feat(example): Added DNS over HTTPS (DoH) example

2024-09-30 22:03:37 +10:00
parent 5462240135
commit 967603b5aa
22 changed files with 1392 additions and 0 deletions
@@ -0,0 +1,3 @@
+idf_component_register(SRCS "time_sync.c"
+                    INCLUDE_DIRS "include"
+                    PRIV_REQUIRES nvs_flash esp_event esp_netif esp_timer)
@@ -0,0 +1,18 @@
+menu "Time Sync Configuration"
+
+    config TIME_SYNC_NTP_SERVER
+        string "NTP Server"
+        default "pool.ntp.org"
+        help
+            Configure the NTP server for time synchronization.
+            The default is set to "pool.ntp.org".
+
+    config TIME_SYNC_NTP_UPDATE_PERIOD
+        int "NTP Time Update Interval (in hours)"
+        default 24
+        range 1 24
+        help
+            The time interval in hours for updating the system time using the NTP server.
+            For example, if set to 12, the system will update the time from the NTP server every 12 hours.
+
+endmenu
@@ -0,0 +1,5 @@
+## IDF Component Manager Manifest File
+version: 0.1.0
+dependencies:
+  idf:
+    version: ">=5.1"
@@ -0,0 +1,46 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Update system time from NVS or SNTP if not available.
+ *
+ * This function retrieves the stored system time from NVS. If the time is not found,
+ * it synchronizes with the SNTP server and updates the time in NVS.
+ *
+ * @return esp_err_t ESP_OK on success, ESP_FAIL on failure.
+ */
+esp_err_t update_time_from_nvs(void);
+
+/**
+ * @brief Fetch the current system time and store it in NVS.
+ *
+ * This function initializes SNTP, retrieves the current system time, and stores
+ * it in Non-Volatile Storage (NVS). In case of failure, an error message is logged.
+ *
+ * @param[in] args Unused argument placeholder.
+ * @return esp_err_t ESP_OK on success, ESP_FAIL on failure.
+ */
+esp_err_t fetch_and_store_time_in_nvs(void*);
+
+/**
+ * @brief Sets up periodic time updates.
+ *
+ * If the reset reason is power-on, this function updates the system time from NVS.
+ * It also creates a periodic timer to regularly fetch and store the time in NVS
+ * using `fetch_and_store_time_in_nvs` as the callback.
+ *
+ * @return void
+ */
+void setup_periodic_time_updates(void);
+
+#ifdef __cplusplus
+}
+#endif
@@ -0,0 +1,192 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+#include "esp_log.h"
+#include "esp_system.h"
+#include "nvs_flash.h"
+#include "nvs.h"
+#include "esp_netif_sntp.h"
+#include "esp_timer.h"
+
+#include "lwip/err.h"
+#include "lwip/sockets.h"
+#include "lwip/sys.h"
+
+#include "time_sync.h"
+
+static const char *TAG = "time_sync";
+
+#define STORAGE_NAMESPACE "storage"
+
+/* Timer interval once every day (24 Hours) */
+#define SECONDS_PER_HOUR 3600ULL
+#define MICROSECONDS_PER_SECOND 1000000ULL
+#define TIME_PERIOD ((uint64_t)CONFIG_TIME_SYNC_NTP_UPDATE_PERIOD * SECONDS_PER_HOUR * MICROSECONDS_PER_SECOND) // Convert hours to microseconds
+
+/**
+ * @brief Initialize SNTP service with predefined servers.
+ *
+ * This function sets up the SNTP service to sync time.
+ */
+void initialize_sntp(void)
+{
+    ESP_LOGI(TAG, "Initializing SNTP");
+    esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG_MULTIPLE(1,
+                                                                      ESP_SNTP_SERVER_LIST(CONFIG_TIME_SYNC_NTP_SERVER));
+    esp_netif_sntp_init(&config);
+}
+
+/**
+ * @brief Obtain system time from SNTP service.
+ *
+ * This function attempts to synchronize the system time using SNTP, retrying
+ * up to 10 times if necessary. If the synchronization is successful, it returns
+ * ESP_OK, otherwise ESP_FAIL.
+ *
+ * @return esp_err_t ESP_OK on success, ESP_FAIL on failure.
+ */
+static esp_err_t obtain_time(void)
+{
+    /* wait for time to be set */
+    int retry = 0;
+    const int retry_count = 10;
+    while (esp_netif_sntp_sync_wait(pdMS_TO_TICKS(2000)) != ESP_OK && ++retry < retry_count) {
+        ESP_LOGI(TAG, "Waiting for system time to be set... (%d/%d)", retry, retry_count);
+    }
+    if (retry == retry_count) {
+        return ESP_FAIL;
+    }
+    return ESP_OK;
+}
+
+/**
+ * @brief Fetch the current system time and store it in NVS.
+ *
+ * This function initializes SNTP, retrieves the current system time, and stores
+ * it in Non-Volatile Storage (NVS). In case of failure, an error message is logged.
+ *
+ * @param[in] args Unused argument placeholder.
+ * @return esp_err_t ESP_OK on success, ESP_FAIL on failure.
+ */
+esp_err_t fetch_and_store_time_in_nvs(void *args)
+{
+    nvs_handle_t my_handle = 0;
+    esp_err_t err;
+
+    initialize_sntp();
+    if (obtain_time() != ESP_OK) {
+        err = ESP_FAIL;
+        goto exit;
+    }
+
+    time_t now;
+    time(&now);
+
+    /* Open */
+    err = nvs_open(STORAGE_NAMESPACE, NVS_READWRITE, &my_handle);
+    if (err != ESP_OK) {
+        goto exit;
+    }
+
+    /* Write */
+    err = nvs_set_i64(my_handle, "timestamp", now);
+    if (err != ESP_OK) {
+        goto exit;
+    }
+
+    err = nvs_commit(my_handle);
+    if (err != ESP_OK) {
+        goto exit;
+    }
+
+exit:
+    if (my_handle != 0) {
+        nvs_close(my_handle);
+    }
+    esp_netif_sntp_deinit();
+
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Error updating time in nvs");
+    } else {
+        ESP_LOGI(TAG, "Updated time in NVS");
+    }
+    return err;
+}
+
+/**
+ * @brief Update system time from NVS or SNTP if not available.
+ *
+ * This function retrieves the stored system time from NVS. If the time is not found,
+ * it synchronizes with the SNTP server and updates the time in NVS.
+ *
+ * @return esp_err_t ESP_OK on success, ESP_FAIL on failure.
+ */
+esp_err_t update_time_from_nvs(void)
+{
+    nvs_handle_t my_handle = 0;
+    esp_err_t err;
+
+    err = nvs_open(STORAGE_NAMESPACE, NVS_READWRITE, &my_handle);
+    if (err != ESP_OK) {
+        ESP_LOGE(TAG, "Error opening NVS");
+        goto exit;
+    }
+
+    int64_t timestamp = 0;
+
+    err = nvs_get_i64(my_handle, "timestamp", &timestamp);
+    if (err == ESP_ERR_NVS_NOT_FOUND) {
+        ESP_LOGI(TAG, "Time not found in NVS. Syncing time from SNTP server.");
+        if (fetch_and_store_time_in_nvs(NULL) != ESP_OK) {
+            err = ESP_FAIL;
+        } else {
+            err = ESP_OK;
+        }
+    } else if (err == ESP_OK) {
+        struct timeval get_nvs_time;
+        get_nvs_time.tv_sec = timestamp;
+        settimeofday(&get_nvs_time, NULL);
+    }
+
+exit:
+    if (my_handle != 0) {
+        nvs_close(my_handle);
+    }
+    return err;
+}
+
+/**
+ * @brief Sets up periodic time updates.
+ *
+ * If the reset reason is power-on, this function updates the system time from NVS.
+ * It also creates a periodic timer to regularly fetch and store the time in NVS
+ * using `fetch_and_store_time_in_nvs` as the callback.
+ *
+ * @return void
+ */
+void setup_periodic_time_updates(void)
+{
+    /* Check if the reset reason is power-on, and update time from NVS */
+    if (esp_reset_reason() == ESP_RST_POWERON) {
+        ESP_LOGI(TAG, "Updating time from NVS");
+        ESP_ERROR_CHECK(update_time_from_nvs());
+    }
+
+    /* Set up a periodic timer to fetch and store the time in NVS */
+    const esp_timer_create_args_t nvs_update_timer_args = {
+        .callback = (void *) &fetch_and_store_time_in_nvs,
+    };
+
+    esp_timer_handle_t nvs_update_timer;
+    ESP_ERROR_CHECK(esp_timer_create(&nvs_update_timer_args, &nvs_update_timer));
+    ESP_ERROR_CHECK(esp_timer_start_periodic(nvs_update_timer, TIME_PERIOD));
+}