idf4.0_compat: Minor changes for IDF 4.0 compatibility

If IDF version being used is 4.0, following changes will happen:
- tcpip_adapter will be used, instead of esp_netif.
- MQTT port 8883 will be used, even if 443 is chosen, because
443 requires ALPN options in MQTT, which aren't supported in IDF 4.0

Author: shahpiyushv

README.md

@@ -18,6 +18,10 @@ The key features of ESP RainMaker are:
 2. Zero configuration required on the Cloud.
 3. Phone apps that dynamically render the UI as per the device information.
 
+## Supported ESP-IDF versions
+
+ESP RainMaker can work with ESP IDF 4.0 and above.
+
 ## Phone Apps
 
 ### Android

components/esp_rainmaker/src/mqtt/esp_rmaker_mqtt.c

@@ -19,9 +19,24 @@
 #include <freertos/event_groups.h>
 #include <esp_log.h>
 #include <mqtt_client.h>
-
 #include <esp_rmaker_mqtt.h>
 
+#include <esp_idf_version.h>
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(4, 1, 0)
+// Features supported in 4.1
+
+#ifdef CONFIG_ESP_RMAKER_MQTT_PORT_443
+#define ESP_RMAKER_MQTT_USE_PORT_443
+#endif
+
+#else
+
+#ifdef CONFIG_ESP_RMAKER_MQTT_PORT_443
+#warning "Port 443 not supported in idf versions below 4.1. Using 8883 instead."
+#endif
+
+#endif /* !IDF4.1 */
+
 static const char *TAG = "esp_rmaker_mqtt";
 
 #define MAX_MQTT_SUBSCRIPTIONS      5
@@ -212,9 +227,9 @@ esp_err_t esp_rmaker_mqtt_disconnect(void)
     }
     return err;
 }
-#ifdef CONFIG_ESP_RMAKER_MQTT_PORT_443
+#ifdef ESP_RMAKER_MQTT_USE_PORT_443
 static const char *alpn_protocols[] = { "x-amzn-mqtt-ca", NULL };
-#endif /* CONFIG_ESP_RMAKER_MQTT_PORT_443 */
+#endif /* ESP_RMAKER_MQTT_USE_PORT_443 */
 esp_err_t esp_rmaker_mqtt_init(esp_rmaker_mqtt_config_t *config)
 {
     if (mqtt_data) {
@@ -229,13 +244,12 @@ esp_err_t esp_rmaker_mqtt_init(esp_rmaker_mqtt_config_t *config)
     mqtt_data->config = config;
     const esp_mqtt_client_config_t mqtt_client_cfg = {
         .host = config->mqtt_host,
-#ifdef CONFIG_ESP_RMAKER_MQTT_PORT_443
+#ifdef ESP_RMAKER_MQTT_USE_PORT_443
         .port = 443,
         .alpn_protos = alpn_protocols,
-#endif /* CONFIG_ESP_RMAKER_MQTT_PORT_443 */
-#ifdef CONFIG_ESP_RMAKER_MQTT_PORT_8883
+#else
         .port = 8883,
-#endif /* CONFIG_ESP_RMAKER_MQTT_PORT_8883 */
+#endif /* !ESP_RMAKER_MQTT_USE_PORT_443 */
         .cert_pem = (const char *)config->server_cert,
         .client_cert_pem = (const char *)config->client_cert,
         .client_key_pem = (const char *)config->client_key,

examples/common/app_wifi/app_wifi.c

@@ -12,6 +12,18 @@
 #include <esp_wifi.h>
 #include <esp_event.h>
 #include <esp_log.h>
+#include <esp_idf_version.h>
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(4, 1, 0)
+// Features supported in 4.1+
+#define ESP_NETIF_SUPPORTED
+#endif
+
+#ifdef ESP_NETIF_SUPPORTED
+#include <esp_netif.h>
+#else
+#include <tcpip_adapter.h>
+#endif
+
 #include <wifi_provisioning/manager.h>
 #ifdef CONFIG_APP_WIFI_PROV_TRANSPORT_BLE
 #include <wifi_provisioning/scheme_ble.h>
@@ -181,7 +193,11 @@ static esp_err_t get_device_pop(char *pop, size_t max, app_wifi_pop_type_t pop_t
 void app_wifi_init(void)
 {
     /* Initialize TCP/IP */
+#ifdef ESP_NETIF_SUPPORTED
     esp_netif_init();
+#else
+    tcpip_adapter_init();
+#endif
 
     /* Initialize the event loop */
     ESP_ERROR_CHECK(esp_event_loop_create_default());
@@ -193,7 +209,9 @@ void app_wifi_init(void)
     ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL));
 
     /* Initialize Wi-Fi including netif with default config */
+#ifdef ESP_NETIF_SUPPORTED
     esp_netif_create_default_wifi_sta();
+#endif
     wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
     ESP_ERROR_CHECK(esp_wifi_init(&cfg));
 }
@@ -236,7 +254,9 @@ esp_err_t app_wifi_start(app_wifi_pop_type_t pop_type)
     /* If device is not yet provisioned start provisioning service */
     if (!provisioned) {
         ESP_LOGI(TAG, "Starting provisioning");
+#ifdef ESP_NETIF_SUPPORTED
         esp_netif_create_default_wifi_ap();
+#endif
 
         /* What is the Device Service Name that we want
          * This translates to :