);
614 
615     switch (hci_event_packet_get_type(packet)){
616         case SDP_EVENT_QUERY_RFCOMM_SERVICE:
617             channel_nr = sdp_event_query_rfcomm_service_get_rfcomm_channel(packet);
618             log_info("** Service name: '%s', RFCOMM port %u", sdp_event_query_rfcomm_service_get_name(packet), channel_nr);
619             break;
620         case SDP_EVENT_QUERY_COMPLETE:
621             if (channel_nr > 0){
622                 hsp_state = HSP_W4_RFCOMM_CONNECTED;
623                 log_info("HSP: SDP_QUERY_COMPLETE. RFCOMM create channel, addr %s, rfcomm channel nr %d", bd_addr_to_str(remote), channel_nr);
624                 rfcomm_create_channel(packet_handler, remote, channel_nr, NULL);
625                 break;
626             }
627             hsp_hs_reset_state();
628             log_info("Service not found, status %u.", sdp_event_query_complete_get_status(packet));
629             break;
630     }
631 }
632 
633 void hsp_hs_send_button_press(void){
634     if (hsp_state < HSP_RFCOMM_CONNECTION_ESTABLISHED || hsp_state >= HSP_W4_RFCOMM_DISCONNECTED) return;
635     hs_send_button_press = 1;
636     hsp_run();
637 }
638