写一个stm32以太网的客户端和服务器函数

这里提供一个简单的STM32以太网客户端和服务器函数的示例，使用的是HAL库以及lwIP协议栈。需要注意的是，这只是一个简单的示例，实际使用时需要根据具体情况进行修改和完善。

客户端：

#include "lwip/opt.h"
#include "lwip/arch.h"
#include "lwip/api.h"
#include "lwip/api_msg.h"
#include "lwip/err.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/tcpip.h"
#include "lwip/timeouts.h"

#define SERVER_IP_ADDR "192.168.1.100"
#define SERVER_PORT 5000

void client_task(void* arg) {
  struct netconn *conn;
  err_t err;
  struct netbuf *buf;

  /* 创建TCP连接 */
  conn = netconn_new(NETCONN_TCP);
  if (conn == NULL) {
    printf("Failed to create TCP connection\n");
    return;
  }

  /* 连接服务器 */
  err = netconn_connect(conn, IP_ADDR_ANY, SERVER_PORT);
  if (err != ERR_OK) {
    printf("Failed to connect to server\n");
    netconn_delete(conn);
    return;
  }

  /* 发送数据 */
  char *data = "Hello, server!";
  err = netconn_write(conn, data, strlen(data), NETCONN_COPY);
  if (err != ERR_OK) {
    printf("Failed to send data\n");
    netconn_close(conn);
    netconn_delete(conn);
    return;
  }

  /* 接收数据 */
  err = netconn_recv(conn, &buf);
  if (err == ERR_OK) {
    printf("Received data: ");
    while (buf != NULL) {
      char *data = netbuf_alloc(buf, sizeof(char));
      if (data != NULL) {
        netbuf_copy(buf, data, sizeof(char));
        printf("%c", *data);
      }
      netbuf_next(buf);
    }
    printf("\n");
  } else {
    printf("Failed to receive data\n");
  }

  /* 关闭连接 */
  netconn_close(conn);
  netconn_delete(conn);
}

int main() {
  /* 初始化lwIP协议栈 */
  tcpip_init(NULL, NULL);

  /* 创建客户端任务 */
  sys_thread_new("client", client_task, NULL, 1024, 1);

  /* 启动lwIP协议栈 */
  while (1) {
    sys_check_timeouts();
  }
}

服务器：

#include "lwip/opt.h"
#include "lwip/arch.h"
#include "lwip/api.h"
#include "lwip/api_msg.h"
#include "lwip/err.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/tcpip.h"
#include "lwip/timeouts.h"

#define SERVER_PORT 5000

void server_task(void* arg) {
  struct netconn *conn, *newconn;
  err_t err;

  /* 创建TCP监听 */
  conn = netconn_new(NETCONN_TCP);
  if (conn == NULL) {
    printf("Failed to create TCP connection\n");
    return;
  }

  /* 绑定端口 */
  err = netconn_bind(conn, IP_ADDR_ANY, SERVER_PORT);
  if (err != ERR_OK) {
    printf("Failed to bind to port %d\n", SERVER_PORT);
    netconn_delete(conn);
    return;
  }

  /* 开始监听 */
  err = netconn_listen(conn);
  if (err != ERR_OK) {
    printf("Failed to listen on port %d\n", SERVER_PORT);
    netconn_delete(conn);
    return;
  }

  while (1) {
    /* 接受新连接 */
    err = netconn_accept(conn, &newconn);
    if (err != ERR_OK) {
      printf("Failed to accept connection\n");
      continue;
    }

    /* 接收数据 */
    struct netbuf *buf;
    err = netconn_recv(newconn, &buf);
    if (err == ERR_OK) {
      printf("Received data: ");
      while (buf != NULL) {
        char *data = netbuf_alloc(buf, sizeof(char));
        if (data != NULL) {
          netbuf_copy(buf, data, sizeof(char));
          printf("%c", *data);
        }
        netbuf_next(buf);
      }
      printf("\n");

      /* 发送回复 */
      char *reply = "Hello, client!";
      err = netconn_write(newconn, reply, strlen(reply), NETCONN_COPY);
      if (err != ERR_OK) {
        printf("Failed to send reply\n");
      }
    } else {
      printf("Failed to receive data\n");
    }

    /* 关闭连接 */
    netconn_close(newconn);
    netconn_delete(newconn);
  }
}

int main() {
  /* 初始化lwIP协议栈 */
  tcpip_init(NULL, NULL);

  /* 创建服务器任务 */
  sys_thread_new("server", server_task, NULL, 1024, 1);

  /* 启动lwIP协议栈 */
  while (1) {
    sys_check_timeouts();
  }
}