w5500用sock怎么试，组播功能都不行

发布于 2022-05-10 17:02:19 浏览：643 订阅该版

```c
  /* 创建一个socket，类型是SOCK_DGRAM，UDP类型 */
    if ((sock_group = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
    {
        rt_kprintf("Socket error\n");

/* 释放接收用的数据缓冲 */
        rt_free(recv_data);
        return;
    }

memset(&server_addr,0,sizeof(server_addr));
     /* 初始化服务端地址 */
      server_addr.sin_family = AF_INET;
      server_addr.sin_port = htons(37889);
      server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
       if (bind(sock_group, (struct sockaddr *)&server_addr,
             sizeof(struct sockaddr)) == -1)
    {
        /* 绑定地址失败 */
        rt_kprintf("Bind error\n");

/* 释放接收用的数据缓冲 */
        rt_free(recv_data);
        return;
    }

struct ip_mreq ipmr;

ipmr.imr_interface.s_addr = htonl(INADDR_ANY);
    ipmr.imr_multiaddr.s_addr = inet_addr("239.255.255.250");

int loop=1;

if(-1==setsockopt(sock_group, IPPROTO_IP, IP_MULTICAST_LOOP,& loop, sizeof(loop)))
    {
        rt_kprintf("IPPROTO_IP, IP_MULTICAST_LOOP");
    }

if(setsockopt(sock_group, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&ipmr, sizeof(ipmr)))
    {

rt_kprintf("IP_ADD_MEMBERSHIP\r\n");
        return;
    }
    else {
        rt_kprintf("IP_ADD_MEMBERSHIP OK!\r\n");
    }
      
       addr_len = sizeof(struct sockaddr);
    rt_kprintf("UDPServer_group Waiting for client on port 37889...\n");

while (1)
    {
        /* 从sock中收取最大BUFSZ - 1字节数据 */
        bytes_read = recvfrom(sock_group, recv_data, BUFSZ - 1, 0,
                              (struct sockaddr *)&client_addr, &addr_len);
        /* UDP不同于TCP，它基本不会出现收取的数据失败的情况，除非设置了超时等待 */

recv_data[bytes_read] = '\0'; /* 把末端清零 */
           rt_kprintf("%s", recv_data);

}
      
```