xref: /btstack/src/classic/hfp.c (revision 8deec6605cc90fefa48d3aafe96338c6d0034607)
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 BLUEKITCHEN
24  * GMBH 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__ "hfp.c"
39 
40 
41 #include "btstack_config.h"
42 
43 #include <stdint.h>
44 #include <stdio.h>
45 #include <string.h>
46 #include <inttypes.h>
47 
48 #include "bluetooth_sdp.h"
49 #include "btstack_debug.h"
50 #include "btstack_event.h"
51 #include "btstack_memory.h"
52 #include "btstack_run_loop.h"
53 #include "classic/sdp_client_rfcomm.h"
54 #include "classic/sdp_server.h"
55 #include "classic/sdp_util.h"
56 #include "classic/sdp_client.h"
57 #include "hci.h"
58 #include "hci_cmd.h"
59 #include "hci_dump.h"
60 
61 #if defined(ENABLE_CC256X_ASSISTED_HFP) && !defined(ENABLE_SCO_OVER_PCM)
62 #error "Assisted HFP is only possible over PCM/I2S. Please add define: ENABLE_SCO_OVER_PCM"
63 #endif
64 
65 #if defined(ENABLE_BCM_PCM_WBS) && !defined(ENABLE_SCO_OVER_PCM)
66 #error "WBS for PCM is only possible over PCM/I2S. Please add define: ENABLE_SCO_OVER_PCM"
67 #endif
68 
69 #define HFP_HF_FEATURES_SIZE 10
70 #define HFP_AG_FEATURES_SIZE 12
71 
72 typedef struct {
73     hfp_role_t local_role;
74     bd_addr_t  remote_address;
75 } hfp_sdp_query_context_t;
76 
77 // globals
78 
79 static btstack_linked_list_t hfp_connections ;
80 
81 static btstack_packet_handler_t hfp_hf_callback;
82 static btstack_packet_handler_t hfp_ag_callback;
83 
84 static btstack_packet_handler_t hfp_hf_rfcomm_packet_handler;
85 static btstack_packet_handler_t hfp_ag_rfcomm_packet_handler;
86 
87 static uint16_t hfp_allowed_sco_packet_types;
88 static hfp_connection_t * hfp_sco_establishment_active;
89 
90 static hfp_sdp_query_context_t                 hfp_sdp_query_context;
91 static btstack_context_callback_registration_t hfp_sdp_query_request;
92 
93 
94 
95 
96 
97 // custom commands
98 static btstack_linked_list_t hfp_custom_commands_ag;
99 static btstack_linked_list_t hfp_custom_commands_hf;
100 
101 // prototypes
102 static hfp_link_settings_t hfp_next_link_setting_for_connection(hfp_link_settings_t current_setting, hfp_connection_t * hfp_connection, uint8_t eSCO_S4_supported);
103 static void parse_sequence(hfp_connection_t * context);
104 
105 
106 #define CODEC_MASK_CVSD   (1 << HFP_CODEC_CVSD)
107 #define CODEC_MASK_OTHER ((1 << HFP_CODEC_MSBC) | (1 << HFP_CODEC_LC3_SWB))
108 
109 static const struct {
110     const uint16_t max_latency;
111     const uint8_t  retransmission_effort;
112     const uint16_t packet_types;
113     const bool     eSCO;
114     const uint8_t  codec_mask;
115 } hfp_link_settings [] = {
116         {0x0004, 0xff, SCO_PACKET_TYPES_HV1,  false, CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_D0
117         {0x0005, 0xff, SCO_PACKET_TYPES_HV3,  false, CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_D1
118         {0x0007, 0x01, SCO_PACKET_TYPES_EV3,  true,  CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_S1
119         {0x0007, 0x01, SCO_PACKET_TYPES_2EV3, true,  CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_S2
120         {0x000a, 0x01, SCO_PACKET_TYPES_2EV3, true,  CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_S3
121         {0x000c, 0x02, SCO_PACKET_TYPES_2EV3, true,  CODEC_MASK_CVSD }, // HFP_LINK_SETTINGS_S4
122         {0x0008, 0x02, SCO_PACKET_TYPES_EV3,  true,  CODEC_MASK_OTHER}, // HFP_LINK_SETTINGS_T1
123         {0x000d, 0x02, SCO_PACKET_TYPES_2EV3, true,  CODEC_MASK_OTHER}  // HFP_LINK_SETTINGS_T2
124 };
125 
126 // table 5.8 'mandatory safe settings' for eSCO + similar entries for SCO
127 static const struct hfp_mandatory_safe_setting {
128     const uint8_t codec_mask;
129     const bool secure_connection_in_use;
130     hfp_link_settings_t link_setting;
131 } hfp_mandatory_safe_settings[] = {
132         { CODEC_MASK_CVSD,  false, HFP_LINK_SETTINGS_D1},
133         { CODEC_MASK_CVSD,  true,  HFP_LINK_SETTINGS_D1},
134         { CODEC_MASK_CVSD,  false, HFP_LINK_SETTINGS_S1},
135         { CODEC_MASK_CVSD,  true,  HFP_LINK_SETTINGS_S4},
136         { CODEC_MASK_OTHER, false, HFP_LINK_SETTINGS_T1},
137         { CODEC_MASK_OTHER, true,  HFP_LINK_SETTINGS_T2},
138 };
139 
140 static const char * hfp_hf_features[] = {
141         "EC and/or NR function",
142         "Three-way calling",
143         "CLI presentation capability",
144         "Voice recognition activation",
145         "Remote volume control",
146 
147         "Enhanced call status",
148         "Enhanced call control",
149 
150         "Codec negotiation",
151 
152         "HF Indicators",
153         "eSCO S4 (and T2) Settings Supported",
154         "Reserved for future definition"
155 };
156 
157 static const char * hfp_ag_features[] = {
158         "Three-way calling",
159         "EC and/or NR function",
160         "Voice recognition function",
161         "In-band ring tone capability",
162         "Attach a number to a voice tag",
163         "Ability to reject a call",
164         "Enhanced call status",
165         "Enhanced call control",
166         "Extended Error Result Codes",
167         "Codec negotiation",
168         "HF Indicators",
169         "eSCO S4 (and T2) Settings Supported",
170         "Reserved for future definition"
171 };
172 
173 static const char * hfp_enhanced_call_dir[] = {
174         "outgoing",
175         "incoming"
176 };
177 
178 static const char * hfp_enhanced_call_status[] = {
179         "active",
180         "held",
181         "outgoing dialing",
182         "outgoing alerting",
183         "incoming",
184         "incoming waiting",
185         "call held by response and hold"
186 };
187 
188 static const char * hfp_enhanced_call_mode[] = {
189         "voice",
190         "data",
191         "fax"
192 };
193 
194 static const char * hfp_enhanced_call_mpty[] = {
195         "not a conference call",
196         "conference call"
197 };
198 
199 const char * hfp_enhanced_call_dir2str(uint16_t index){
200     if (index <= HFP_ENHANCED_CALL_DIR_INCOMING) return hfp_enhanced_call_dir[index];
201     return "not defined";
202 }
203 
204 const char * hfp_enhanced_call_status2str(uint16_t index){
205     if (index <= HFP_ENHANCED_CALL_STATUS_CALL_HELD_BY_RESPONSE_AND_HOLD) return hfp_enhanced_call_status[index];
206     return "not defined";
207 }
208 
209 const char * hfp_enhanced_call_mode2str(uint16_t index){
210     if (index <= HFP_ENHANCED_CALL_MODE_FAX) return hfp_enhanced_call_mode[index];
211     return "not defined";
212 }
213 
214 const char * hfp_enhanced_call_mpty2str(uint16_t index){
215     if (index <= HFP_ENHANCED_CALL_MPTY_CONFERENCE_CALL) return hfp_enhanced_call_mpty[index];
216     return "not defined";
217 }
218 
219 static uint16_t hfp_parse_indicator_index(hfp_connection_t * hfp_connection){
220     uint16_t index = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
221 
222     if (index > HFP_MAX_NUM_INDICATORS){
223         log_info("ignoring invalid indicator index bigger then HFP_MAX_NUM_INDICATORS");
224         return HFP_MAX_NUM_INDICATORS - 1;
225     }
226 
227     // indicator index enumeration starts with 1, we substract 1 to store in array with starting index 0
228     if (index > 0){
229         index -= 1;
230     } else {
231         log_info("ignoring invalid indicator index 0");
232         return 0;
233     }
234     return index;
235 }
236 
237 static void hfp_next_indicators_index(hfp_connection_t * hfp_connection){
238     if (hfp_connection->parser_item_index < HFP_MAX_NUM_INDICATORS - 1){
239         hfp_connection->parser_item_index++;
240     } else {
241         log_info("Ignoring additional indicator");
242     }
243 }
244 
245 static void hfp_next_codec_index(hfp_connection_t * hfp_connection){
246     if (hfp_connection->parser_item_index < HFP_MAX_NUM_CODECS - 1){
247         hfp_connection->parser_item_index++;
248     } else {
249         log_info("Ignoring additional codec index");
250     }
251 }
252 
253 static void hfp_next_remote_call_services_index(hfp_connection_t * hfp_connection){
254     if (hfp_connection->remote_call_services_index < HFP_MAX_NUM_CALL_SERVICES - 1){
255         hfp_connection->remote_call_services_index++;
256     } else {
257         log_info("Ignoring additional remote_call_services");
258     }
259 }
260 
261 const char * hfp_hf_feature(int index){
262     if (index > HFP_HF_FEATURES_SIZE){
263         return hfp_hf_features[HFP_HF_FEATURES_SIZE];
264     }
265     return hfp_hf_features[index];
266 }
267 
268 const char * hfp_ag_feature(int index){
269     if (index > HFP_AG_FEATURES_SIZE){
270         return hfp_ag_features[HFP_AG_FEATURES_SIZE];
271     }
272     return hfp_ag_features[index];
273 }
274 
275 int send_str_over_rfcomm(uint16_t cid, const char * command){
276     if (!rfcomm_can_send_packet_now(cid)) return 1;
277     log_info("HFP_TX %s", command);
278     int err = rfcomm_send(cid, (uint8_t*) command, (uint16_t) strlen(command));
279     if (err){
280         log_error("rfcomm_send -> error 0x%02x \n", err);
281     }
282 #ifdef ENABLE_HFP_AT_MESSAGES
283     hfp_connection_t * hfp_connection = get_hfp_connection_context_for_rfcomm_cid(cid);
284     hfp_emit_string_event(hfp_connection, HFP_SUBEVENT_AT_MESSAGE_SENT, command);
285 #endif
286     return 1;
287 }
288 
289 int hfp_supports_codec(uint8_t codec, int codecs_nr, uint8_t * codecs){
290 
291     // mSBC requires support for eSCO connections
292     if ((codec == HFP_CODEC_MSBC) && !hci_extended_sco_link_supported()) return 0;
293 
294     int i;
295     for (i = 0; i < codecs_nr; i++){
296         if (codecs[i] != codec) continue;
297         return 1;
298     }
299     return 0;
300 }
301 
302 void hfp_hf_drop_mSBC_if_eSCO_not_supported(uint8_t * codecs, uint8_t * codecs_nr){
303     if (hci_extended_sco_link_supported()) return;
304     uint8_t i;
305     int filtered_codec_count = 0;
306     for (i=0; i < *codecs_nr; i++){
307         if (codecs[i] != HFP_CODEC_MSBC) {
308             codecs[filtered_codec_count++] = codecs[i];
309         }
310     }
311     *codecs_nr = filtered_codec_count;
312 }
313 
314 // UTILS
315 int get_bit(uint16_t bitmap, int position){
316     return (bitmap >> position) & 1;
317 }
318 
319 int store_bit(uint32_t bitmap, int position, uint8_t value){
320     if (value){
321         bitmap |= 1 << position;
322     } else {
323         bitmap &= ~ (1 << position);
324     }
325     return bitmap;
326 }
327 
328 int join(char * buffer, int buffer_size, uint8_t * values, int values_nr){
329     if (buffer_size < (values_nr * 3)) return 0;
330     int i;
331     int offset = 0;
332     for (i = 0; i < (values_nr-1); i++) {
333       offset += snprintf(buffer+offset, buffer_size-offset, "%d,", values[i]); // puts string into buffer
334     }
335     if (i<values_nr){
336         offset += snprintf(buffer+offset, buffer_size-offset, "%d", values[i]);
337     }
338     return offset;
339 }
340 
341 int join_bitmap(char * buffer, int buffer_size, uint32_t values, int values_nr){
342     if (buffer_size < (values_nr * 3)) return 0;
343 
344     int i;
345     int offset = 0;
346     for (i = 0; i < (values_nr-1); i++) {
347       offset += snprintf(buffer+offset, buffer_size-offset, "%d,", get_bit(values,i)); // puts string into buffer
348     }
349 
350     if (i<values_nr){
351         offset += snprintf(buffer+offset, buffer_size-offset, "%d", get_bit(values,i));
352     }
353     return offset;
354 }
355 static void hfp_emit_event_for_role(hfp_role_t local_role, uint8_t * packet, uint16_t size){
356     switch (local_role){
357         case HFP_ROLE_HF:
358             (*hfp_hf_callback)(HCI_EVENT_PACKET, 0, packet, size);
359             break;
360         case HFP_ROLE_AG:
361             (*hfp_ag_callback)(HCI_EVENT_PACKET, 0, packet, size);
362             break;
363         default:
364             btstack_unreachable();
365             break;
366     }
367 }
368 
369 static void hfp_emit_event_for_context(hfp_connection_t * hfp_connection, uint8_t * packet, uint16_t size){
370     if (!hfp_connection) return;
371     hfp_emit_event_for_role(hfp_connection->local_role, packet, size);
372 }
373 
374 void hfp_emit_simple_event(hfp_connection_t * hfp_connection, uint8_t event_subtype){
375     hci_con_handle_t acl_handle = (hfp_connection != NULL) ? hfp_connection->acl_handle : HCI_CON_HANDLE_INVALID;
376     uint8_t event[5];
377     event[0] = HCI_EVENT_HFP_META;
378     event[1] = sizeof(event) - 2;
379     event[2] = event_subtype;
380     little_endian_store_16(event, 3, acl_handle);
381     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
382 }
383 
384 void hfp_emit_event(hfp_connection_t * hfp_connection, uint8_t event_subtype, uint8_t value){
385     hci_con_handle_t acl_handle = (hfp_connection != NULL) ? hfp_connection->acl_handle : HCI_CON_HANDLE_INVALID;
386     uint8_t event[6];
387     event[0] = HCI_EVENT_HFP_META;
388     event[1] = sizeof(event) - 2;
389     event[2] = event_subtype;
390     little_endian_store_16(event, 3, acl_handle);
391     event[5] = value; // status 0 == OK
392     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
393 }
394 
395 void hfp_emit_voice_recognition_enabled(hfp_connection_t * hfp_connection, uint8_t status){
396     btstack_assert(hfp_connection != NULL);
397 
398     uint8_t event[7];
399     event[0] = HCI_EVENT_HFP_META;
400     event[1] = sizeof(event) - 2;
401     event[2] = HFP_SUBEVENT_VOICE_RECOGNITION_ACTIVATED;
402 
403     little_endian_store_16(event, 3, hfp_connection->acl_handle);
404     event[5] = status; // 0:success
405     event[6] = hfp_connection->enhanced_voice_recognition_enabled ? 1 : 0;
406     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
407 }
408 
409 void hfp_emit_voice_recognition_disabled(hfp_connection_t * hfp_connection, uint8_t status){
410     btstack_assert(hfp_connection != NULL);
411 
412     uint8_t event[6];
413     event[0] = HCI_EVENT_HFP_META;
414     event[1] = sizeof(event) - 2;
415     event[2] = HFP_SUBEVENT_VOICE_RECOGNITION_DEACTIVATED;
416 
417     little_endian_store_16(event, 3, hfp_connection->acl_handle);
418     event[5] = status; // 0:success
419     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
420 }
421 
422 void hfp_emit_enhanced_voice_recognition_hf_ready_for_audio_event(hfp_connection_t * hfp_connection, uint8_t status){
423     hci_con_handle_t acl_handle = (hfp_connection != NULL) ? hfp_connection->acl_handle : HCI_CON_HANDLE_INVALID;
424 
425     uint8_t event[6];
426     event[0] = HCI_EVENT_HFP_META;
427     event[1] = sizeof(event) - 2;
428     event[2] = HFP_SUBEVENT_ENHANCED_VOICE_RECOGNITION_HF_READY_FOR_AUDIO;
429     little_endian_store_16(event, 3, acl_handle);
430     event[5] = status;
431     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
432 }
433 
434 void hfp_emit_enhanced_voice_recognition_state_event(hfp_connection_t * hfp_connection, uint8_t status){
435     hci_con_handle_t acl_handle = (hfp_connection != NULL) ? hfp_connection->acl_handle : HCI_CON_HANDLE_INVALID;
436 
437     uint8_t event[6];
438     event[0] = HCI_EVENT_HFP_META;
439     event[1] = sizeof(event) - 2;
440     switch (hfp_connection->ag_vra_state){
441         case HFP_VOICE_RECOGNITION_STATE_AG_READY_TO_ACCEPT_AUDIO_INPUT:
442             event[2] = HFP_SUBEVENT_ENHANCED_VOICE_RECOGNITION_AG_READY_TO_ACCEPT_AUDIO_INPUT;
443             break;
444         case HFP_VOICE_RECOGNITION_STATE_AG_IS_STARTING_SOUND:
445             event[2] = HFP_SUBEVENT_ENHANCED_VOICE_RECOGNITION_AG_IS_STARTING_SOUND;
446             break;
447         case HFP_VOICE_RECOGNITION_STATE_AG_IS_PROCESSING_AUDIO_INPUT:
448             event[2] = HFP_SUBEVENT_ENHANCED_VOICE_RECOGNITION_AG_IS_PROCESSING_AUDIO_INPUT;
449             break;
450         default:
451             btstack_unreachable();
452             break;
453     }
454 
455     little_endian_store_16(event, 3, acl_handle);
456     event[5] = status;
457     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
458 }
459 
460 void hfp_emit_slc_connection_event(hfp_role_t local_role, uint8_t status, hci_con_handle_t con_handle, bd_addr_t addr){
461     uint8_t event[12];
462     int pos = 0;
463     event[pos++] = HCI_EVENT_HFP_META;
464     event[pos++] = sizeof(event) - 2;
465     event[pos++] = HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_ESTABLISHED;
466     little_endian_store_16(event, pos, con_handle);
467     pos += 2;
468     event[pos++] = status; // status 0 == OK
469     reverse_bd_addr(addr,&event[pos]);
470     pos += 6;
471     hfp_emit_event_for_role(local_role, event, sizeof(event));
472 }
473 
474 static void hfp_emit_audio_connection_released(hfp_connection_t * hfp_connection, hci_con_handle_t sco_handle){
475     btstack_assert(hfp_connection != NULL);
476     uint8_t event[7];
477     int pos = 0;
478     event[pos++] = HCI_EVENT_HFP_META;
479     event[pos++] = sizeof(event) - 2;
480     event[pos++] = HFP_SUBEVENT_AUDIO_CONNECTION_RELEASED;
481     little_endian_store_16(event, pos, hfp_connection->acl_handle);
482     pos += 2;
483     little_endian_store_16(event, pos, sco_handle);
484     pos += 2;
485     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
486 }
487 
488 void hfp_emit_sco_connection_established(hfp_connection_t *hfp_connection, uint8_t status, uint8_t negotiated_codec,
489                                          uint16_t rx_packet_length, uint16_t tx_packet_length) {
490     btstack_assert(hfp_connection != NULL);
491     uint8_t event[21];
492     int pos = 0;
493     event[pos++] = HCI_EVENT_HFP_META;
494     event[pos++] = sizeof(event) - 2;
495     event[pos++] = HFP_SUBEVENT_AUDIO_CONNECTION_ESTABLISHED;
496     little_endian_store_16(event, pos, hfp_connection->acl_handle);
497     pos += 2;
498     event[pos++] = status; // status 0 == OK
499     little_endian_store_16(event, pos, hfp_connection->sco_handle);
500     pos += 2;
501     reverse_bd_addr(hfp_connection->remote_addr,&event[pos]);
502     pos += 6;
503     event[pos++] = negotiated_codec;
504     little_endian_store_16(event, pos, hfp_connection->packet_types);
505     little_endian_store_16(event, pos, rx_packet_length);
506     pos += 2;
507     little_endian_store_16(event, pos, tx_packet_length);
508     pos += 2;
509     hfp_emit_event_for_context(hfp_connection, event, sizeof(event));
510 }
511 
512 void hfp_emit_string_event(hfp_connection_t * hfp_connection, uint8_t event_subtype, const char * value){
513     btstack_assert(hfp_connection != NULL);
514 #ifdef ENABLE_HFP_AT_MESSAGES
515     uint8_t event[256];
516 #else
517     uint8_t event[40];
518 #endif
519     uint16_t string_len = btstack_min((uint16_t) strlen(value), sizeof(event) - 6);
520     event[0] = HCI_EVENT_HFP_META;
521     event[1] = 4 + string_len;
522     event[2] = event_subtype;
523     little_endian_store_16(event, 3, hfp_connection->acl_handle);
524     memcpy((char*)&event[5], value, string_len);
525     event[5 + string_len] = 0;
526     hfp_emit_event_for_context(hfp_connection, event, 6 + string_len);
527 }
528 
529 btstack_linked_list_t * hfp_get_connections(void){
530     return (btstack_linked_list_t *) &hfp_connections;
531 }
532 
533 hfp_connection_t * get_hfp_connection_context_for_rfcomm_cid(uint16_t cid){
534     btstack_linked_list_iterator_t it;
535     btstack_linked_list_iterator_init(&it, hfp_get_connections());
536     while (btstack_linked_list_iterator_has_next(&it)){
537         hfp_connection_t * hfp_connection = (hfp_connection_t *)btstack_linked_list_iterator_next(&it);
538         if (hfp_connection->rfcomm_cid == cid){
539             return hfp_connection;
540         }
541     }
542     return NULL;
543 }
544 
545 hfp_connection_t * get_hfp_connection_context_for_bd_addr(bd_addr_t bd_addr, hfp_role_t hfp_role){
546     btstack_linked_list_iterator_t it;
547     btstack_linked_list_iterator_init(&it, hfp_get_connections());
548     while (btstack_linked_list_iterator_has_next(&it)){
549         hfp_connection_t * hfp_connection = (hfp_connection_t *)btstack_linked_list_iterator_next(&it);
550         if ((memcmp(hfp_connection->remote_addr, bd_addr, 6) == 0) && (hfp_connection->local_role == hfp_role)) {
551             return hfp_connection;
552         }
553     }
554     return NULL;
555 }
556 
557 hfp_connection_t * get_hfp_connection_context_for_sco_handle(uint16_t handle, hfp_role_t hfp_role){
558     btstack_linked_list_iterator_t it;
559     btstack_linked_list_iterator_init(&it, hfp_get_connections());
560     while (btstack_linked_list_iterator_has_next(&it)){
561         hfp_connection_t * hfp_connection = (hfp_connection_t *)btstack_linked_list_iterator_next(&it);
562         if ((hfp_connection->sco_handle == handle) && (hfp_connection->local_role == hfp_role)){
563             return hfp_connection;
564         }
565     }
566     return NULL;
567 }
568 
569 hfp_connection_t * get_hfp_connection_context_for_acl_handle(uint16_t handle, hfp_role_t hfp_role){
570     btstack_linked_list_iterator_t it;
571     btstack_linked_list_iterator_init(&it, hfp_get_connections());
572     while (btstack_linked_list_iterator_has_next(&it)){
573         hfp_connection_t * hfp_connection = (hfp_connection_t *)btstack_linked_list_iterator_next(&it);
574         if ((hfp_connection->acl_handle == handle) && (hfp_connection->local_role == hfp_role)){
575             return hfp_connection;
576         }
577     }
578     return NULL;
579 }
580 
581 
582 static void hfp_reset_voice_recognition(hfp_connection_t * hfp_connection){
583     btstack_assert(hfp_connection != NULL);
584     hfp_voice_recognition_activation_status_t current_vra_state = hfp_connection->vra_state;
585     hfp_connection->vra_state = HFP_VRA_VOICE_RECOGNITION_OFF;
586 
587     if (current_vra_state != HFP_VRA_VOICE_RECOGNITION_OFF){
588         hfp_emit_voice_recognition_disabled(hfp_connection, ERROR_CODE_SUCCESS);
589     } else if (hfp_connection->vra_state_requested != HFP_VRA_VOICE_RECOGNITION_OFF){
590         hfp_emit_voice_recognition_disabled(hfp_connection, ERROR_CODE_SUCCESS);
591     }
592 
593     hfp_connection->vra_state_requested = HFP_VRA_VOICE_RECOGNITION_OFF;
594     hfp_connection->activate_voice_recognition = false;
595     hfp_connection->deactivate_voice_recognition = false;
596     hfp_connection->enhanced_voice_recognition_enabled = false;
597     hfp_connection->ag_vra_status = 0;
598     hfp_connection->ag_vra_state = HFP_VOICE_RECOGNITION_STATE_AG_READY;
599 }
600 
601 void hfp_reset_context_flags(hfp_connection_t * hfp_connection){
602     if (!hfp_connection) return;
603     hfp_connection->ok_pending = 0;
604     hfp_connection->send_error = 0;
605 
606     hfp_connection->found_equal_sign = false;
607 
608     hfp_connection->change_status_update_for_individual_ag_indicators = 0;
609     hfp_connection->operator_name_changed = 0;
610 
611     hfp_connection->enable_extended_audio_gateway_error_report = 0;
612     hfp_connection->extended_audio_gateway_error = 0;
613 
614     // establish codecs hfp_connection
615     hfp_connection->suggested_codec = 0;
616     hfp_connection->negotiated_codec = 0;
617     hfp_connection->codec_confirmed = 0;
618 
619     hfp_connection->establish_audio_connection = 0;
620     hfp_connection->call_waiting_notification_enabled = 0;
621     hfp_connection->command = HFP_CMD_NONE;
622     hfp_connection->enable_status_update_for_ag_indicators = 0xFF;
623     hfp_connection->clip_have_alpha = false;
624     hfp_reset_voice_recognition(hfp_connection);
625 }
626 
627 static hfp_connection_t * create_hfp_connection_context(void){
628     hfp_connection_t * hfp_connection = btstack_memory_hfp_connection_get();
629     if (!hfp_connection) return NULL;
630 
631     hfp_connection->state = HFP_IDLE;
632     hfp_connection->call_state = HFP_CALL_IDLE;
633     hfp_connection->codecs_state = HFP_CODECS_IDLE;
634 
635     hfp_connection->parser_state = HFP_PARSER_CMD_HEADER;
636 
637     hfp_connection->acl_handle = HCI_CON_HANDLE_INVALID;
638     hfp_connection->sco_handle = HCI_CON_HANDLE_INVALID;
639 
640     hfp_reset_context_flags(hfp_connection);
641 
642     btstack_linked_list_add(&hfp_connections, (btstack_linked_item_t*)hfp_connection);
643     return hfp_connection;
644 }
645 
646 void hfp_finalize_connection_context(hfp_connection_t * hfp_connection){
647     btstack_linked_list_remove(&hfp_connections, (btstack_linked_item_t*) hfp_connection);
648     btstack_memory_hfp_connection_free(hfp_connection);
649 }
650 
651 static hfp_connection_t * hfp_create_connection(bd_addr_t bd_addr, hfp_role_t local_role){
652     hfp_connection_t * hfp_connection = get_hfp_connection_context_for_bd_addr(bd_addr, local_role);
653     if (hfp_connection) return  hfp_connection;
654     hfp_connection = create_hfp_connection_context();
655     if (!hfp_connection) {
656         return NULL;
657     }
658     (void)memcpy(hfp_connection->remote_addr, bd_addr, 6);
659     hfp_connection->local_role = local_role;
660     log_info("Create HFP context %p: role %u, addr %s", hfp_connection, local_role, bd_addr_to_str(bd_addr));
661 
662     return hfp_connection;
663 }
664 
665 /* @param network.
666  * 0 == no ability to reject a call.
667  * 1 == ability to reject a call.
668  */
669 
670 /* @param suported_features
671  * HF bit 0: EC and/or NR function (yes/no, 1 = yes, 0 = no)
672  * HF bit 1: Call waiting or three-way calling(yes/no, 1 = yes, 0 = no)
673  * HF bit 2: CLI presentation capability (yes/no, 1 = yes, 0 = no)
674  * HF bit 3: Voice recognition activation (yes/no, 1= yes, 0 = no)
675  * HF bit 4: Remote volume control (yes/no, 1 = yes, 0 = no)
676  * HF bit 5: Wide band speech (yes/no, 1 = yes, 0 = no)
677  */
678  /* Bit position:
679  * AG bit 0: Three-way calling (yes/no, 1 = yes, 0 = no)
680  * AG bit 1: EC and/or NR function (yes/no, 1 = yes, 0 = no)
681  * AG bit 2: Voice recognition function (yes/no, 1 = yes, 0 = no)
682  * AG bit 3: In-band ring tone capability (yes/no, 1 = yes, 0 = no)
683  * AG bit 4: Attach a phone number to a voice tag (yes/no, 1 = yes, 0 = no)
684  * AG bit 5: Wide band speech (yes/no, 1 = yes, 0 = no)
685  */
686 
687 void hfp_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint16_t service_uuid, int rfcomm_channel_nr, const char * name){
688     uint8_t* attribute;
689     de_create_sequence(service);
690 
691     // 0x0000 "Service Record Handle"
692     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
693     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
694 
695     // 0x0001 "Service Class ID List"
696     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
697     attribute = de_push_sequence(service);
698     {
699         //  "UUID for Service"
700         de_add_number(attribute, DE_UUID, DE_SIZE_16, service_uuid);
701         de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_GENERIC_AUDIO);
702     }
703     de_pop_sequence(service, attribute);
704 
705     // 0x0004 "Protocol Descriptor List"
706     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
707     attribute = de_push_sequence(service);
708     {
709         uint8_t* l2cpProtocol = de_push_sequence(attribute);
710         {
711             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
712         }
713         de_pop_sequence(attribute, l2cpProtocol);
714 
715         uint8_t* rfcomm = de_push_sequence(attribute);
716         {
717             de_add_number(rfcomm,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_RFCOMM);  // rfcomm_service
718             de_add_number(rfcomm,  DE_UINT, DE_SIZE_8,  rfcomm_channel_nr);  // rfcomm channel
719         }
720         de_pop_sequence(attribute, rfcomm);
721     }
722     de_pop_sequence(service, attribute);
723 
724 
725     // 0x0005 "Public Browse Group"
726     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
727     attribute = de_push_sequence(service);
728     {
729         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
730     }
731     de_pop_sequence(service, attribute);
732 
733     // 0x0009 "Bluetooth Profile Descriptor List"
734     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
735     attribute = de_push_sequence(service);
736     {
737         uint8_t *sppProfile = de_push_sequence(attribute);
738         {
739             de_add_number(sppProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_HANDSFREE);
740             de_add_number(sppProfile,  DE_UINT, DE_SIZE_16, 0x0108); // Verision 1.8
741         }
742         de_pop_sequence(attribute, sppProfile);
743     }
744     de_pop_sequence(service, attribute);
745 
746     // 0x0100 "Service Name"
747     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
748     de_add_data(service,  DE_STRING, (uint16_t) strlen(name), (uint8_t *) name);
749 }
750 
751 static void hfp_handle_slc_setup_error(hfp_connection_t * hfp_connection, uint8_t status){
752     // cache fields for event
753     hfp_role_t local_role = hfp_connection->local_role;
754     bd_addr_t remote_addr;
755     // cppcheck-suppress uninitvar ; remote_addr is reported as uninitialized although it's the destination of the memcpy
756     (void)memcpy(remote_addr, hfp_connection->remote_addr, 6);
757     // finalize connection struct
758     hfp_finalize_connection_context(hfp_connection);
759     // emit event
760     hfp_emit_slc_connection_event(local_role, status, HCI_CON_HANDLE_INVALID, remote_addr);
761 }
762 
763 static void handle_query_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
764     UNUSED(packet_type);    // ok: handling own sdp events
765     UNUSED(channel);        // ok: no channel
766     UNUSED(size);           // ok: handling own sdp events
767 
768     hfp_connection_t * hfp_connection = get_hfp_connection_context_for_bd_addr(hfp_sdp_query_context.remote_address, hfp_sdp_query_context.local_role);
769     if (hfp_connection == NULL) {
770         log_info("connection with %s and local role %d not found", hfp_sdp_query_context.remote_address, hfp_sdp_query_context.local_role);
771         return;
772     }
773 
774     switch (hci_event_packet_get_type(packet)){
775         case SDP_EVENT_QUERY_RFCOMM_SERVICE:
776             hfp_connection->rfcomm_channel_nr = sdp_event_query_rfcomm_service_get_rfcomm_channel(packet);
777             break;
778         case SDP_EVENT_QUERY_COMPLETE:
779             if (hfp_connection->rfcomm_channel_nr > 0){
780                 hfp_connection->state = HFP_W4_RFCOMM_CONNECTED;
781                 btstack_packet_handler_t packet_handler;
782                 switch (hfp_connection->local_role){
783                     case HFP_ROLE_AG:
784                         packet_handler = hfp_ag_rfcomm_packet_handler;
785                         break;
786                     case HFP_ROLE_HF:
787                         packet_handler = hfp_hf_rfcomm_packet_handler;
788                         break;
789                     default:
790                         btstack_assert(false);
791                         return;
792                 }
793 
794                 rfcomm_create_channel(packet_handler, hfp_connection->remote_addr, hfp_connection->rfcomm_channel_nr, NULL);
795 
796             } else {
797                 uint8_t status = sdp_event_query_complete_get_status(packet);
798                 if (status == ERROR_CODE_SUCCESS){
799                     // report service not found
800                     status = SDP_SERVICE_NOT_FOUND;
801                 }
802                 hfp_handle_slc_setup_error(hfp_connection, status);
803                 log_info("rfcomm service not found, status 0x%02x", status);
804             }
805 
806             // register the SDP Query request to check if there is another connection waiting for the query
807             // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
808             (void) sdp_client_register_query_callback(&hfp_sdp_query_request);
809             break;
810         default:
811             break;
812     }
813 }
814 
815 // returns 0 if unexpected error or no other link options remained, otherwise 1
816 static int hfp_handle_failed_sco_connection(uint8_t status){
817 
818     if (!hfp_sco_establishment_active){
819         log_info("(e)SCO Connection failed but not started by us");
820         return 0;
821     }
822 
823     log_info("(e)SCO Connection failed 0x%02x", status);
824     switch (status){
825         case ERROR_CODE_SCO_AIR_MODE_REJECTED:
826         case ERROR_CODE_SCO_INTERVAL_REJECTED:
827         case ERROR_CODE_SCO_OFFSET_REJECTED:
828         case ERROR_CODE_UNSPECIFIED_ERROR:
829         case ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE:
830         case ERROR_CODE_UNSUPPORTED_REMOTE_FEATURE_UNSUPPORTED_LMP_FEATURE:
831             break;
832         default:
833             return 0;
834     }
835 
836     // note: eSCO_S4 supported flag not available, but it's only relevant for highest CVSD link setting (and the current failed)
837     hfp_link_settings_t next_setting = hfp_next_link_setting_for_connection(hfp_sco_establishment_active->link_setting, hfp_sco_establishment_active, false);
838 
839     // handle no valid setting found
840     if (next_setting == HFP_LINK_SETTINGS_NONE) {
841         if (hfp_sco_establishment_active->negotiated_codec == HFP_CODEC_MSBC){
842             log_info("T2/T1 failed, fallback to CVSD - D1");
843             hfp_sco_establishment_active->negotiated_codec = HFP_CODEC_CVSD;
844             hfp_sco_establishment_active->sco_for_msbc_failed = 1;
845             hfp_sco_establishment_active->ag_send_common_codec = true;
846             hfp_sco_establishment_active->link_setting = HFP_LINK_SETTINGS_D1;
847         } else {
848             // no other options
849             return 0;
850         }
851     }
852 
853     log_info("e)SCO Connection: try new link_setting %d", next_setting);
854     hfp_sco_establishment_active->establish_audio_connection = 1;
855     hfp_sco_establishment_active->link_setting = next_setting;
856     hfp_sco_establishment_active = NULL;
857     return 1;
858 }
859 
860 void hfp_handle_hci_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, hfp_role_t local_role){
861     UNUSED(packet_type);
862     UNUSED(channel);    // ok: no channel
863     UNUSED(size);
864 
865     bd_addr_t event_addr;
866     hci_con_handle_t handle;
867     hfp_connection_t * hfp_connection = NULL;
868     uint8_t status;
869 
870     log_debug("HFP HCI event handler type %u, event type %x, size %u", packet_type, hci_event_packet_get_type(packet), size);
871 
872     switch (hci_event_packet_get_type(packet)) {
873 
874         case HCI_EVENT_CONNECTION_REQUEST:
875             switch(hci_event_connection_request_get_link_type(packet)){
876                 case 0: //  SCO
877                 case 2: // eSCO
878                     hci_event_connection_request_get_bd_addr(packet, event_addr);
879                     hfp_connection = get_hfp_connection_context_for_bd_addr(event_addr, local_role);
880                     if (!hfp_connection) break;
881                     if (hci_event_connection_request_get_link_type(packet) == 2){
882                         hfp_connection->accept_sco = 2;
883                     } else {
884                         hfp_connection->accept_sco = 1;
885                     }
886 #ifdef ENABLE_CC256X_ASSISTED_HFP
887                     hfp_cc256x_prepare_for_sco(hfp_connection);
888 #endif
889 #ifdef ENABLE_BCM_PCM_WBS
890                     hfp_bcm_prepare_for_sco(hfp_connection);
891 #endif
892 #ifdef ENABLE_RTK_PCM_WBS
893                     hfp_connection->rtk_send_sco_config = true;
894 #endif
895                     log_info("accept sco %u\n", hfp_connection->accept_sco);
896                     hfp_sco_establishment_active = hfp_connection;
897                     break;
898                 default:
899                     break;
900             }
901             break;
902 
903         case HCI_EVENT_COMMAND_STATUS:
904             if (hci_event_command_status_get_command_opcode(packet) == hci_setup_synchronous_connection.opcode) {
905                 if (hfp_sco_establishment_active == NULL) break;
906                 status = hci_event_command_status_get_status(packet);
907                 if (status == ERROR_CODE_SUCCESS) break;
908 
909                 hfp_connection = hfp_sco_establishment_active;
910                 if (hfp_handle_failed_sco_connection(status)) break;
911                 hfp_connection->establish_audio_connection = 0;
912                 hfp_connection->state = HFP_SERVICE_LEVEL_CONNECTION_ESTABLISHED;
913                 hfp_emit_sco_connection_established(hfp_connection, status,
914                                                     hfp_connection->negotiated_codec, 0, 0);
915             }
916             break;
917 
918         case HCI_EVENT_SYNCHRONOUS_CONNECTION_COMPLETE:{
919             if (hfp_sco_establishment_active == NULL) break;
920             hci_event_synchronous_connection_complete_get_bd_addr(packet, event_addr);
921             hfp_connection = get_hfp_connection_context_for_bd_addr(event_addr, local_role);
922             if (!hfp_connection) {
923                 log_error("HFP: connection does not exist for remote with addr %s.", bd_addr_to_str(event_addr));
924                 return;
925             }
926 
927             status = hci_event_synchronous_connection_complete_get_status(packet);
928             if (status != ERROR_CODE_SUCCESS){
929                 hfp_connection->accept_sco = 0;
930                 if (hfp_handle_failed_sco_connection(status)) break;
931 
932                 hfp_connection->establish_audio_connection = 0;
933                 hfp_connection->state = HFP_SERVICE_LEVEL_CONNECTION_ESTABLISHED;
934                 hfp_emit_sco_connection_established(hfp_connection, status,
935                                                     hfp_connection->negotiated_codec, 0, 0);
936                 break;
937             }
938 
939             uint16_t sco_handle = hci_event_synchronous_connection_complete_get_handle(packet);
940             uint8_t  link_type = hci_event_synchronous_connection_complete_get_link_type(packet);
941             uint8_t  transmission_interval = hci_event_synchronous_connection_complete_get_transmission_interval(packet);  // measured in slots
942             uint8_t  retransmission_interval = hci_event_synchronous_connection_complete_get_retransmission_interval(packet);// measured in slots
943             uint16_t rx_packet_length = hci_event_synchronous_connection_complete_get_rx_packet_length(packet); // measured in bytes
944             uint16_t tx_packet_length = hci_event_synchronous_connection_complete_get_tx_packet_length(packet); // measured in bytes
945 
946             switch (link_type){
947                 case 0x00:
948                     log_info("SCO Connection established.");
949                     if (transmission_interval != 0) log_error("SCO Connection: transmission_interval not zero: %d.", transmission_interval);
950                     if (retransmission_interval != 0) log_error("SCO Connection: retransmission_interval not zero: %d.", retransmission_interval);
951                     if (rx_packet_length != 0) log_error("SCO Connection: rx_packet_length not zero: %d.", rx_packet_length);
952                     if (tx_packet_length != 0) log_error("SCO Connection: tx_packet_length not zero: %d.", tx_packet_length);
953                     break;
954                 case 0x02:
955                     log_info("eSCO Connection established. \n");
956                     break;
957                 default:
958                     log_error("(e)SCO reserved link_type 0x%2x", link_type);
959                     break;
960             }
961 
962             log_info("sco_handle 0x%2x, address %s, transmission_interval %u slots, retransmission_interval %u slots, "
963                  " rx_packet_length %u bytes, tx_packet_length %u bytes, air_mode 0x%2x (0x02 == CVSD)\n", sco_handle,
964                  bd_addr_to_str(event_addr), transmission_interval, retransmission_interval, rx_packet_length, tx_packet_length,
965                  hci_event_synchronous_connection_complete_get_air_mode(packet));
966 
967             if (hfp_connection->state == HFP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN){
968                 log_info("SCO about to disconnect: HFP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN");
969                 hfp_connection->state = HFP_W2_DISCONNECT_SCO;
970                 break;
971             }
972             hfp_connection->sco_handle = sco_handle;
973             hfp_connection->establish_audio_connection = 0;
974 
975             hfp_connection->state = HFP_AUDIO_CONNECTION_ESTABLISHED;
976 
977             switch (hfp_connection->vra_state){
978                 case HFP_VRA_VOICE_RECOGNITION_ACTIVATED:
979                     hfp_connection->ag_audio_connection_opened_before_vra = false;
980                     break;
981                 default:
982                     hfp_connection->ag_audio_connection_opened_before_vra = true;
983                     break;
984             }
985             hfp_emit_sco_connection_established(hfp_connection, status,
986                                                 hfp_connection->negotiated_codec, rx_packet_length, tx_packet_length);
987             break;
988         }
989 
990         case HCI_EVENT_DISCONNECTION_COMPLETE:
991             handle = little_endian_read_16(packet,3);
992             hfp_connection = get_hfp_connection_context_for_sco_handle(handle, local_role);
993 
994             if (!hfp_connection) break;
995 
996 #ifdef ENABLE_CC256X_ASSISTED_HFP
997             hfp_connection->cc256x_send_wbs_disassociate = true;
998 #endif
999 #ifdef ENABLE_BCM_PCM_WBS
1000             hfp_connection->bcm_send_disable_wbs = true;
1001 #endif
1002             if (hfp_connection->sco_handle == handle){
1003                 hfp_connection->sco_handle = HCI_CON_HANDLE_INVALID;
1004                 hfp_connection->release_audio_connection = 0;
1005                 hfp_connection->state = HFP_SERVICE_LEVEL_CONNECTION_ESTABLISHED;
1006                 hfp_emit_audio_connection_released(hfp_connection, handle);
1007 
1008                 hfp_connection->ag_audio_connection_opened_before_vra = false;
1009 
1010                 if (hfp_connection->acl_handle == HCI_CON_HANDLE_INVALID){
1011                     hfp_reset_voice_recognition(hfp_connection);
1012                     hfp_emit_event(hfp_connection, HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_RELEASED, 0);
1013                     hfp_finalize_connection_context(hfp_connection);
1014                     break;
1015                 } else if (hfp_connection->release_slc_connection == 1){
1016                     hfp_connection->release_slc_connection = 0;
1017                     hfp_connection->state = HFP_W2_DISCONNECT_RFCOMM;
1018                     rfcomm_disconnect(hfp_connection->acl_handle);
1019                 }
1020             }
1021 
1022             if (hfp_connection->state == HFP_W4_SCO_DISCONNECTED_TO_SHUTDOWN){
1023                 // RFCOMM already closed -> remote power off
1024 #if defined(ENABLE_CC256X_ASSISTED_HFP) || defined (ENABLE_BCM_PCM_WBS)
1025                 hfp_connection->state = HFP_W4_WBS_SHUTDOWN;
1026 #else
1027                 hfp_finalize_connection_context(hfp_connection);
1028 #endif
1029                 break;
1030             }
1031             break;
1032 
1033         default:
1034             break;
1035     }
1036 }
1037 
1038 
1039 void hfp_handle_rfcomm_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, hfp_role_t local_role){
1040     UNUSED(packet_type);
1041     UNUSED(channel);    // ok: no channel
1042     UNUSED(size);
1043 
1044     bd_addr_t event_addr;
1045     uint16_t rfcomm_cid;
1046     hfp_connection_t * hfp_connection = NULL;
1047     uint8_t status;
1048 
1049     log_debug("HFP packet_handler type %u, event type %x, size %u", packet_type, hci_event_packet_get_type(packet), size);
1050 
1051     switch (hci_event_packet_get_type(packet)) {
1052 
1053         case RFCOMM_EVENT_INCOMING_CONNECTION:
1054             // data: event (8), len(8), address(48), channel (8), rfcomm_cid (16)
1055             rfcomm_event_incoming_connection_get_bd_addr(packet, event_addr);
1056             hfp_connection = hfp_create_connection(event_addr, local_role);
1057             if (!hfp_connection){
1058                 log_info("hfp: no memory to accept incoming connection - decline");
1059                 rfcomm_decline_connection(rfcomm_event_incoming_connection_get_rfcomm_cid(packet));
1060                 return;
1061             }
1062             if (hfp_connection->state != HFP_IDLE) {
1063                 log_error("hfp: incoming connection but not idle, reject");
1064                 rfcomm_decline_connection(rfcomm_event_incoming_connection_get_rfcomm_cid(packet));
1065                 return;
1066             }
1067 
1068             hfp_connection->rfcomm_cid = rfcomm_event_incoming_connection_get_rfcomm_cid(packet);
1069             hfp_connection->state = HFP_W4_RFCOMM_CONNECTED;
1070             rfcomm_accept_connection(hfp_connection->rfcomm_cid);
1071             break;
1072 
1073         case RFCOMM_EVENT_CHANNEL_OPENED:
1074             rfcomm_event_channel_opened_get_bd_addr(packet, event_addr);
1075 
1076             hfp_connection = get_hfp_connection_context_for_bd_addr(event_addr, local_role);
1077             btstack_assert(hfp_connection != NULL);
1078 
1079             if (hfp_connection->state != HFP_W4_RFCOMM_CONNECTED){
1080                 break;
1081             }
1082 
1083             status = rfcomm_event_channel_opened_get_status(packet);
1084             if (status != ERROR_CODE_SUCCESS) {
1085                 hfp_handle_slc_setup_error(hfp_connection, status);
1086                 break;
1087             }
1088 
1089             hfp_connection->acl_handle = rfcomm_event_channel_opened_get_con_handle(packet);
1090             hfp_connection->rfcomm_cid = rfcomm_event_channel_opened_get_rfcomm_cid(packet);
1091             hfp_connection->rfcomm_mtu = rfcomm_event_channel_opened_get_max_frame_size(packet);
1092             bd_addr_copy(hfp_connection->remote_addr, event_addr);
1093             hfp_connection->state = HFP_EXCHANGE_SUPPORTED_FEATURES;
1094 
1095             rfcomm_request_can_send_now_event(hfp_connection->rfcomm_cid);
1096             break;
1097 
1098         case RFCOMM_EVENT_CHANNEL_CLOSED:
1099             rfcomm_cid = little_endian_read_16(packet,2);
1100             hfp_connection = get_hfp_connection_context_for_rfcomm_cid(rfcomm_cid);
1101             if (!hfp_connection) break;
1102             switch (hfp_connection->state){
1103                 case HFP_W4_RFCOMM_DISCONNECTED_AND_RESTART:
1104                     hfp_connection->acl_handle = HCI_CON_HANDLE_INVALID;
1105                     hfp_connection->state = HFP_IDLE;
1106                     hfp_establish_service_level_connection(hfp_connection->remote_addr, hfp_connection->service_uuid, local_role);
1107                     break;
1108 
1109                 case HFP_AUDIO_CONNECTION_ESTABLISHED:
1110                     // service connection was released, this implicitly releases audio connection as well
1111                     hfp_connection->release_audio_connection = 0;
1112                     hfp_connection->acl_handle = HCI_CON_HANDLE_INVALID;
1113                     hfp_connection->state = HFP_W4_SCO_DISCONNECTED_TO_SHUTDOWN;
1114                     gap_disconnect(hfp_connection->sco_handle);
1115                     break;
1116 
1117                 default:
1118                     // regular case
1119                     hfp_reset_voice_recognition(hfp_connection);
1120                     hfp_emit_event(hfp_connection, HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_RELEASED, 0);
1121                     hfp_finalize_connection_context(hfp_connection);
1122                     break;
1123             }
1124             break;
1125 
1126         default:
1127             break;
1128     }
1129 }
1130 // translates command string into hfp_command_t CMD
1131 
1132 typedef struct {
1133     const char * command;
1134     hfp_command_t command_id;
1135 } hfp_command_entry_t;
1136 
1137 static hfp_command_entry_t hfp_ag_command_table[] = {
1138     { "AT+BAC=",   HFP_CMD_AVAILABLE_CODECS },
1139     { "AT+BCC",    HFP_CMD_TRIGGER_CODEC_CONNECTION_SETUP },
1140     { "AT+BCS=",   HFP_CMD_HF_CONFIRMED_CODEC },
1141     { "AT+BIA=",   HFP_CMD_ENABLE_INDIVIDUAL_AG_INDICATOR_STATUS_UPDATE, }, // +BIA:<enabled>,,<enabled>,,,<enabled>
1142     { "AT+BIEV=",  HFP_CMD_HF_INDICATOR_STATUS },
1143     { "AT+BIND=",  HFP_CMD_LIST_GENERIC_STATUS_INDICATORS },
1144     { "AT+BIND=?", HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS },
1145     { "AT+BIND?",  HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS_STATE },
1146     { "AT+BINP=",  HFP_CMD_HF_REQUEST_PHONE_NUMBER },
1147     { "AT+BLDN",   HFP_CMD_REDIAL_LAST_NUMBER },
1148     { "AT+BRSF=",  HFP_CMD_SUPPORTED_FEATURES },
1149     { "AT+BTRH=",  HFP_CMD_RESPONSE_AND_HOLD_COMMAND },
1150     { "AT+BTRH?",  HFP_CMD_RESPONSE_AND_HOLD_QUERY },
1151     { "AT+BVRA=",  HFP_CMD_HF_ACTIVATE_VOICE_RECOGNITION },
1152     { "AT+CCWA=",  HFP_CMD_ENABLE_CALL_WAITING_NOTIFICATION},
1153     { "AT+CHLD=",  HFP_CMD_CALL_HOLD },
1154     { "AT+CHLD=?", HFP_CMD_SUPPORT_CALL_HOLD_AND_MULTIPARTY_SERVICES },
1155     { "AT+CHUP",   HFP_CMD_HANG_UP_CALL },
1156     { "AT+CIND=?", HFP_CMD_RETRIEVE_AG_INDICATORS },
1157     { "AT+CIND?",  HFP_CMD_RETRIEVE_AG_INDICATORS_STATUS },
1158     { "AT+CLCC",   HFP_CMD_LIST_CURRENT_CALLS },
1159     { "AT+CLIP=",  HFP_CMD_ENABLE_CLIP},
1160     { "AT+CMEE=",  HFP_CMD_ENABLE_EXTENDED_AUDIO_GATEWAY_ERROR},
1161     { "AT+CMER=",  HFP_CMD_ENABLE_INDICATOR_STATUS_UPDATE },
1162     { "AT+CNUM",   HFP_CMD_GET_SUBSCRIBER_NUMBER_INFORMATION },
1163     { "AT+COPS=",  HFP_CMD_QUERY_OPERATOR_SELECTION_NAME_FORMAT },
1164     { "AT+COPS?",  HFP_CMD_QUERY_OPERATOR_SELECTION_NAME },
1165     { "AT+NREC=",  HFP_CMD_TURN_OFF_EC_AND_NR, },
1166     { "AT+VGM=",   HFP_CMD_SET_MICROPHONE_GAIN },
1167     { "AT+VGS=",   HFP_CMD_SET_SPEAKER_GAIN },
1168     { "AT+VTS=",   HFP_CMD_TRANSMIT_DTMF_CODES },
1169     { "ATA",       HFP_CMD_CALL_ANSWERED },
1170 };
1171 
1172 static hfp_command_entry_t hfp_hf_command_table[] = {
1173     { "+BCS:",  HFP_CMD_AG_SUGGESTED_CODEC },
1174     { "+BIND:", HFP_CMD_SET_GENERIC_STATUS_INDICATOR_STATUS },
1175     { "+BINP:", HFP_CMD_AG_SENT_PHONE_NUMBER },
1176     { "+BRSF:", HFP_CMD_SUPPORTED_FEATURES },
1177     { "+BSIR:", HFP_CMD_CHANGE_IN_BAND_RING_TONE_SETTING },
1178     { "+BTRH:", HFP_CMD_RESPONSE_AND_HOLD_STATUS },
1179     { "+BVRA:", HFP_CMD_AG_ACTIVATE_VOICE_RECOGNITION },
1180     { "+CCWA:", HFP_CMD_AG_SENT_CALL_WAITING_NOTIFICATION_UPDATE, },
1181     { "+CHLD:", HFP_CMD_SUPPORT_CALL_HOLD_AND_MULTIPARTY_SERVICES },
1182     { "+CIEV:", HFP_CMD_TRANSFER_AG_INDICATOR_STATUS},
1183     { "+CIND:", HFP_CMD_RETRIEVE_AG_INDICATORS_GENERIC },
1184     { "+CLCC:", HFP_CMD_LIST_CURRENT_CALLS },
1185     { "+CLIP:", HFP_CMD_AG_SENT_CLIP_INFORMATION },
1186     { "+CME ERROR:", HFP_CMD_EXTENDED_AUDIO_GATEWAY_ERROR },
1187     { "+CNUM:", HFP_CMD_GET_SUBSCRIBER_NUMBER_INFORMATION},
1188     { "+COPS:", HFP_CMD_QUERY_OPERATOR_SELECTION_NAME },
1189     { "+VGM:",  HFP_CMD_SET_MICROPHONE_GAIN },
1190     { "+VGM=",  HFP_CMD_SET_MICROPHONE_GAIN },
1191     { "+VGS:",  HFP_CMD_SET_SPEAKER_GAIN},
1192     { "+VGS=",  HFP_CMD_SET_SPEAKER_GAIN},
1193     { "ERROR",  HFP_CMD_ERROR},
1194     { "NOP",    HFP_CMD_NONE}, // dummy command used by unit tests
1195     { "OK",     HFP_CMD_OK },
1196     { "RING",   HFP_CMD_RING },
1197 };
1198 
1199 static const hfp_custom_at_command_t *
1200 hfp_custom_command_lookup(bool isHandsFree, const char *text) {
1201     btstack_linked_list_t * custom_commands = isHandsFree ? &hfp_custom_commands_hf : &hfp_custom_commands_ag;
1202     btstack_linked_list_iterator_t it;
1203     btstack_linked_list_iterator_init(&it, custom_commands);
1204     while (btstack_linked_list_iterator_has_next(&it)) {
1205         hfp_custom_at_command_t *at_command = (hfp_custom_at_command_t *) btstack_linked_list_iterator_next(&it);
1206         int match = strcmp(text, at_command->command);
1207         if (match == 0) {
1208             return at_command;
1209         }
1210     }
1211     return NULL;
1212 }
1213 
1214 static hfp_command_t parse_command(const char * line_buffer, int isHandsFree){
1215 
1216     // check for custom commands, AG only
1217     const hfp_custom_at_command_t * custom_at_command = hfp_custom_command_lookup(isHandsFree, line_buffer);
1218     if (custom_at_command != NULL){
1219         return HFP_CMD_CUSTOM_MESSAGE;
1220     }
1221 
1222     // table lookup based on role
1223     uint16_t num_entries;
1224     hfp_command_entry_t * table;
1225     if (isHandsFree == 0){
1226         table = hfp_ag_command_table;
1227         num_entries = sizeof(hfp_ag_command_table) / sizeof(hfp_command_entry_t);
1228     } else {
1229         table = hfp_hf_command_table;
1230         num_entries = sizeof(hfp_hf_command_table) / sizeof(hfp_command_entry_t);
1231     }
1232     // binary search
1233     uint16_t left = 0;
1234     uint16_t right = num_entries - 1;
1235     while (left <= right){
1236         uint16_t middle = left + (right - left) / 2;
1237         hfp_command_entry_t *entry = &table[middle];
1238         int match = strcmp(line_buffer, entry->command);
1239         if (match < 0){
1240             // search term is lower than middle element
1241             if (right == 0) break;
1242             right = middle - 1;
1243         } else if (match == 0){
1244             return entry->command_id;
1245         } else {
1246             // search term is higher than middle element
1247             left = middle + 1;
1248         }
1249     }
1250 
1251     // note: if parser in CMD_HEADER state would treats digits and maybe '+' as separator, match on "ATD" would work.
1252     // note: phone number is currently expected in line_buffer[3..]
1253     // prefix match on 'ATD', AG only
1254     if ((isHandsFree == 0) && (strncmp(line_buffer, HFP_CALL_PHONE_NUMBER, strlen(HFP_CALL_PHONE_NUMBER)) == 0)){
1255         return HFP_CMD_CALL_PHONE_NUMBER;
1256     }
1257 
1258     // Valid looking, but unknown commands/responses
1259     if ((isHandsFree == 0) && (strncmp(line_buffer, "AT+", 3) == 0)){
1260         return HFP_CMD_UNKNOWN;
1261     }
1262 
1263     if ((isHandsFree != 0) && (strncmp(line_buffer, "+", 1) == 0)){
1264         return HFP_CMD_UNKNOWN;
1265     }
1266 
1267     return HFP_CMD_NONE;
1268 }
1269 
1270 static void hfp_parser_store_byte(hfp_connection_t * hfp_connection, uint8_t byte){
1271     if ((hfp_connection->line_size + 1) >= HFP_MAX_VR_TEXT_SIZE) return;
1272     hfp_connection->line_buffer[hfp_connection->line_size++] = byte;
1273     hfp_connection->line_buffer[hfp_connection->line_size] = 0;
1274 }
1275 static int hfp_parser_is_buffer_empty(hfp_connection_t * hfp_connection){
1276     return hfp_connection->line_size == 0;
1277 }
1278 
1279 static int hfp_parser_is_end_of_line(uint8_t byte){
1280     return (byte == '\n') || (byte == '\r');
1281 }
1282 
1283 void hfp_parser_reset_line_buffer(hfp_connection_t *hfp_connection) {
1284     hfp_connection->line_size = 0;
1285     // we don't set the first byte to '\0' to allow access to last argument e.g. in hfp_hf_handle_rfcommand
1286 }
1287 
1288 static void hfp_parser_store_if_token(hfp_connection_t * hfp_connection, uint8_t byte){
1289     switch (byte){
1290         case ',':
1291 		case '-':
1292         case ';':
1293         case '(':
1294         case ')':
1295         case '\n':
1296         case '\r':
1297             break;
1298         default:
1299             hfp_parser_store_byte(hfp_connection, byte);
1300             break;
1301     }
1302 }
1303 
1304 static bool hfp_parser_is_separator( uint8_t byte){
1305     switch (byte){
1306         case ',':
1307 		case '-':
1308         case ';':
1309         case '\n':
1310         case '\r':
1311             return true;
1312         default:
1313             return false;
1314     }
1315 }
1316 
1317 // returns true if received bytes was processed. Otherwise, functions will be called with same byte again
1318 // this is used to for a one byte lookahead, where an unexpected byte is pushed back by returning false
1319 static bool hfp_parse_byte(hfp_connection_t * hfp_connection, uint8_t byte, int isHandsFree){
1320 
1321 #ifdef HFP_DEBUG
1322     if (byte >= ' '){
1323         printf("Parse  '%c' - state %u, buffer %s\n", byte, hfp_connection->parser_state, hfp_connection->line_buffer);
1324     } else {
1325         printf("Parse 0x%02x - state %u, buffer %s\n", byte, hfp_connection->parser_state, hfp_connection->line_buffer);
1326     }
1327 #endif
1328 
1329     // handle doubles quotes
1330     if (byte == '"'){
1331         hfp_connection->parser_quoted = !hfp_connection->parser_quoted;
1332         return true;
1333     }
1334     if (hfp_connection->parser_quoted) {
1335         hfp_parser_store_byte(hfp_connection, byte);
1336         return true;
1337     }
1338 
1339     // ignore spaces outside command or double quotes (required e.g. for '+CME ERROR:..") command
1340     if ((byte == ' ') && (hfp_connection->parser_state != HFP_PARSER_CMD_HEADER)) return true;
1341 
1342     bool processed = true;
1343 
1344     switch (hfp_connection->parser_state) {
1345         case HFP_PARSER_CMD_HEADER:
1346             switch (byte) {
1347                 case '\n':
1348                 case '\r':
1349                 case ';':
1350                     // ignore separator
1351                     break;
1352                 case ':':
1353                 case '?':
1354                     // store separator
1355                     hfp_parser_store_byte(hfp_connection, byte);
1356                     break;
1357                 case '=':
1358                     // equal sign: remember and wait for next char to decided between '=?' and '=\?'
1359                     hfp_connection->found_equal_sign = true;
1360                     hfp_parser_store_byte(hfp_connection, byte);
1361                     return true;
1362                 default:
1363                     // store if not lookahead
1364                     if (!hfp_connection->found_equal_sign) {
1365                         hfp_parser_store_byte(hfp_connection, byte);
1366                         return true;
1367                     }
1368                     // mark as lookahead
1369                     processed = false;
1370                     break;
1371             }
1372 
1373             // ignore empty tokens
1374             if (hfp_parser_is_buffer_empty(hfp_connection)) return true;
1375 
1376             // parse
1377             hfp_connection->command = parse_command((char *)hfp_connection->line_buffer, isHandsFree);
1378 
1379             // pick +CIND version based on connection state: descriptions during SLC vs. states later
1380             if (hfp_connection->command == HFP_CMD_RETRIEVE_AG_INDICATORS_GENERIC){
1381                 switch(hfp_connection->state){
1382                     case HFP_W4_RETRIEVE_INDICATORS_STATUS:
1383                         hfp_connection->command = HFP_CMD_RETRIEVE_AG_INDICATORS_STATUS;
1384                         break;
1385                     case HFP_W4_RETRIEVE_INDICATORS:
1386                         hfp_connection->command = HFP_CMD_RETRIEVE_AG_INDICATORS;
1387                         break;
1388                     default:
1389                         hfp_connection->command = HFP_CMD_UNKNOWN;
1390                         break;
1391                 }
1392             }
1393 
1394             log_info("command string '%s', handsfree %u -> cmd id %u", (char *)hfp_connection->line_buffer, isHandsFree, hfp_connection->command);
1395 
1396             // store command id for custom command and just store rest of line
1397             if (hfp_connection->command == HFP_CMD_CUSTOM_MESSAGE){
1398                 const hfp_custom_at_command_t * at_command = hfp_custom_command_lookup(isHandsFree, (const char *) hfp_connection->line_buffer);
1399                 hfp_connection->custom_at_command_id = at_command->command_id;
1400                 hfp_connection->parser_state = HFP_PARSER_CUSTOM_COMMAND;
1401                 return processed;
1402             }
1403 
1404             // next state
1405             hfp_parser_reset_line_buffer(hfp_connection);
1406             hfp_connection->parser_state = HFP_PARSER_CMD_SEQUENCE;
1407 
1408             return processed;
1409 
1410         case HFP_PARSER_CMD_SEQUENCE:
1411             // handle empty fields
1412             if ((byte == ',' ) && (hfp_connection->line_size == 0)){
1413                 hfp_connection->line_buffer[0] = 0;
1414                 hfp_connection->ignore_value = 1;
1415                 parse_sequence(hfp_connection);
1416                 return true;
1417             }
1418 
1419             hfp_parser_store_if_token(hfp_connection, byte);
1420             if (!hfp_parser_is_separator(byte)) return true;
1421 
1422             // ignore empty tokens
1423             switch (hfp_connection->command){
1424                 case HFP_CMD_AG_ACTIVATE_VOICE_RECOGNITION:
1425                     // don't ignore empty string
1426                     break;
1427                 default:
1428                     if (hfp_parser_is_buffer_empty(hfp_connection) && (hfp_connection->ignore_value == 0)) {
1429                         return true;
1430                     }
1431                     break;
1432             }
1433 
1434             parse_sequence(hfp_connection);
1435 
1436             hfp_parser_reset_line_buffer(hfp_connection);
1437 
1438             switch (hfp_connection->command){
1439                 case HFP_CMD_AG_SENT_PHONE_NUMBER:
1440                 case HFP_CMD_AG_SENT_CALL_WAITING_NOTIFICATION_UPDATE:
1441                 case HFP_CMD_AG_SENT_CLIP_INFORMATION:
1442                 case HFP_CMD_TRANSFER_AG_INDICATOR_STATUS:
1443                 case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME:
1444                 case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME_FORMAT:
1445                 case HFP_CMD_RETRIEVE_AG_INDICATORS:
1446                 case HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS_STATE:
1447                 case HFP_CMD_HF_INDICATOR_STATUS:
1448                     hfp_connection->parser_state = HFP_PARSER_SECOND_ITEM;
1449                     break;
1450                 default:
1451                     break;
1452             }
1453             return true;
1454 
1455         case HFP_PARSER_SECOND_ITEM:
1456 
1457             hfp_parser_store_if_token(hfp_connection, byte);
1458             if (!hfp_parser_is_separator(byte)) return true;
1459 
1460             switch (hfp_connection->command){
1461                 case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME:
1462                     log_info("format %s, ", hfp_connection->line_buffer);
1463                     hfp_connection->network_operator.format =  btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1464                     break;
1465                 case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME_FORMAT:
1466                     log_info("format %s \n", hfp_connection->line_buffer);
1467                     hfp_connection->network_operator.format =  btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1468                     break;
1469                 case HFP_CMD_LIST_GENERIC_STATUS_INDICATORS:
1470                 case HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS:
1471                 case HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS_STATE:
1472                     hfp_connection->generic_status_indicators[hfp_connection->parser_item_index].state = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1473                     break;
1474                 case HFP_CMD_TRANSFER_AG_INDICATOR_STATUS:
1475                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].status = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1476                     log_info("%d \n", hfp_connection->ag_indicators[hfp_connection->parser_item_index].status);
1477                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].status_changed = 1;
1478                     break;
1479                 case HFP_CMD_RETRIEVE_AG_INDICATORS:
1480                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].min_range = btstack_atoi((char *)hfp_connection->line_buffer);
1481                     log_info("%s, ", hfp_connection->line_buffer);
1482                     break;
1483                 case HFP_CMD_AG_SENT_PHONE_NUMBER:
1484                 case HFP_CMD_AG_SENT_CALL_WAITING_NOTIFICATION_UPDATE:
1485                 case HFP_CMD_AG_SENT_CLIP_INFORMATION:
1486                     hfp_connection->bnip_type = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1487                     break;
1488                 case HFP_CMD_HF_INDICATOR_STATUS:
1489                     hfp_connection->parser_indicator_value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1490                     break;
1491                 default:
1492                     break;
1493             }
1494 
1495             hfp_parser_reset_line_buffer(hfp_connection);
1496 
1497             hfp_connection->parser_state = HFP_PARSER_THIRD_ITEM;
1498 
1499             return true;
1500 
1501         case HFP_PARSER_THIRD_ITEM:
1502 
1503             hfp_parser_store_if_token(hfp_connection, byte);
1504             if (!hfp_parser_is_separator(byte)) return true;
1505 
1506             switch (hfp_connection->command){
1507                 case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME:
1508                     btstack_strcpy(hfp_connection->network_operator.name, HFP_MAX_NETWORK_OPERATOR_NAME_SIZE,  (char *)hfp_connection->line_buffer);
1509                     break;
1510                 case HFP_CMD_RETRIEVE_AG_INDICATORS:
1511                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].max_range = btstack_atoi((char *)hfp_connection->line_buffer);
1512                     hfp_next_indicators_index(hfp_connection);
1513                     hfp_connection->ag_indicators_nr = hfp_connection->parser_item_index;
1514                     break;
1515                 case HFP_CMD_AG_SENT_CLIP_INFORMATION:
1516                 case HFP_CMD_AG_SENT_CALL_WAITING_NOTIFICATION_UPDATE:
1517                     // track if last argument exists
1518                     hfp_connection->clip_have_alpha = hfp_connection->line_size != 0;
1519                     break;
1520                 default:
1521                     break;
1522             }
1523 
1524             hfp_parser_reset_line_buffer(hfp_connection);
1525 
1526             if (hfp_connection->command == HFP_CMD_RETRIEVE_AG_INDICATORS){
1527                 hfp_connection->parser_state = HFP_PARSER_CMD_SEQUENCE;
1528             }
1529             return true;
1530 
1531         case HFP_PARSER_CUSTOM_COMMAND:
1532             if (hfp_parser_is_end_of_line(byte) == false){
1533                 hfp_parser_store_byte(hfp_connection, byte);
1534             }
1535             return true;
1536 
1537         default:
1538             btstack_assert(false);
1539             return true;
1540     }
1541 }
1542 
1543 void hfp_parse(hfp_connection_t * hfp_connection, uint8_t byte, int isHandsFree){
1544     bool processed = false;
1545     while (!processed){
1546         processed = hfp_parse_byte(hfp_connection, byte, isHandsFree);
1547     }
1548     // reset parser state on end-of-line
1549     if (hfp_parser_is_end_of_line(byte)){
1550         hfp_connection->found_equal_sign = false;
1551         hfp_connection->parser_item_index = 0;
1552         hfp_connection->parser_state = HFP_PARSER_CMD_HEADER;
1553     }
1554 }
1555 
1556 static void parse_sequence(hfp_connection_t * hfp_connection){
1557     int value;
1558     switch (hfp_connection->command){
1559         case HFP_CMD_SET_GENERIC_STATUS_INDICATOR_STATUS:
1560             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1561             int i;
1562             switch (hfp_connection->parser_item_index){
1563                 case 0:
1564                     for (i=0;i<hfp_connection->generic_status_indicators_nr;i++){
1565                         if (hfp_connection->generic_status_indicators[i].uuid == value){
1566                             hfp_connection->parser_indicator_index = i;
1567                             break;
1568                         }
1569                     }
1570                     break;
1571                 case 1:
1572                     if (hfp_connection->parser_indicator_index <0) break;
1573                     hfp_connection->generic_status_indicators[hfp_connection->parser_indicator_index].state = value;
1574                     log_info("HFP_CMD_SET_GENERIC_STATUS_INDICATOR_STATUS set indicator at index %u, to %u\n",
1575                      hfp_connection->parser_item_index, value);
1576                     break;
1577                 default:
1578                     break;
1579             }
1580             hfp_next_indicators_index(hfp_connection);
1581             break;
1582 
1583         case HFP_CMD_GET_SUBSCRIBER_NUMBER_INFORMATION:
1584             switch(hfp_connection->parser_item_index){
1585                 case 0:
1586                     // <alpha>: This optional field is not supported, and shall be left blank.
1587                     break;
1588                 case 1:
1589                     // <number>: Quoted string containing the phone number in the format specified by <type>.
1590                     btstack_strcpy(hfp_connection->bnip_number, sizeof(hfp_connection->bnip_number), (char *)hfp_connection->line_buffer);
1591                     break;
1592                 case 2:
1593                     /*
1594                       <type> field specifies the format of the phone number provided, and can be one of the following values:
1595                       - values 128-143: The phone number format may be a national or international format, and may contain prefix and/or escape digits. No changes on the number presentation are required.
1596                      - values 144-159: The phone number format is an international number, including the country code prefix. If the plus sign ("+") is not included as part of the number and shall be added by the AG as needed.
1597                      - values 160-175: National number. No prefix nor escape digits included.
1598                      */
1599                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1600                     hfp_connection->bnip_type = value;
1601                     break;
1602                 case 3:
1603                     // <speed>: This optional field is not supported, and shall be left blank.
1604                     break;
1605                 case 4:
1606                     // <service>: Indicates which service this phone number relates to. Shall be either 4 (voice) or 5 (fax).
1607                 default:
1608                     break;
1609             }
1610             // index > 2 are ignored in switch above
1611             hfp_connection->parser_item_index++;
1612             break;
1613         case HFP_CMD_LIST_CURRENT_CALLS:
1614             switch(hfp_connection->parser_item_index){
1615                 case 0:
1616                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1617                     hfp_connection->clcc_idx = value;
1618                     break;
1619                 case 1:
1620                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1621                     hfp_connection->clcc_dir = value;
1622                     break;
1623                 case 2:
1624                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1625                     hfp_connection->clcc_status = value;
1626                     break;
1627                 case 3:
1628                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1629                     hfp_connection->clcc_mode = value;
1630                     break;
1631                 case 4:
1632                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1633                     hfp_connection->clcc_mpty = value;
1634                     break;
1635                 case 5:
1636                     btstack_strcpy(hfp_connection->bnip_number, sizeof(hfp_connection->bnip_number), (char *)hfp_connection->line_buffer);
1637                     break;
1638                 case 6:
1639                     value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1640                     hfp_connection->bnip_type = value;
1641                     break;
1642                 default:
1643                     break;
1644             }
1645             // index > 6 are ignored in switch above
1646             hfp_connection->parser_item_index++;
1647             break;
1648         case HFP_CMD_SET_MICROPHONE_GAIN:
1649             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1650             hfp_connection->microphone_gain = value;
1651             log_info("hfp parse HFP_CMD_SET_MICROPHONE_GAIN %d\n", value);
1652             break;
1653         case HFP_CMD_SET_SPEAKER_GAIN:
1654             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1655             hfp_connection->speaker_gain = value;
1656             log_info("hfp parse HFP_CMD_SET_SPEAKER_GAIN %d\n", value);
1657             break;
1658         case HFP_CMD_TURN_OFF_EC_AND_NR:
1659             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1660             hfp_connection->ag_echo_and_noise_reduction = value;
1661             log_info("hfp parse HFP_CMD_TURN_OFF_EC_AND_NR %d\n", value);
1662             break;
1663         case HFP_CMD_CHANGE_IN_BAND_RING_TONE_SETTING:
1664             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1665             hfp_connection->remote_supported_features = store_bit(hfp_connection->remote_supported_features, HFP_AGSF_IN_BAND_RING_TONE, value);
1666             log_info("hfp parse HFP_CHANGE_IN_BAND_RING_TONE_SETTING %d\n", value);
1667             break;
1668         case HFP_CMD_HF_CONFIRMED_CODEC:
1669             hfp_connection->codec_confirmed = btstack_atoi((char*)hfp_connection->line_buffer);
1670             log_info("hfp parse HFP_CMD_HF_CONFIRMED_CODEC %d\n", hfp_connection->codec_confirmed);
1671             break;
1672         case HFP_CMD_AG_SUGGESTED_CODEC:
1673             hfp_connection->suggested_codec = btstack_atoi((char*)hfp_connection->line_buffer);
1674             log_info("hfp parse HFP_CMD_AG_SUGGESTED_CODEC %d\n", hfp_connection->suggested_codec);
1675             break;
1676         case HFP_CMD_SUPPORTED_FEATURES:
1677             hfp_connection->remote_supported_features = btstack_atoi((char*)hfp_connection->line_buffer);
1678             log_info("Parsed supported feature %d\n", (int) hfp_connection->remote_supported_features);
1679             break;
1680         case HFP_CMD_AVAILABLE_CODECS:
1681             log_info("Parsed codec %s\n", hfp_connection->line_buffer);
1682             hfp_connection->remote_codecs[hfp_connection->parser_item_index] = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1683             hfp_next_codec_index(hfp_connection);
1684             hfp_connection->remote_codecs_nr = hfp_connection->parser_item_index;
1685             break;
1686         case HFP_CMD_RETRIEVE_AG_INDICATORS:
1687             btstack_strcpy((char *)hfp_connection->ag_indicators[hfp_connection->parser_item_index].name, HFP_MAX_INDICATOR_DESC_SIZE, (char *)hfp_connection->line_buffer);
1688             hfp_connection->ag_indicators[hfp_connection->parser_item_index].index = hfp_connection->parser_item_index+1;
1689             log_info("Indicator %d: %s (", hfp_connection->ag_indicators_nr+1, hfp_connection->line_buffer);
1690             break;
1691         case HFP_CMD_RETRIEVE_AG_INDICATORS_STATUS:
1692             log_info("Parsed Indicator %d with status: %s\n", hfp_connection->parser_item_index+1, hfp_connection->line_buffer);
1693             hfp_connection->ag_indicators[hfp_connection->parser_item_index].status = btstack_atoi((char *) hfp_connection->line_buffer);
1694             hfp_next_indicators_index(hfp_connection);
1695             break;
1696         case HFP_CMD_ENABLE_INDICATOR_STATUS_UPDATE:
1697             hfp_next_indicators_index(hfp_connection);
1698             if (hfp_connection->parser_item_index != 4) break;
1699             log_info("Parsed Enable indicators: %s\n", hfp_connection->line_buffer);
1700             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1701             hfp_connection->enable_status_update_for_ag_indicators = (uint8_t) value;
1702             break;
1703         case HFP_CMD_SUPPORT_CALL_HOLD_AND_MULTIPARTY_SERVICES:
1704             log_info("Parsed Support call hold: %s\n", hfp_connection->line_buffer);
1705             if (hfp_connection->line_size > 2 ) break;
1706             memcpy((char *)hfp_connection->remote_call_services[hfp_connection->remote_call_services_index].name, (char *)hfp_connection->line_buffer, HFP_CALL_SERVICE_SIZE-1);
1707             hfp_connection->remote_call_services[hfp_connection->remote_call_services_index].name[HFP_CALL_SERVICE_SIZE - 1] = 0;
1708             hfp_next_remote_call_services_index(hfp_connection);
1709             break;
1710         case HFP_CMD_LIST_GENERIC_STATUS_INDICATORS:
1711         case HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS:
1712             log_info("Parsed Generic status indicator: %s\n", hfp_connection->line_buffer);
1713             hfp_connection->generic_status_indicators[hfp_connection->parser_item_index].uuid = (uint16_t)btstack_atoi((char*)hfp_connection->line_buffer);
1714             hfp_next_indicators_index(hfp_connection);
1715             hfp_connection->generic_status_indicators_nr = hfp_connection->parser_item_index;
1716             break;
1717         case HFP_CMD_RETRIEVE_GENERIC_STATUS_INDICATORS_STATE:
1718             // HF parses inital AG gen. ind. state
1719             log_info("Parsed List generic status indicator %s state: ", hfp_connection->line_buffer);
1720             hfp_connection->parser_item_index = hfp_parse_indicator_index(hfp_connection);
1721             break;
1722         case HFP_CMD_HF_INDICATOR_STATUS:
1723             hfp_connection->parser_indicator_index = hfp_parse_indicator_index(hfp_connection);
1724             log_info("Parsed HF indicator index %u", hfp_connection->parser_indicator_index);
1725             break;
1726         case HFP_CMD_ENABLE_INDIVIDUAL_AG_INDICATOR_STATUS_UPDATE:
1727             // AG parses new gen. ind. state
1728             if (hfp_connection->ignore_value){
1729                 hfp_connection->ignore_value = 0;
1730                 log_info("Parsed Enable AG indicator pos %u('%s') - unchanged (stays %u)\n", hfp_connection->parser_item_index,
1731                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].name, hfp_connection->ag_indicators[hfp_connection->parser_item_index].enabled);
1732             }
1733             else if (hfp_connection->ag_indicators[hfp_connection->parser_item_index].mandatory){
1734                 log_info("Parsed Enable AG indicator pos %u('%s') - ignore (mandatory)\n",
1735                     hfp_connection->parser_item_index, hfp_connection->ag_indicators[hfp_connection->parser_item_index].name);
1736             } else {
1737                 value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1738                 hfp_connection->ag_indicators[hfp_connection->parser_item_index].enabled = value;
1739                 log_info("Parsed Enable AG indicator pos %u('%s'): %u\n", hfp_connection->parser_item_index,
1740                     hfp_connection->ag_indicators[hfp_connection->parser_item_index].name, value);
1741             }
1742             hfp_next_indicators_index(hfp_connection);
1743             break;
1744         case HFP_CMD_TRANSFER_AG_INDICATOR_STATUS:
1745             // indicators are indexed starting with 1
1746             hfp_connection->parser_item_index = hfp_parse_indicator_index(hfp_connection);
1747             log_info("Parsed status of the AG indicator %d, status ", hfp_connection->parser_item_index);
1748             break;
1749         case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME:
1750             hfp_connection->network_operator.mode = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1751             log_info("Parsed network operator mode: %d, ", hfp_connection->network_operator.mode);
1752             break;
1753         case HFP_CMD_QUERY_OPERATOR_SELECTION_NAME_FORMAT:
1754             if (hfp_connection->line_buffer[0] == '3'){
1755                 log_info("Parsed Set network operator format : %s, ", hfp_connection->line_buffer);
1756                 break;
1757             }
1758             // TODO emit ERROR, wrong format
1759             log_info("ERROR Set network operator format: index %s not supported\n", hfp_connection->line_buffer);
1760             break;
1761         case HFP_CMD_ERROR:
1762             break;
1763         case HFP_CMD_EXTENDED_AUDIO_GATEWAY_ERROR:
1764             hfp_connection->extended_audio_gateway_error = 1;
1765             hfp_connection->extended_audio_gateway_error_value = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1766             break;
1767         case HFP_CMD_ENABLE_EXTENDED_AUDIO_GATEWAY_ERROR:
1768             hfp_connection->enable_extended_audio_gateway_error_report = (uint8_t)btstack_atoi((char*)hfp_connection->line_buffer);
1769             hfp_connection->ok_pending = 1;
1770             hfp_connection->extended_audio_gateway_error = 0;
1771             break;
1772         case HFP_CMD_AG_SENT_PHONE_NUMBER:
1773         case HFP_CMD_AG_SENT_CALL_WAITING_NOTIFICATION_UPDATE:
1774         case HFP_CMD_AG_SENT_CLIP_INFORMATION:
1775             btstack_strcpy((char *)hfp_connection->bnip_number, sizeof(hfp_connection->bnip_number), (char *)hfp_connection->line_buffer);
1776             break;
1777         case HFP_CMD_CALL_HOLD:
1778             hfp_connection->ag_call_hold_action = hfp_connection->line_buffer[0] - '0';
1779             if (hfp_connection->line_buffer[1] != '\0'){
1780                 hfp_connection->call_index = btstack_atoi((char *)&hfp_connection->line_buffer[1]);
1781             }
1782             break;
1783         case HFP_CMD_RESPONSE_AND_HOLD_COMMAND:
1784             hfp_connection->ag_response_and_hold_action = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1785             break;
1786         case HFP_CMD_TRANSMIT_DTMF_CODES:
1787             hfp_connection->ag_dtmf_code = hfp_connection->line_buffer[0];
1788             break;
1789         case HFP_CMD_ENABLE_CLIP:
1790             hfp_connection->clip_enabled = hfp_connection->line_buffer[0] != '0';
1791             break;
1792         case HFP_CMD_ENABLE_CALL_WAITING_NOTIFICATION:
1793             hfp_connection->call_waiting_notification_enabled = hfp_connection->line_buffer[0] != '0';
1794             break;
1795         case HFP_CMD_HF_ACTIVATE_VOICE_RECOGNITION:
1796             value = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1797             hfp_connection->ag_activate_voice_recognition_value = value;
1798             break;
1799         case HFP_CMD_AG_ACTIVATE_VOICE_RECOGNITION:
1800             switch(hfp_connection->parser_item_index){
1801                 case 0:
1802                     hfp_connection->ag_vra_status = btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1803                     break;
1804                 case 1:
1805                     hfp_connection->ag_vra_state = (hfp_voice_recognition_state_t) btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1806                     break;
1807                 case 2:
1808                     hfp_connection->ag_msg.text_id = 0;
1809                     for (i = 0 ; i < 4; i++){
1810                         hfp_connection->ag_msg.text_id = (hfp_connection->ag_msg.text_id << 4) | nibble_for_char(hfp_connection->line_buffer[i]);
1811                     }
1812                     break;
1813                 case 3:
1814                     hfp_connection->ag_msg.text_type = (hfp_text_type_t) btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1815                     break;
1816                 case 4:
1817                     hfp_connection->ag_msg.text_operation = (hfp_text_operation_t) btstack_atoi((char *)&hfp_connection->line_buffer[0]);
1818                     break;
1819                 case 5:
1820                     hfp_connection->line_buffer[hfp_connection->line_size] = 0;
1821                     hfp_connection->ag_vra_msg_length = hfp_connection->line_size + 1;
1822                     break;
1823                 default:
1824                     break;
1825             }
1826             hfp_connection->parser_item_index++;
1827             break;
1828         default:
1829             break;
1830     }
1831 }
1832 
1833 static void hfp_handle_start_sdp_client_query(void * context){
1834     UNUSED(context);
1835 
1836     btstack_linked_list_iterator_t it;
1837     btstack_linked_list_iterator_init(&it, &hfp_connections);
1838     while (btstack_linked_list_iterator_has_next(&it)){
1839         hfp_connection_t * connection = (hfp_connection_t *)btstack_linked_list_iterator_next(&it);
1840 
1841         if (connection->state != HFP_W2_SEND_SDP_QUERY) continue;
1842 
1843         connection->state = HFP_W4_SDP_QUERY_COMPLETE;
1844         hfp_sdp_query_context.local_role = connection->local_role;
1845         (void)memcpy(hfp_sdp_query_context.remote_address, connection->remote_addr, 6);
1846         sdp_client_query_rfcomm_channel_and_name_for_service_class_uuid(&handle_query_rfcomm_event, connection->remote_addr, connection->service_uuid);
1847         return;
1848     }
1849 }
1850 
1851 uint8_t hfp_establish_service_level_connection(bd_addr_t bd_addr, uint16_t service_uuid, hfp_role_t local_role){
1852     hfp_connection_t * connection = get_hfp_connection_context_for_bd_addr(bd_addr, local_role);
1853     if (connection){
1854         return ERROR_CODE_COMMAND_DISALLOWED;
1855     }
1856 
1857     connection = hfp_create_connection(bd_addr, local_role);
1858     if (!connection){
1859         return BTSTACK_MEMORY_ALLOC_FAILED;
1860     }
1861 
1862     connection->state = HFP_W2_SEND_SDP_QUERY;
1863 
1864     bd_addr_copy(connection->remote_addr, bd_addr);
1865     connection->service_uuid = service_uuid;
1866 
1867     hfp_sdp_query_request.callback = &hfp_handle_start_sdp_client_query;
1868     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
1869     (void) sdp_client_register_query_callback(&hfp_sdp_query_request);
1870     return ERROR_CODE_SUCCESS;
1871 }
1872 
1873 void hfp_trigger_release_service_level_connection(hfp_connection_t * hfp_connection){
1874     // called internally, NULL check already performed
1875     btstack_assert(hfp_connection != NULL);
1876 
1877     hfp_trigger_release_audio_connection(hfp_connection);
1878     if (hfp_connection->state < HFP_W4_RFCOMM_CONNECTED){
1879         hfp_connection->state = HFP_IDLE;
1880         return;
1881     }
1882 
1883     if (hfp_connection->state == HFP_W4_RFCOMM_CONNECTED){
1884         hfp_connection->state = HFP_W4_CONNECTION_ESTABLISHED_TO_SHUTDOWN;
1885         return;
1886     }
1887     hfp_connection->release_slc_connection = 1;
1888     if (hfp_connection->state < HFP_W4_SCO_CONNECTED){
1889         hfp_connection->state = HFP_W2_DISCONNECT_RFCOMM;
1890         return;
1891     }
1892 
1893     if (hfp_connection->state < HFP_W4_SCO_DISCONNECTED){
1894         hfp_connection->state = HFP_W2_DISCONNECT_SCO;
1895         hfp_connection->release_audio_connection = 1;
1896         return;
1897     }
1898 }
1899 
1900 uint8_t hfp_trigger_release_audio_connection(hfp_connection_t * hfp_connection){
1901     // called internally, NULL check already performed
1902     btstack_assert(hfp_connection != NULL);
1903     if (hfp_connection->state <= HFP_SERVICE_LEVEL_CONNECTION_ESTABLISHED){
1904         return ERROR_CODE_COMMAND_DISALLOWED;
1905     }
1906     switch (hfp_connection->state) {
1907         case HFP_W2_CONNECT_SCO:
1908             hfp_connection->state = HFP_SERVICE_LEVEL_CONNECTION_ESTABLISHED;
1909             break;
1910         case HFP_W4_SCO_CONNECTED:
1911         case HFP_AUDIO_CONNECTION_ESTABLISHED:
1912             hfp_connection->release_audio_connection = 1;
1913             break;
1914         default:
1915             return ERROR_CODE_COMMAND_DISALLOWED;
1916     }
1917     return ERROR_CODE_SUCCESS;
1918 }
1919 
1920 void hfp_setup_synchronous_connection(hfp_connection_t * hfp_connection){
1921     // all packet types, fixed bandwidth
1922     int setting = hfp_connection->link_setting;
1923     log_info("hfp_setup_synchronous_connection using setting nr %u", setting);
1924     hfp_sco_establishment_active = hfp_connection;
1925     uint16_t sco_voice_setting = hci_get_sco_voice_setting();
1926     if (hfp_connection->negotiated_codec != HFP_CODEC_CVSD){
1927 #ifdef ENABLE_BCM_PCM_WBS
1928         sco_voice_setting = 0x0063; // Transparent data, 16-bit for BCM controllers
1929 #else
1930         sco_voice_setting = 0x0043; // Transparent data, 8-bit otherwise
1931 #endif
1932     }
1933     uint16_t packet_types = hfp_link_settings[setting].packet_types;
1934     hfp_connection->packet_types = packet_types;
1935 
1936     // get packet types - bits 6-9 are 'don't allow'
1937     uint16_t packet_types_flipped = packet_types ^ 0x03c0;
1938     hci_send_cmd(&hci_setup_synchronous_connection, hfp_connection->acl_handle, 8000, 8000, hfp_link_settings[setting].max_latency,
1939         sco_voice_setting, hfp_link_settings[setting].retransmission_effort, packet_types_flipped);
1940 }
1941 
1942 hfp_link_settings_t hfp_safe_settings_for_context(bool use_eSCO, uint8_t negotiated_codec, bool secure_connection_in_use){
1943     uint8_t i;
1944     hfp_link_settings_t link_setting = HFP_LINK_SETTINGS_NONE;
1945     for (i=0 ; i < ( sizeof(hfp_mandatory_safe_settings) / sizeof(struct hfp_mandatory_safe_setting) ) ; i++){
1946         if (hfp_link_settings[(uint8_t)(hfp_mandatory_safe_settings[i].link_setting)].eSCO != use_eSCO) continue;
1947         if ((hfp_mandatory_safe_settings[i].codec_mask & (1 << negotiated_codec)) == 0) continue;
1948         if (hfp_mandatory_safe_settings[i].secure_connection_in_use != secure_connection_in_use) continue;
1949         link_setting = hfp_mandatory_safe_settings[i].link_setting;
1950         break;
1951     }
1952     return link_setting;
1953 }
1954 
1955 void hfp_accept_synchronous_connection(hfp_connection_t * hfp_connection, bool use_eSCO){
1956 
1957     bool secure_connection_in_use = gap_secure_connection(hfp_connection->acl_handle);
1958 
1959     // lookup safe settings based on SCO type, SC use and Codec type
1960     hfp_link_settings_t link_setting = hfp_safe_settings_for_context(use_eSCO, hfp_connection->negotiated_codec, secure_connection_in_use);
1961     btstack_assert(link_setting != HFP_LINK_SETTINGS_NONE);
1962 
1963     uint16_t max_latency = hfp_link_settings[(uint8_t) link_setting].max_latency;
1964     uint16_t retransmission_effort = hfp_link_settings[(uint8_t) link_setting].retransmission_effort;
1965 
1966     // safer to allow more packet types:
1967     uint16_t packet_types = use_eSCO ? (SCO_PACKET_TYPES_EV3 | SCO_PACKET_TYPES_2EV3) : (SCO_PACKET_TYPES_HV1 | SCO_PACKET_TYPES_HV3);
1968 
1969     // transparent data for non-CVSD connections or if codec provided by Controller
1970     uint16_t sco_voice_setting = hci_get_sco_voice_setting();
1971     if (hfp_connection->negotiated_codec != HFP_CODEC_CVSD){
1972 #ifdef ENABLE_BCM_PCM_WBS
1973         sco_voice_setting = 0x0063; // Transparent data, 16-bit for BCM controllers
1974 #else
1975         sco_voice_setting = 0x0043; // Transparent data, 8-bit otherwise
1976 #endif
1977     }
1978 
1979     // filter packet types
1980     packet_types &= hfp_get_sco_packet_types();
1981 
1982     hfp_connection->packet_types = packet_types;
1983 
1984     // bits 6-9 are 'don't allow'
1985     uint16_t packet_types_flipped = packet_types ^ 0x3c0;
1986 
1987     log_info("HFP: sending hci_accept_connection_request, packet types 0x%04x, sco_voice_setting 0x%02x", packet_types, sco_voice_setting);
1988     hci_send_cmd(&hci_accept_synchronous_connection, hfp_connection->remote_addr, 8000, 8000, max_latency,
1989                  sco_voice_setting, retransmission_effort, packet_types_flipped);
1990 }
1991 
1992 #ifdef ENABLE_CC256X_ASSISTED_HFP
1993 void hfp_cc256x_prepare_for_sco(hfp_connection_t * hfp_connection){
1994     hfp_connection->cc256x_send_write_codec_config = true;
1995     if (hfp_connection->negotiated_codec == HFP_CODEC_MSBC){
1996         hfp_connection->cc256x_send_wbs_associate = true;
1997     }
1998 }
1999 
2000 void hfp_cc256x_write_codec_config(hfp_connection_t * hfp_connection){
2001     uint32_t sample_rate_hz;
2002     uint16_t clock_rate_khz;
2003     if (hfp_connection->negotiated_codec == HFP_CODEC_MSBC){
2004         clock_rate_khz = 512;
2005         sample_rate_hz = 16000;
2006     } else {
2007         clock_rate_khz = 256;
2008         sample_rate_hz = 8000;
2009     }
2010     uint8_t clock_direction = 0;        // master
2011     uint16_t frame_sync_duty_cycle = 0; // i2s with 50%
2012     uint8_t  frame_sync_edge = 1;       // rising edge
2013     uint8_t  frame_sync_polarity = 0;   // active high
2014     uint8_t  reserved = 0;
2015     uint16_t size = 16;
2016     uint16_t chan_1_offset = 1;
2017     uint16_t chan_2_offset = chan_1_offset + size;
2018     uint8_t  out_edge = 1;              // rising
2019     uint8_t  in_edge = 0;               // falling
2020     hci_send_cmd(&hci_ti_write_codec_config, clock_rate_khz, clock_direction, sample_rate_hz, frame_sync_duty_cycle,
2021                  frame_sync_edge, frame_sync_polarity, reserved,
2022                  size, chan_1_offset, out_edge, size, chan_1_offset, in_edge, reserved,
2023                  size, chan_2_offset, out_edge, size, chan_2_offset, in_edge, reserved);
2024 }
2025 #endif
2026 
2027 #ifdef ENABLE_BCM_PCM_WBS
2028 void hfp_bcm_prepare_for_sco(hfp_connection_t * hfp_connection){
2029     hfp_connection->bcm_send_write_i2spcm_interface_param = true;
2030     if (hfp_connection->negotiated_codec == HFP_CODEC_MSBC){
2031         hfp_connection->bcm_send_enable_wbs = true;
2032     }
2033 }
2034 void hfp_bcm_write_i2spcm_interface_param(hfp_connection_t * hfp_connection){
2035     uint8_t sample_rate = (hfp_connection->negotiated_codec == HFP_CODEC_MSBC) ? 1 : 0;
2036     // i2s enable, master, 8/16 kHz, 512 kHz
2037     hci_send_cmd(&hci_bcm_write_i2spcm_interface_paramhci_bcm_write_i2spcm_interface_param, 1, 1, sample_rate, 2);
2038 }
2039 #endif
2040 
2041 void hfp_set_hf_callback(btstack_packet_handler_t callback){
2042     hfp_hf_callback = callback;
2043 }
2044 
2045 void hfp_set_ag_callback(btstack_packet_handler_t callback){
2046     hfp_ag_callback = callback;
2047 }
2048 
2049 void hfp_set_ag_rfcomm_packet_handler(btstack_packet_handler_t handler){
2050     hfp_ag_rfcomm_packet_handler = handler;
2051 }
2052 
2053 void hfp_set_hf_rfcomm_packet_handler(btstack_packet_handler_t handler){
2054     hfp_hf_rfcomm_packet_handler = handler;
2055 }
2056 
2057 void hfp_init(void){
2058     hfp_allowed_sco_packet_types = SCO_PACKET_TYPES_ALL;
2059 }
2060 
2061 void hfp_deinit(void){
2062     hfp_allowed_sco_packet_types = 0;
2063     hfp_connections = NULL;
2064     hfp_hf_callback = NULL;
2065     hfp_ag_callback = NULL;
2066     hfp_hf_rfcomm_packet_handler = NULL;
2067     hfp_ag_rfcomm_packet_handler = NULL;
2068     hfp_sco_establishment_active = NULL;
2069     hfp_custom_commands_ag = NULL;
2070     hfp_custom_commands_hf = NULL;
2071     (void) memset(&hfp_sdp_query_context, 0, sizeof(hfp_sdp_query_context_t));
2072     (void) memset(&hfp_sdp_query_request, 0, sizeof(btstack_context_callback_registration_t));
2073 }
2074 
2075 void hfp_set_sco_packet_types(uint16_t packet_types){
2076     hfp_allowed_sco_packet_types = packet_types;
2077 }
2078 
2079 uint16_t hfp_get_sco_packet_types(void){
2080     return hfp_allowed_sco_packet_types;
2081 }
2082 
2083 hfp_link_settings_t hfp_next_link_setting(hfp_link_settings_t current_setting, bool local_eSCO_supported, bool remote_eSCO_supported, bool eSCO_S4_supported, uint8_t negotiated_codec){
2084     int8_t setting = (int8_t) current_setting;
2085     bool can_use_eSCO = local_eSCO_supported && remote_eSCO_supported;
2086     while (setting > 0){
2087         setting--;
2088         // skip if eSCO required but not available
2089         if (hfp_link_settings[setting].eSCO && !can_use_eSCO) continue;
2090         // skip if S4 but not supported
2091         if ((setting == (int8_t) HFP_LINK_SETTINGS_S4) && !eSCO_S4_supported) continue;
2092         // skip wrong codec
2093         if ((hfp_link_settings[setting].codec_mask & (1 << negotiated_codec)) == 0) continue;
2094         // skip disabled packet types
2095         uint16_t required_packet_types = hfp_link_settings[setting].packet_types;
2096         uint16_t allowed_packet_types  = hfp_allowed_sco_packet_types;
2097         if ((required_packet_types & allowed_packet_types) == 0) continue;
2098 
2099         // found matching setting
2100         return (hfp_link_settings_t) setting;
2101     }
2102     return HFP_LINK_SETTINGS_NONE;
2103 }
2104 
2105 static hfp_link_settings_t hfp_next_link_setting_for_connection(hfp_link_settings_t current_setting, hfp_connection_t * hfp_connection, uint8_t eSCO_S4_supported){
2106     bool local_eSCO_supported  = hci_extended_sco_link_supported();
2107     bool remote_eSCO_supported = hci_remote_esco_supported(hfp_connection->acl_handle);
2108     uint8_t negotiated_codec   = hfp_connection->negotiated_codec;
2109     return  hfp_next_link_setting(current_setting, local_eSCO_supported, remote_eSCO_supported, eSCO_S4_supported, negotiated_codec);
2110 }
2111 
2112 void hfp_init_link_settings(hfp_connection_t * hfp_connection, uint8_t eSCO_S4_supported){
2113     // get highest possible link setting
2114     hfp_connection->link_setting = hfp_next_link_setting_for_connection(HFP_LINK_SETTINGS_NONE, hfp_connection, eSCO_S4_supported);
2115     log_info("hfp_init_link_settings: %u", hfp_connection->link_setting);
2116 }
2117 
2118 #define HFP_HF_RX_DEBUG_PRINT_LINE 80
2119 
2120 void hfp_log_rfcomm_message(const char * tag, uint8_t * packet, uint16_t size){
2121 #ifdef ENABLE_LOG_INFO
2122     // encode \n\r
2123     char printable[HFP_HF_RX_DEBUG_PRINT_LINE+2];
2124     int i = 0;
2125     int pos;
2126     for (pos=0 ; (pos < size) && (i < (HFP_HF_RX_DEBUG_PRINT_LINE - 3)) ; pos++){
2127         switch (packet[pos]){
2128             case '\n':
2129                 printable[i++] = '\\';
2130                 printable[i++] = 'n';
2131                 break;
2132             case '\r':
2133                 printable[i++] = '\\';
2134                 printable[i++] = 'r';
2135                 break;
2136             default:
2137                 printable[i++] = packet[pos];
2138                 break;
2139         }
2140     }
2141     printable[i] = 0;
2142     log_info("%s: '%s'", tag, printable);
2143 #endif
2144 }
2145 
2146 void hfp_register_custom_ag_command(hfp_custom_at_command_t * custom_at_command){
2147     btstack_linked_list_add(&hfp_custom_commands_ag, (btstack_linked_item_t *) custom_at_command);
2148 }
2149 
2150 void hfp_register_custom_hf_command(hfp_custom_at_command_t * custom_at_command){
2151     btstack_linked_list_add(&hfp_custom_commands_hf, (btstack_linked_item_t *) custom_at_command);
2152 }
2153 
2154 // HFP H2 Synchronization - might get moved into a hfp_h2.c
2155 
2156 // find position of h2 sync header, returns -1 if not found, or h2 sync position
2157 static int16_t hfp_h2_sync_find(const uint8_t * frame_data, uint16_t frame_len){
2158     uint16_t i;
2159     for (i=0;i<(frame_len - 1);i++){
2160         // check: first byte == 1
2161         uint8_t h2_first_byte = frame_data[i];
2162         if (h2_first_byte == 0x01) {
2163             uint8_t h2_second_byte = frame_data[i + 1];
2164             // check lower nibble of second byte == 0x08
2165             if ((h2_second_byte & 0x0F) == 8) {
2166                 // check if bits 0+2 == bits 1+3
2167                 uint8_t hn = h2_second_byte >> 4;
2168                 if (((hn >> 1) & 0x05) == (hn & 0x05)) {
2169                     return (int16_t) i;
2170                 }
2171             }
2172         }
2173     }
2174     return -1;
2175 }
2176 
2177 static void hfp_h2_sync_reset(hfp_h2_sync_t * hfp_h2_sync){
2178     hfp_h2_sync->frame_len = 0;
2179 }
2180 
2181 void hfp_h2_sync_init(hfp_h2_sync_t * hfp_h2_sync,
2182                       bool (*callback)(bool bad_frame, const uint8_t * frame_data, uint16_t frame_len)){
2183     hfp_h2_sync->callback = callback;
2184     hfp_h2_sync->dropped_bytes = 0;
2185     hfp_h2_sync_reset(hfp_h2_sync);
2186 }
2187 
2188 static void hfp_h2_report_bad_frames(hfp_h2_sync_t *hfp_h2_sync){
2189     // report bad frames
2190     while (hfp_h2_sync->dropped_bytes >= HFP_H2_SYNC_FRAME_SIZE){
2191         hfp_h2_sync->dropped_bytes -= HFP_H2_SYNC_FRAME_SIZE;
2192         (void)(*hfp_h2_sync->callback)(true,NULL, HFP_H2_SYNC_FRAME_SIZE);
2193     }
2194 }
2195 
2196 static void hfp_h2_sync_drop_bytes(hfp_h2_sync_t * hfp_h2_sync, uint16_t bytes_to_drop){
2197     btstack_assert(bytes_to_drop <= hfp_h2_sync->frame_len);
2198     memmove(hfp_h2_sync->frame_data, &hfp_h2_sync->frame_data[bytes_to_drop], hfp_h2_sync->frame_len - bytes_to_drop);
2199     hfp_h2_sync->dropped_bytes += bytes_to_drop;
2200     hfp_h2_sync->frame_len     -= bytes_to_drop;
2201     hfp_h2_report_bad_frames(hfp_h2_sync);
2202 }
2203 
2204 void hfp_h2_sync_process(hfp_h2_sync_t *hfp_h2_sync, bool bad_frame, const uint8_t *frame_data, uint16_t frame_len) {
2205 
2206     if (bad_frame){
2207         // drop all data
2208         hfp_h2_sync->dropped_bytes += hfp_h2_sync->frame_len;
2209         hfp_h2_sync->frame_len = 0;
2210         // all new data is bad, too
2211         hfp_h2_sync->dropped_bytes += frame_len;
2212         // report frames
2213         hfp_h2_report_bad_frames(hfp_h2_sync);
2214         return;
2215     }
2216 
2217     while (frame_len > 0){
2218         // Fill hfp_h2_sync->frame_buffer
2219         uint16_t bytes_free_in_frame_buffer = HFP_H2_SYNC_FRAME_SIZE - hfp_h2_sync->frame_len;
2220         uint16_t bytes_to_append = btstack_min(frame_len, bytes_free_in_frame_buffer);
2221         memcpy(&hfp_h2_sync->frame_data[hfp_h2_sync->frame_len], frame_data, bytes_to_append);
2222         frame_data             += bytes_to_append;
2223         frame_len              -= bytes_to_append;
2224         hfp_h2_sync->frame_len += bytes_to_append;
2225         // check complete frame for h2 sync
2226         if (hfp_h2_sync->frame_len == HFP_H2_SYNC_FRAME_SIZE){
2227             bool valid_frame = true;
2228             int16_t h2_pos = hfp_h2_sync_find(hfp_h2_sync->frame_data, hfp_h2_sync->frame_len);
2229             if (h2_pos < 0){
2230                 // no h2 sync, no valid frame, keep last byte if it is 0x01
2231                 if (hfp_h2_sync->frame_data[HFP_H2_SYNC_FRAME_SIZE-1] == 0x01){
2232                     hfp_h2_sync_drop_bytes(hfp_h2_sync, HFP_H2_SYNC_FRAME_SIZE - 1);
2233                 } else {
2234                     hfp_h2_sync_drop_bytes(hfp_h2_sync, HFP_H2_SYNC_FRAME_SIZE);
2235                 }
2236                 valid_frame = false;
2237             }
2238             else if (h2_pos > 0){
2239                 // drop data before h2 sync
2240                 hfp_h2_sync_drop_bytes(hfp_h2_sync, h2_pos);
2241                 valid_frame = false;
2242             }
2243             if (valid_frame) {
2244                 // h2 sync at pos 0 and complete frame
2245                 bool codec_ok = (*hfp_h2_sync->callback)(false, hfp_h2_sync->frame_data, hfp_h2_sync->frame_len);
2246                 if (codec_ok){
2247                     hfp_h2_sync_reset(hfp_h2_sync);
2248                 } else {
2249                     // drop first two bytes
2250                     hfp_h2_sync_drop_bytes(hfp_h2_sync, 2);
2251                 }
2252             }
2253         }
2254     }
2255 }
2256