前言

1. 实现多个客户端同时连接
2. 初步代码结构已经实现完成(通过轮训的方式)

//
// Created by shchl on 2024/3/8.
//
#if  1

#include <string.h>
#include "lwip/api.h"
#include "FreeRTOS.h"
#include "task.h"
#include "usart.h"
#include "lwip_comm.h"

#define CLIENT_LIST_SIZE 3
typedef struct {
    u8_t stat;/*0表示未连接，1表示已建立连接*/
    struct netconn *conn;
    struct netbuf *net_buf;
    ip_addr_t ip; /*地址*/
    u16_t port;/*端口*/
#define BUF_SIZE 1024
    u8_t buf[BUF_SIZE];/*存放数据*/

} client_pcb;/*客户端控制块*/
static TaskHandle_t tcp_server; /*任务句柄*/
static TaskHandle_t tcp_client; /*任务句柄*/
static void tcp_server_entity(void *args);

client_pcb client_list[CLIENT_LIST_SIZE]; /*客户端列表*/

static void tcp_client_request_entity(void *args);

void netconn_tcp_server_create_thread() {
    /*初始化*/
    memset(client_list, 0, sizeof(client_list));


    xTaskCreate(
            (TaskFunction_t) tcp_server_entity,
            "tcp_server",
            256,
            NULL,
            10,
            &tcp_server
    );

    xTaskCreate(
            (TaskFunction_t) tcp_client_request_entity,
            "tcp_client",
            256,
            NULL,
            9,
            &tcp_client
    );

}

#define TCP_SERVER_RX_BUFSIZE 1500
static struct netconn *conn;
static struct netconn *client_conn;/*客户端连接*/
static uint8_t remot_addr[4] = {0}; /*远端ip数组*/
static u16_t port;/*远端端口*/
static ip_addr_t ipaddr;/*远端ip*/
static u8_t tcp_server_recvbuf[TCP_SERVER_RX_BUFSIZE] = {0};


static void tcp_server_entity(void *args) {
    err_t err;
    conn = netconn_new(NETCONN_TCP);  //创建一个TCP链接
    netconn_bind(conn, IP_ADDR_ANY, 8080);  //绑定端口 8号端口
    netconn_listen(conn);        //进入监听模式
    conn->recv_timeout = 10;    //禁止阻塞线程 等待10ms
    struct netconn *cli_con;

    while (1) {

        begin_listen:
        err = netconn_accept(conn, &cli_con);  //接收连接请求
        if (err == ERR_OK) {

            cli_con->recv_timeout = 10;
            for (int i = 0; i < CLIENT_LIST_SIZE; ++i) {
                if (client_list[i].stat == 0) {

                    netconn_getaddr(cli_con, &client_list[i].ip, &client_list[i].port, 0); //获取远端IP地址和端口号
                    remot_addr[3] = (uint8_t) (client_list[i].ip.addr >> 24);
                    remot_addr[2] = (uint8_t) (client_list[i].ip.addr >> 16);
                    remot_addr[1] = (uint8_t) (client_list[i].ip.addr >> 8);
                    remot_addr[0] = (uint8_t) (client_list[i].ip.addr);
                    printf("主机%d.%d.%d.%d连接上服务器,主机端口号为:%d\r\n",
                           remot_addr[0], remot_addr[1], remot_addr[2], remot_addr[3], client_list[i].port);
                    client_list[i].stat = 1;
                    client_list[i].conn = cli_con;

                    goto begin_listen;
                }
            }
            /*释放链接*/
            netconn_close(cli_con);
            netconn_delete(cli_con);

        }
        vTaskDelay(10);
    }
}


static void tcp_client_request_entity(void *args) {

    client_pcb *p_client;
    err_t err;
    u32_t data_len;
    while (1) {

        for (int i = 0; i < CLIENT_LIST_SIZE; ++i) {
            p_client = &client_list[i];
            if (p_client->stat == 1) {
                err = netconn_recv(p_client->conn, &p_client->net_buf);
                switch (err) {
                    case ERR_OK: {
                        portDISABLE_INTERRUPTS();
                        memset(p_client->buf, 0, BUF_SIZE);  //数据接收缓冲区清零
                        for (struct pbuf *q = p_client->net_buf->p; q != NULL; q = q->next)  //遍历完整个pbuf链表
                        {
                            if (q->len > (BUF_SIZE - data_len)) {
                                /*数据超出缓冲区大小*/
                                memcpy(p_client->buf + data_len, q->payload, BUF_SIZE - data_len);
                                break;
                            } else {
                                memcpy(p_client->buf + data_len, q->payload, q->len);
                            }
                            data_len += q->len;
                            if (data_len > BUF_SIZE) break;
                        }
                        portENABLE_INTERRUPTS();
                        // todo 应用逻辑处理
                        netconn_write(p_client->conn, p_client->buf, data_len, NETCONN_COPY);
                        data_len = 0;  //复制完成后data_len要清零。
                        netbuf_delete(p_client->net_buf);
                        break;
                    }
                    case ERR_CLSD:
                    case ERR_RST: {
                        goto release_conn_tag;
                    }
                    default:
                        if (g_lwipdev.link_status == LWIP_LINK_OFF) { /*判断网线是否连接正常*/
                            printf("物理连线出现问题\r\n");
                            goto release_conn_tag;
                        }

                }
                continue;
                release_conn_tag: /*释放链接*/
                {
                    netconn_close(p_client->conn);
                    netconn_delete(p_client->conn);
                    p_client->stat = 0;
                }
            }
            vTaskDelay(10);
        }


    }


}

#endif

测试结果