examples: Add CoAP client demo

Test CoAP protocol client

examples/23_coap_client/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := coap_client
+
+include $(IDF_PATH)/make/project.mk
+

examples/23_coap_client/main/Kconfig.projbuild

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+menu "Example Configuration"
+
+config TARGET_DOMAIN
+    string "Target Domain"
+    default "californium.eclipse.org"
+    help
+        Target domain for the example to connect to.
+
+config TARGET_DOMAIN_URI
+    string "Target Uri"
+    default "coap://californium.eclipse.org"
+    help
+        Target uri for the example to use.
+
+config TARGET_PORT_NUMBER
+    int "Target port number"
+    range 0 65535
+    default 5683
+    help
+        Target port number for the example to connect to.
+
+config WIFI_SSID
+    string "WiFi SSID"
+    default "myssid"
+    help
+        SSID (network name) for the example to connect to.
+
+config WIFI_PASSWORD
+    string "WiFi Password"
+    default "mypassword"
+    help
+        WiFi password (WPA or WPA2) for the example to use.
+
+endmenu

examples/23_coap_client/main/coap_client.c

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+/* CoAP client Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include "coap_client.h"
+
+#include <string.h>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+
+#include "esp_log.h"
+#include "esp_wifi.h"
+#include "esp_event_loop.h"
+
+#include "nvs_flash.h"
+#include <sys/socket.h>
+
+#include "coap_config.h"
+#include "resource.h"
+#include "coap.h"
+
+
+static EventGroupHandle_t wifi_event_group;
+
+/* The event group allows multiple bits for each event,
+   but we only care about one event - are we connected
+   to the AP with an IP? */
+const static int CONNECTED_BIT = BIT0;
+
+const static char *TAG = "CoAP_demo";
+
+static void message_handler(struct coap_context_t *ctx, const coap_endpoint_t *local_interface, const coap_address_t *remote,
+              coap_pdu_t *sent, coap_pdu_t *received,
+                const coap_tid_t id)
+{
+	unsigned char* data = NULL;
+	size_t data_len;
+	if (COAP_RESPONSE_CLASS(received->hdr->code) == 2) {
+		if (coap_get_data(received, &data_len, &data)) {
+			printf("Received: %s\n", data);
+		}
+	}
+}
+
+static void coap_demo_thread(void *p)
+{
+	coap_context_t*   ctx = NULL;
+	coap_address_t    dst_addr, src_addr;
+	static coap_uri_t uri;
+	fd_set            readfds;
+	struct timeval    tv;
+	int flags, result;
+	coap_pdu_t*       request = NULL;
+	const char*       server_uri = COAP_DEFAULT_DEMO_URI;
+	uint8_t     get_method = 1;
+
+	coap_address_init(&src_addr);
+	src_addr.addr.sin.sin_family      = AF_INET;
+	src_addr.addr.sin.sin_port        = htons(0);
+	src_addr.addr.sin.sin_addr.s_addr = INADDR_ANY;
+
+	ctx = coap_new_context(&src_addr);
+	if (ctx) {
+		coap_address_init(&dst_addr);
+		dst_addr.addr.sin.sin_family      = AF_INET;
+		dst_addr.addr.sin.sin_port        = htons(COAP_DEFAULT_PORT);
+		dst_addr.addr.sin.sin_addr.s_addr = inet_addr(COAP_DEFAULT_DEMO_ADDR);
+
+		coap_split_uri((const uint8_t *)server_uri, strlen(server_uri), &uri);
+		request            = coap_new_pdu();
+		if (request){
+			request->hdr->type = COAP_MESSAGE_CON;
+			request->hdr->id   = coap_new_message_id(ctx);
+			request->hdr->code = get_method;
+			coap_add_option(request, COAP_OPTION_URI_PATH, uri.path.length, uri.path.s);
+
+			coap_register_response_handler(ctx, message_handler);
+			coap_send_confirmed(ctx, ctx->endpoint, &dst_addr, request);
+
+			flags = fcntl(ctx->sockfd, F_GETFL, 0);
+			fcntl(ctx->sockfd, F_SETFL, flags|O_NONBLOCK);
+
+			tv.tv_usec = COAP_DEFAULT_TIME_USEC;
+			tv.tv_sec = COAP_DEFAULT_TIME_SEC;
+
+			for(;;) {
+				FD_ZERO(&readfds);
+				FD_CLR( ctx->sockfd, &readfds );
+				FD_SET( ctx->sockfd, &readfds );
+				result = select( FD_SETSIZE, &readfds, 0, 0, &tv );
+				if (result > 0) {
+					if (FD_ISSET( ctx->sockfd, &readfds ))
+						coap_read(ctx);
+				} else if (result < 0) {
+					break;
+				} else {
+					printf("select timeout\n");
+				}
+			}
+		}
+		coap_free_context(ctx);
+	}
+
+	vTaskDelete(NULL);
+}
+
+static void coap_server_init(void)
+{
+    int ret = pdPASS;
+    xTaskHandle coap_handle = NULL;
+
+    ret = xTaskCreate(coap_demo_thread,
+                      COAP_DEMO_THREAD_NAME,
+                      COAP_DEMO_THREAD_STACK_WORDS,
+                      NULL,
+                      COAP_DEMO_THREAD_PRORIOTY,
+                      &coap_handle);
+
+    if (ret != pdPASS)  {
+        ESP_LOGI(TAG, "create thread %s failed", COAP_DEMO_THREAD_NAME);
+    }
+}
+
+static esp_err_t wifi_event_handler(void *ctx, system_event_t *event)
+{
+    switch(event->event_id) {
+    case SYSTEM_EVENT_STA_START:
+        esp_wifi_connect();
+        break;
+    case SYSTEM_EVENT_STA_GOT_IP:
+        xEventGroupSetBits(wifi_event_group, CONNECTED_BIT);
+        coap_server_init();
+        break;
+    case SYSTEM_EVENT_STA_DISCONNECTED:
+        /* This is a workaround as ESP32 WiFi libs don't currently
+           auto-reassociate. */
+        esp_wifi_connect();
+        xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
+        break;
+    default:
+        break;
+    }
+    return ESP_OK;
+}
+
+static void wifi_conn_init(void)
+{
+    tcpip_adapter_init();
+    wifi_event_group = xEventGroupCreate();
+    ESP_ERROR_CHECK( esp_event_loop_init(wifi_event_handler, NULL) );
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
+    ESP_ERROR_CHECK( esp_wifi_set_storage(WIFI_STORAGE_RAM) );
+    wifi_config_t wifi_config = {
+        .sta = {
+            .ssid = EXAMPLE_WIFI_SSID,
+            .password = EXAMPLE_WIFI_PASS,
+        },
+    };
+    ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_STA) );
+    ESP_ERROR_CHECK( esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );
+
+    ESP_ERROR_CHECK( esp_wifi_start() );
+}
+
+void app_main(void)
+{
+    nvs_flash_init();
+    wifi_conn_init();
+}

examples/23_coap_client/main/coap_client.h

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+/* CoAP client Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#ifndef _COAP_CLIENT_H_
+#define _COAP_CLIENT_H_
+
+#include <sdkconfig.h>
+
+/* The examples use simple WiFi configuration that you can set via
+   'make menuconfig'.
+
+   If you'd rather not, just change the below entries to strings with
+   the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
+*/
+#define EXAMPLE_WIFI_SSID            CONFIG_WIFI_SSID
+#define EXAMPLE_WIFI_PASS            CONFIG_WIFI_PASSWORD
+
+#define COAP_DEMO_THREAD_NAME        "CoAP_demo"
+#define COAP_DEMO_THREAD_STACK_WORDS 10240
+#define COAP_DEMO_THREAD_PRORIOTY    8
+
+#define COAP_DEFAULT_TIME_SEC 5
+#define COAP_DEFAULT_TIME_USEC 0
+
+/* The examples use domain of "californium.eclipse.org",uri "coap://californium.eclipse.org" and port number of 5683 that
+   you can set via 'make menuconfig'.
+
+   If you'd rather not, just change the below entries to strings with
+   the config you want - ie #define COAP_DEFAULT_DEMO_ADDR "californium.eclipse.org"
+   , ie #define COAP_DEFAULT_DEMO_URI "coap://californium.eclipse.org" and ie #define COAP_DEFAULT_PORT 5683
+*/
+#define COAP_DEFAULT_PORT CONFIG_TARGET_PORT_NUMBER
+#define COAP_DEFAULT_DEMO_ADDR CONFIG_TARGET_DOMAIN
+#define COAP_DEFAULT_DEMO_URI CONFIG_TARGET_DOMAIN_URI
+
+#endif
+

examples/23_coap_client/main/component.mk

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+#
+# "main" pseudo-component makefile.
+#
+# (Uses default behaviour of compiling all source files in directory, adding 'include' to include path.)
+