BluetoothSerial SSP Authentication with callbacks (#4634)

Added authentication callbacks and example, resolves #4622.

libraries/BluetoothSerial/examples/SerialToSerialBT_SSP_pairing/SerialToSerialBT_SSP_pairing.ino

+//This example code is in the Public Domain (or CC0 licensed, at your option.)
+//By Richard Li - 2020
+//
+//This example creates a bridge between Serial and Classical Bluetooth (SPP with authentication)
+//and also demonstrate that SerialBT have the same functionalities of a normal Serial
+
+#include "BluetoothSerial.h"
+
+#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
+#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
+#endif
+
+BluetoothSerial SerialBT;
+boolean confirmRequestPending = true;
+
+void BTConfirmRequestCallback(uint32_t numVal)
+{
+  confirmRequestPending = true;
+  Serial.println(numVal);
+}
+
+void BTAuthCompleteCallback(boolean success)
+{
+  confirmRequestPending = false;
+  if (success)
+  {
+    Serial.println("Pairing success!!");
+  }
+  else
+  {
+    Serial.println("Pairing failed, rejected by user!!");
+  }
+}
+
+
+void setup()
+{
+  Serial.begin(115200);
+  SerialBT.enableSSP();
+  SerialBT.onConfirmRequest(BTConfirmRequestCallback);
+  SerialBT.onAuthComplete(BTAuthCompleteCallback);
+  SerialBT.begin("ESP32test"); //Bluetooth device name
+  Serial.println("The device started, now you can pair it with bluetooth!");
+}
+
+void loop()
+{
+  if (confirmRequestPending)
+  {
+    if (Serial.available())
+    {
+      int dat = Serial.read();
+      if (dat == 'Y' || dat == 'y')
+      {
+        SerialBT.confirmReply(true);
+      }
+      else
+      {
+        SerialBT.confirmReply(false);
+      }
+    }
+  }
+  else
+  {
+    if (Serial.available())
+    {
+      SerialBT.write(Serial.read());
+    }
+    if (SerialBT.available())
+    {
+      Serial.write(SerialBT.read());
+    }
+    delay(20);
+  }
+}

libraries/BluetoothSerial/src/BluetoothSerial.cpp

@@ -51,6 +51,9 @@ static EventGroupHandle_t _spp_event_group = NULL;
 static boolean secondConnectionAttempt;
 static esp_spp_cb_t * custom_spp_callback = NULL;
 static BluetoothSerialDataCb custom_data_callback = NULL;
+static esp_bd_addr_t current_bd_addr;
+static ConfirmRequestCb confirm_request_callback = NULL;
+static AuthCompleteCb auth_complete_callback = NULL;
 
 #define INQ_LEN 0x10
 #define INQ_NUM_RSPS 20
@@ -398,8 +401,14 @@ static void esp_bt_gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *pa
         case ESP_BT_GAP_AUTH_CMPL_EVT:
             if (param->auth_cmpl.stat == ESP_BT_STATUS_SUCCESS) {
                 log_v("authentication success: %s", param->auth_cmpl.device_name);
+                if (auth_complete_callback) {
+                    auth_complete_callback(true);
+                }
             } else {
                 log_e("authentication failed, status:%d", param->auth_cmpl.stat);
+                if (auth_complete_callback) {
+                    auth_complete_callback(false);
+                }
             }
             break;
 
@@ -421,7 +430,13 @@ static void esp_bt_gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *pa
        
         case ESP_BT_GAP_CFM_REQ_EVT:
             log_i("ESP_BT_GAP_CFM_REQ_EVT Please compare the numeric value: %d", param->cfm_req.num_val);
-            esp_bt_gap_ssp_confirm_reply(param->cfm_req.bda, true);
+            if (confirm_request_callback) {
+                memcpy(current_bd_addr, param->cfm_req.bda, sizeof(esp_bd_addr_t));
+                confirm_request_callback(param->cfm_req.num_val);
+            }
+            else {
+                esp_bt_gap_ssp_confirm_reply(param->cfm_req.bda, true);
+            }
             break;
 
         case ESP_BT_GAP_KEY_NOTIF_EVT:
@@ -500,7 +515,9 @@ static bool _init_bt(const char *deviceName)
         }
     }
 
-    if (_isMaster && esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
+    // Why only master need this?  Slave need this during pairing as well
+//    if (_isMaster && esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
+    if (esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
         log_e("gap register failed");
         return false;
     }
@@ -672,6 +689,22 @@ void BluetoothSerial::end()
     _stop_bt();
 }
 
+void BluetoothSerial::onConfirmRequest(ConfirmRequestCb cb)
+{
+    confirm_request_callback = cb;
+}
+
+void BluetoothSerial::onAuthComplete(AuthCompleteCb cb)
+{
+    auth_complete_callback = cb;
+}
+
+void BluetoothSerial::confirmReply(boolean confirm)
+{
+    esp_bt_gap_ssp_confirm_reply(current_bd_addr, confirm);  
+}
+
+
 esp_err_t BluetoothSerial::register_callback(esp_spp_cb_t * callback)
 {
     custom_spp_callback = callback;

libraries/BluetoothSerial/src/BluetoothSerial.h

@@ -25,6 +25,8 @@
 #include <functional>
 
 typedef std::function<void(const uint8_t *buffer, size_t size)> BluetoothSerialDataCb;
+typedef std::function<void(uint32_t num_val)> ConfirmRequestCb;
+typedef std::function<void(boolean success)> AuthCompleteCb;
 
 class BluetoothSerial: public Stream
 {
@@ -44,6 +46,10 @@ class BluetoothSerial: public Stream
         void end(void);
         void onData(BluetoothSerialDataCb cb);
         esp_err_t register_callback(esp_spp_cb_t * callback);
+        
+        void onConfirmRequest(ConfirmRequestCb cb);
+        void onAuthComplete(AuthCompleteCb cb);
+        void confirmReply(boolean confirm);
 
         void enableSSP();
         bool setPin(const char *pin);