Lwip之TCP客户端示例记录

前言

1. 使用两个线程作为客户端中的收和发
2. 使用线程挂起和线程恢复的api来实现
3. 接收线程必须要保证在处理连接状态才能进行接收。

Demo

//
// Created by shchl on 2024/3/8.
//
#include <string.h>
#include "lwip/api.h"
#include "FreeRTOS.h"
#include "task.h"

#define TCP_CLIENT_RX_BUFSIZE 256

static void tcp_client_send(void *);

static void tcp_client_rec(void *);

static TaskHandle_t client_send_handle;
static TaskHandle_t client_rec_handle;
static ip_addr_t server_ipaddr, loca_ipaddr;
static uint16_t server_port = 8080;
static struct netconn *tcp_conn;
static uint8_t tcp_client_recvbuf[TCP_CLIENT_RX_BUFSIZE] = {0};    //TCP客户端接收数据缓冲区


void create_netconn_tcp_client_thread() {

    xTaskCreate((TaskFunction_t) tcp_client_send,
                (const char *) "tcp_client_send",
                (uint16_t) 256,
                (void *) NULL,
                (UBaseType_t) 10,
                (TaskHandle_t *) &client_send_handle);

    xTaskCreate((TaskFunction_t) tcp_client_rec,
                (const char *) "tcp_client_rec",
                (uint16_t) 256,
                (void *) NULL,
                (UBaseType_t) 11,
                (TaskHandle_t *) &client_rec_handle);

}

const char *tcp_client_sendbuf = "Apollo STM32F4/F7 NETCONN TCP Client send data\r\n";    //TCP客户端发送数据缓冲区
static void tcp_client_send(void *arg) {
    err_t err, recv_err;
    IP4_ADDR(&server_ipaddr, 192, 168, 8, 2);
    while (1) {

        tcp_conn = netconn_new(NETCONN_TCP);  //创建一个TCP链接
        err = netconn_connect(tcp_conn, &server_ipaddr, server_port);//连接服务器
        if (err != ERR_OK) {
            netconn_delete(tcp_conn); //返回值不等于ERR_OK,删除tcp_clientconn连接
            printf("连接失败....等待重新连接\r\n");
            vTaskDelay(1000);
            continue;
        } else {
            vTaskResume(client_rec_handle);/*恢复接收线程*/
            printf("连接...ok\r\n");
        }
        while (1) {
            err = netconn_write(tcp_conn, tcp_client_sendbuf, strlen((char *) tcp_client_sendbuf),
                                NETCONN_COPY); //发送tcp_server_sentbuf中的数据
            if (err != ERR_OK) {
                printf("发送失败\r\n");
                netconn_close(tcp_conn);
                netconn_delete(tcp_conn);
                break;
            }
            vTaskDelay(1000);
        }
    }
}

static void tcp_client_rec(void *arg) {
    err_t recv_err;
    uint32_t data_len;
    struct pbuf *q;
    struct netbuf *recvbuf;
    vTaskSuspend(client_rec_handle); /*挂起自身线程*/
    while (1) {
        if ((recv_err = netconn_recv(tcp_conn, &recvbuf)) == ERR_OK)  //接收到数据
        {
            portDISABLE_INTERRUPTS(); //关中断
            memset(tcp_client_recvbuf, 0, TCP_CLIENT_RX_BUFSIZE);  //数据接收缓冲区清零
            for (q = recvbuf->p; q != NULL; q = q->next)  //遍历完整个pbuf链表
            {
                //判断要拷贝到TCP_CLIENT_RX_BUFSIZE中的数据是否大于TCP_CLIENT_RX_BUFSIZE的剩余空间，如果大于
                //的话就只拷贝TCP_CLIENT_RX_BUFSIZE中剩余长度的数据，否则的话就拷贝所有的数据
                if (q->len > (TCP_CLIENT_RX_BUFSIZE - data_len))
                    memcpy(tcp_client_recvbuf + data_len, q->payload, (TCP_CLIENT_RX_BUFSIZE - data_len));//拷贝数据
                else memcpy(tcp_client_recvbuf + data_len, q->payload, q->len);
                data_len += q->len;
                if (data_len > TCP_CLIENT_RX_BUFSIZE) break; //超出TCP客户端接收数组,跳出
            }
            portENABLE_INTERRUPTS(); //关中断
            data_len = 0;  //复制完成后data_len要清零。
            printf("%s", tcp_client_recvbuf);
            netbuf_delete(recvbuf);
        } else if (recv_err == ERR_CLSD)  //关闭连接
        {
            printf("服务器%d.%d.%d.%d断开连接\r\n", 192, 168, 8, 2);
            vTaskSuspend(client_rec_handle); /*挂起自身线程*/
        }

    }
}
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