esp32 tcp client的使用

一、esp32 tcp 客户端使用步骤

1、创建一个套接字描述符 使用socket(AF_INET, SOCK_STREAM ,0)函数

2、设置本地端口等   使用bind(tcpsock,(struct sockaddr *)&Loacl_addr,sizeof(Loacl_addr));

3、连接server    使用connect(tcpsock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));

4、发送数据    使用send(tcpsock, "tcp test", strlen("tcp test"), 0);

5、接收服务器的数据  使用recv(tcpsock, rx_buffer, sizeof(rx_buffer) - 1, 0);

 

二、详细代码

#include 
#include 
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "tcpip_adapter.h"

#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include 


#define HOST_IP_ADDR "192.168.43.95"
#define PORT         12345
int tcpsock = 0;
struct sockaddr_in dest_addr;
 TaskHandle_t xtcpRecvTask = NULL;

void tcp_recv_data(void *pvParameters){

    uint8_t rx_buffer[1024] = {0};
    printf("create tcp recv\n");
        int err = send(tcpsock, "tcp test", strlen("tcp test"), 0);
    if (err < 0) {
        printf( "Error occurred during sending: errno %d", errno);
        return;
        }
        printf("Message sent");

   
    while (1)
    {
        int len = recv(tcpsock, rx_buffer, sizeof(rx_buffer) - 1, 0);
        if(len > 0){
                rx_buffer[len] = 0; // Null-terminate whatever we received and treat like a string
                printf("Received %d bytes from %s:\n", len, rx_buffer);
          
                int err = send(tcpsock, rx_buffer, len, 0);
                if (err < 0) {
                    printf( "Error occurred during sending: errno %d", errno);
                    return;
                 }
                 printf("Message sent");
        }
    }

}

void tcp_ini_client(void){

    tcpsock = socket(AF_INET, SOCK_STREAM ,0);
     printf("sock:%d\n",tcpsock);
    if(tcpsock < 0){
        
       printf( "Unable to create socket: errno %d", errno);
       return;
    }
    printf("Socket created, sending to %s:%d", HOST_IP_ADDR, PORT);
   
    dest_addr.sin_addr.s_addr = inet_addr(HOST_IP_ADDR);
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(PORT);
    struct sockaddr_in Loacl_addr;  //设置本地端口
    Loacl_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    Loacl_addr.sin_family = AF_INET;
    Loacl_addr.sin_port = htons(54321);
    uint8_t res = 0;
    res = bind(tcpsock,(struct sockaddr *)&Loacl_addr,sizeof(Loacl_addr));
    if(res != 0){
        printf("bind error\n");

    }
    int err = connect(tcpsock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
    if (err != 0) {
            printf( "Socket unable to connect: errno %d", errno);
            return;
        }
    printf( "Successfully connected\n");
    xTaskCreate(&tcp_recv_data,"tcp_recv_data",2048*2,NULL,10,&xtcpRecvTask);
    }

  

三、测试结果

流程和UDP 的是一样的 开始client发送一个字符串 然后等待接收服务器的数据并且把接收到的数据原路返回