RT-Thread-lwip socket重新连接无法连接问题？RT-Thread问答社区

lwip socket重新连接无法连接问题？

发布于 2024-04-22 15:58:22 浏览：842 订阅该版

[tocm]

# 一、基础描述
硬件没有问题，此前得方案是freertos+lwip+socket，服务端能够满足多客户端得连接
目前改为使用RTT-STUDIO。
# 二、现象
板子作为服务端使用，电脑助手模拟客户端，目前多客户端连接没有问题。但是客户端断开某个连接之后再次连接无法连接上，等待几分钟不等的时间就能连接上了。如果是新的客户端（即端口号发生了变化）立马能连的上。使用如下图所示助手，
![捕获.JPG](https://oss-club.rt-thread.org/uploads/20240422/0ff78d355adf40bc1506e759e89edd9a.jpg.webp)
三、代码
代码中一些setsockopt函数均为尝试设置wait time等做出修改，结果都是无效。
```c
void free_mem_task(char number)
{
      if (tcp_remote_clientad.state[number])
      {
            printf("--%d# connected is del\r\n", tcp_remote_clientad.state[number]);
            if (tcp_remote_clientad.state[number] != 0)
            {
                  // setsockopt(tcp_remote_clientad.state[number], SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int));
                  if (closesocket(tcp_remote_clientad.state[number]) == 0)
                  {
                        printf("close socket success\r\n");
                  }
                  // shutdown(tcp_remote_clientad.state[number],SHUT_RDWR  );
            }

// tcp_remote_clientad.connected_num--;

tcp_remote_clientad.state[number] = 0;                               // 将该序号的连接清零
            rt_thread_delete(tcp_remote_clientad.Client_RX_Task_Handle[number]); // 删除AppTaskCreate任务

// printf("--tcp_tx_%d memory is free     \r\n",number);
            rt_thread_delete(tcp_remote_clientad.Client_TX_Task_Handle[number]); // 删除AppTaskCreate任务
                                                                                 // xSemaphoreTake(Semaphore_TX[number], 0);                 //将删除的任务等待的信号量清零

if (tcp_remote_clientad.rx_data[number])
                  rt_free(tcp_remote_clientad.rx_data[number]);
            if (tcp_remote_clientad.tx_data[number])
                  rt_free(tcp_remote_clientad.tx_data[number]);
      }
}
// 客户端删除任务
void client_del_Task(void *parameter)
{
      // BaseType_t xResult;
      char num;
      uint32_t client_task_id = 0;
      while (1)
      {
            if (rt_mb_recv(&mb_1, &client_task_id, RT_WAITING_FOREVER) == RT_EOK)
            {
                  rt_kprintf("client delete task: get a mail from mailbox, the content:%d\n", client_task_id);
                  free_mem_task(client_task_id);
            }
            rt_thread_mdelay(100);
      }
}
```
```c
void tcpserv(void *parameter)
{
      char *recv_data; /* 用于接收的指针，后面会做一次动态分配以请求可用内存 */
      socklen_t sin_size;
      int connected, bytes_received;
      struct sockaddr_in server_addr, client_addr;
      rt_bool_t stop = RT_FALSE; /* 停止标志 */
      int ret;
      recv_data = rt_malloc(BUFSZ + 1); /* 分配接收用的数据缓冲 */
      if (recv_data == RT_NULL)
      {
            rt_kprintf("No memory\n");
            return;
      }
      rt_kprintf("tcp server task start\r\n");
      /* 一个socket在使用前，需要预先创建出来，指定SOCK_STREAM为TCP的socket */
      if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
      {
            /* 创建失败的错误处理 */
            rt_kprintf("Socket error\n");
            /* 释放已分配的接收缓冲 */
            rt_free(recv_data);
            return;
      }

struct linger opt = {1, 10};
      if (setsockopt(sock, SOL_SOCKET, SO_LINGER, &opt, sizeof(opt)) != 0)
      {
            rt_kprintf("so_linger set ok \n");
      }

if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) != 0)
      {
            rt_kprintf("SO_REUSEADDR set ok \n");
      }
       char bDontLinger = 0;
      setsockopt(sock, SOL_SOCKET, SO_DONTLINGER, (const char *)&bDontLinger, sizeof(char));
      /* 初始化服务端地址 */
      server_addr.sin_family = AF_INET;
      server_addr.sin_port = htons(8123); /* 服务端工作的端口 */
      server_addr.sin_addr.s_addr = INADDR_ANY;
      rt_memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero));
      /* 绑定socket到服务端地址 */
      if (bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
      {
            /* 绑定失败 */
            rt_kprintf("Unable to bind\n");
            /* 释放已分配的接收缓冲 */
            rt_free(recv_data);
            return;
      }
      /* 在socket上进行监听 */
      if (listen(sock, 5) == -1)
      {
            rt_kprintf("Listen error\n");
            /* release recv buffer */
            rt_free(recv_data);
            return;
      }
      // 将socket设置为非阻塞模式
      // int flags = fcntl(sock, F_GETFL, 0);
      // fcntl(sock, F_SETFL, flags | O_NONBLOCK);

rt_kprintf("\nTCPServer Waiting for client on port 5000...\n");
      create_tcp_remote_client_close_task(); // 创建远端客户端删除任务
      while (stop != RT_TRUE)
      {
            uint32_t client_task_id;
            // if (rt_mb_recv(&mb_1, &client_task_id, 100) == RT_EOK)
            // {
            //       rt_kprintf("client delete task: get a mail from mailbox, the content:%d\n", client_task_id);
            //       free_mem_task(client_task_id);
            // }
            rt_kprintf("tcp server task run\r\n");
            sin_size = sizeof(struct sockaddr_in);
            /* 接受一个客户端连接socket的请求，这个函数调用是阻塞式的 */
            connected = accept(sock, (struct sockaddr *)&client_addr, &sin_size);
            /* 返回的是连接成功的socket */
            if (connected < 0)
            {
                  rt_kprintf("accept connection failed! errno = %d\n", errno);
                  rt_thread_mdelay(100);
                  continue;
            }
            /* 接受返回的client_addr指向了客户端的地址信息 */
            rt_kprintf("new connection from (%s , %d)\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

// 不等待 TIME_WAIT 时间的情况下立即关闭 socket。
            // struct linger opt = {1, 10};
           // setsockopt(connected, SOL_SOCKET, SO_LINGER, &opt, sizeof(opt));

if (setsockopt(connected, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) != 0)
            {
                  rt_kprintf("connected SO_REUSEADDR set ok \n");
            }
           
            setsockopt(connected, SOL_SOCKET, SO_DONTLINGER, (const char *)&bDontLinger, sizeof(char));

int flag = 1; // 设置TCP相关

flag = 1; // 设置keepalive
                      // setsockopt(connected, SOL_SOCKET, SO_KEEPALIVE, &flag, sizeof(int));

create_tcp_remote_client_thread(connected);
            rt_thread_mdelay(10);
	  }
	
	
	
```