tcp_client example: support for Linux target.

examples/protocols/sockets/tcp_client/main/tcp_client_v4.c

@@ -0,0 +1,92 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include "sdkconfig.h"
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <netdb.h>            // struct addrinfo
+#include <arpa/inet.h>
+#include "esp_netif.h"
+#include "esp_log.h"
+#if defined(CONFIG_EXAMPLE_SOCKET_IP_INPUT_STDIN)
+#include "addr_from_stdin.h"
+#endif
+
+#if defined(CONFIG_EXAMPLE_IPV4)
+#define HOST_IP_ADDR CONFIG_EXAMPLE_IPV4_ADDR
+#elif defined(CONFIG_EXAMPLE_SOCKET_IP_INPUT_STDIN)
+#define HOST_IP_ADDR ""
+#endif
+
+#define PORT CONFIG_EXAMPLE_PORT
+
+static const char *TAG = "example";
+static const char *payload = "Message from ESP32 ";
+
+
+void tcp_client(void)
+{
+    char rx_buffer[128];
+    char host_ip[] = HOST_IP_ADDR;
+    int addr_family = 0;
+    int ip_protocol = 0;
+
+    while (1) {
+#if defined(CONFIG_EXAMPLE_IPV4)
+        struct sockaddr_in dest_addr;
+        inet_pton(AF_INET, host_ip, &dest_addr.sin_addr);
+        dest_addr.sin_family = AF_INET;
+        dest_addr.sin_port = htons(PORT);
+        addr_family = AF_INET;
+        ip_protocol = IPPROTO_IP;
+#elif defined(CONFIG_EXAMPLE_SOCKET_IP_INPUT_STDIN)
+        struct sockaddr_storage dest_addr = { 0 };
+        ESP_ERROR_CHECK(get_addr_from_stdin(PORT, SOCK_STREAM, &ip_protocol, &addr_family, &dest_addr));
+#endif
+
+        int sock =  socket(addr_family, SOCK_STREAM, ip_protocol);
+        if (sock < 0) {
+            ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
+            break;
+        }
+        ESP_LOGI(TAG, "Socket created, connecting to %s:%d", host_ip, PORT);
+
+        int err = connect(sock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
+        if (err != 0) {
+            ESP_LOGE(TAG, "Socket unable to connect: errno %d", errno);
+            break;
+        }
+        ESP_LOGI(TAG, "Successfully connected");
+
+        while (1) {
+            int err = send(sock, payload, strlen(payload), 0);
+            if (err < 0) {
+                ESP_LOGE(TAG, "Error occurred during sending: errno %d", errno);
+                break;
+            }
+
+            int len = recv(sock, rx_buffer, sizeof(rx_buffer) - 1, 0);
+            // Error occurred during receiving
+            if (len < 0) {
+                ESP_LOGE(TAG, "recv failed: errno %d", errno);
+                break;
+            }
+            // Data received
+            else {
+                rx_buffer[len] = 0; // Null-terminate whatever we received and treat like a string
+                ESP_LOGI(TAG, "Received %d bytes from %s:", len, host_ip);
+                ESP_LOGI(TAG, "%s", rx_buffer);
+            }
+        }
+
+        if (sock != -1) {
+            ESP_LOGE(TAG, "Shutting down socket and restarting...");
+            shutdown(sock, 0);
+            close(sock);
+        }
+    }
+}