gap: support reading RSSI for Classic+LE using gap_read_rssi. Emits GAP_EVENT_RSSI_MEASUREMENT

CHANGELOG.md

@@ -11,7 +11,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 
 ### Added
-- gap: allow to reject GAP classic connection via gap_register_classic_connection_filter
+- GAP: allow to reject GAP classic connection via gap_register_classic_connection_filter
+- GAP: support reading RSSI for Classic+LE using gap_read_rssi. Emits GAP_EVENT_RSSI_MEASUREMENT
 
 ## Changed
 

src/btstack_defines.h

@@ -1046,6 +1046,14 @@ typedef uint8_t sm_key_t[16];
  */
 #define GAP_EVENT_INQUIRY_COMPLETE                            0xE4
 
+/**
+ * @format H1
+ * @param con_handle
+ * @param rssi (signed integer -127..127)
+ * @note Classic: rssi is in dB relative to Golden Receive Power Range
+ * @note LE: rssi is absolute dBm
+ */
+#define GAP_EVENT_RSSI_MEASUREMENT                            0xE5
 
 // Meta Events, see below for sub events
 #define HCI_EVENT_HSP_META                                 0xE8

src/btstack_event.h

@@ -3258,6 +3258,25 @@ static inline uint8_t gap_event_inquiry_complete_get_status(const uint8_t * even
     return event[2];
 }
 
+/**
+ * @brief Get field con_handle from event GAP_EVENT_RSSI_MEASUREMENT
+ * @param event packet
+ * @return con_handle
+ * @note: btstack_type H
+ */
+static inline hci_con_handle_t gap_event_rssi_measurement_get_con_handle(const uint8_t * event){
+    return little_endian_read_16(event, 2);
+}
+/**
+ * @brief Get field rssi from event GAP_EVENT_RSSI_MEASUREMENT
+ * @param event packet
+ * @return rssi
+ * @note: btstack_type 1
+ */
+static inline uint8_t gap_event_rssi_measurement_get_rssi(const uint8_t * event){
+    return event[4];
+}
+
 /**
  * @brief Get field status from event HCI_SUBEVENT_LE_CONNECTION_COMPLETE
  * @param event packet

src/gap.h

@@ -553,6 +553,13 @@ int gap_inquiry_stop(void);
  */
 int gap_remote_name_request(bd_addr_t addr, uint8_t page_scan_repetition_mode, uint16_t clock_offset);
 
+/**
+ * @brief Read RSSI
+ * @param con_handle
+ * @events: GAP_EVENT_RSSI_MEASUREMENT
+ */
+int gap_read_rssi(hci_con_handle_t con_handle);
+
 /**
  * @brief Legacy Pairing Pin Code Response
  * @param addr

src/hci.c

@@ -1916,6 +1916,15 @@ static void event_handler(uint8_t *packet, int size){
                              hci_stack->sco_data_packet_length, hci_stack->sco_packets_total_num); 
                 }
             }
+            if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_rssi)){
+                if (packet[5] == 0){
+                    uint8_t event[5];
+                    event[0] = GAP_EVENT_RSSI_MEASUREMENT;
+                    event[1] = 3;
+                    memcpy(&event[2], &packet[6], 3);
+                    hci_emit_event(event, sizeof(event), 1);
+                }
+            }
 #ifdef ENABLE_BLE
             if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_read_buffer_size)){
                 hci_stack->le_data_packets_length = little_endian_read_16(packet, 6);
@@ -3581,6 +3590,12 @@ static void hci_run(void){
         // no further commands if connection is about to get shut down
         if (connection->state == SENT_DISCONNECT) continue;
 
+        if (connection->authentication_flags & READ_RSSI){
+            connectionClearAuthenticationFlags(connection, READ_RSSI);
+            hci_send_cmd(&hci_read_rssi, connection->con_handle);
+            return;
+        }
+
 #ifdef ENABLE_CLASSIC
         if (connection->authentication_flags & HANDLE_LINK_KEY_REQUEST){
             log_info("responding to link key request");
@@ -4957,6 +4972,14 @@ int gap_remote_name_request(bd_addr_t addr, uint8_t page_scan_repetition_mode, u
     return 0;
 }
 
+int gap_read_rssi(hci_con_handle_t con_handle){
+    hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
+    if (hci_connection == NULL) return 0;
+    connectionSetAuthenticationFlags(hci_connection, READ_RSSI);
+    hci_run();
+    return 1;
+}
+
 static int gap_pairing_set_state_and_run(bd_addr_t addr, uint8_t state){
     hci_stack->gap_pairing_state = state;
     memcpy(hci_stack->gap_pairing_addr, addr, 6);

src/hci.h

@@ -197,6 +197,9 @@ typedef enum {
 
     // connection status
     CONNECTION_ENCRYPTED           = 0x8000,
+
+    // errands
+    READ_RSSI                      = 0x10000,
 } hci_authentication_flags_t;
 
 /**
@@ -512,11 +515,11 @@ typedef struct {
     btstack_timer_source_t timeout_sco;
 #endif /* ENABLE_CLASSIC */
 
-    // errands
+    // authentication and other errands
     uint32_t authentication_flags;
 
     btstack_timer_source_t timeout;
-    
+
     // timeout in system ticks (HAVE_EMBEDDED_TICK) or milliseconds (HAVE_EMBEDDED_TIME_MS)
     uint32_t timestamp;