Add smartConfig support (espressif#136)

* smartConfig support

* fixed bug, added example

* added _smartConfigDone = ture

* changed example name, added explanation

Author: seopyoon

libraries/WiFi/examples/WiFiSmartConfig/WiFiSmartConfig.ino

@@ -0,0 +1,36 @@
+#include "WiFi.h"
+
+void setup() {
+  Serial.begin(115200);
+
+  //Init WiFi as Station, start SmartConfig
+  WiFi.mode(WIFI_AP_STA);
+  WiFi.beginSmartConfig();
+
+  //Wait for SmartConfig packet from mobile
+  Serial.println("Waiting for SmartConfig.");
+  while (!WiFi.smartConfigDone()) {
+    delay(500);
+    Serial.print(".");
+  }
+
+  Serial.println("");
+  Serial.println("SmartConfig received.");
+
+  //Wait for WiFi to connect to AP
+  Serial.println("Waiting for WiFi");
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+
+  Serial.println("WiFi Connected.");
+
+  Serial.print("IP Address: ");
+  Serial.println(WiFi.localIP());
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+
+}

libraries/WiFi/src/WiFiSTA.cpp

@@ -40,6 +40,7 @@ extern "C" {
 #include <lwip/ip_addr.h>
 #include "lwip/err.h"
 #include "lwip/dns.h"
+#include <esp_smartconfig.h>
 }
 
 extern "C" void esp_schedule();
@@ -498,3 +499,64 @@ IPv6Address WiFiSTAClass::localIPv6()
     }
     return IPv6Address(addr.addr);
 }
+
+
+bool WiFiSTAClass::_smartConfigStarted = false;
+bool WiFiSTAClass::_smartConfigDone = false;
+
+
+bool WiFiSTAClass::beginSmartConfig() {
+    if (_smartConfigStarted) {
+        return false;
+    }
+
+    if (!WiFi.mode(WIFI_STA)) {
+        return false;
+    }
+
+
+    esp_err_t err;
+    err = esp_smartconfig_start(reinterpret_cast<sc_callback_t>(&WiFiSTAClass::_smartConfigCallback), 1);
+    if (err == ESP_OK) {
+        _smartConfigStarted = true;
+        _smartConfigDone = false;
+        return true;
+    }
+    return false;
+}
+
+bool WiFiSTAClass::stopSmartConfig() {
+    if (!_smartConfigStarted) {
+        return true;
+    }
+
+    if (esp_smartconfig_stop() == ESP_OK) {
+        _smartConfigStarted = false;
+        return true;
+    }
+
+    return false;
+}
+
+bool WiFiSTAClass::smartConfigDone() {
+    if (!_smartConfigStarted) {
+        return false;
+    }
+
+    return _smartConfigDone;
+}
+
+void WiFiSTAClass::_smartConfigCallback(uint32_t st, void* result) {
+    smartconfig_status_t status = (smartconfig_status_t) st;
+    if (status == SC_STATUS_LINK) {
+        wifi_sta_config_t *sta_conf = reinterpret_cast<wifi_sta_config_t *>(result);
+
+        esp_wifi_set_config(WIFI_IF_AP, (wifi_config_t *)sta_conf);
+        esp_wifi_disconnect();
+        esp_wifi_connect();
+
+        _smartConfigDone = true;
+    } else if (status == SC_STATUS_LINK_OVER) {
+        WiFi.stopSmartConfig();
+    }
+}

libraries/WiFi/src/WiFiSTA.h

@@ -85,6 +85,16 @@ class WiFiSTAClass
     static wl_status_t _status;
     static bool _useStaticIp;
 
+public: 
+    bool beginSmartConfig();
+    bool stopSmartConfig();
+    bool smartConfigDone();
+
+protected:
+    static bool _smartConfigStarted;
+    static bool _smartConfigDone;
+    static void _smartConfigCallback(uint32_t status, void* result);
+
 };