求助：多播返回设置正常而多播组加入错误

zu_xf

我用的2.4.25内核，已经使能了IP:multicasting选项。
IP_ADD_MEMBERSHIP多播组加入报错，No such device。
下面是socket创建函数：
int udpSocket(unsigned short int port_no,unsigned long net_ip)
{   
    int local_socket,optval,fd_status,mc_loop;
    struct sockaddr_in addr;
    struct ip_mreq mc_request;
       
    if((local_socket = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    {
        printf("udp socket create error,port no is %d\n",(int)port_no);
        return -1;
    }

        /* 调用bind之前，设置套接口选项启用多播IP支持*/
        mc_loop = 1;
        if(setsockopt(local_socket,SOL_SOCKET, SO_REUSEADDR,&mc_loop, sizeof(mc_ loop)) < 0)
        {
                perror("setsockopt:SO_REUSEADDR");
                exit(EXIT_FAILURE);
        }

    bzero((char *)&addr,sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(net_ip);
    addr.sin_port = htons(port_no);
       
    if(bind(local_socket,(struct sockaddr *)&addr,sizeof(addr)) < 0)
    {
        close(local_socket);
        printf("udp socket bind error,port no is %d\n",(int)port_no);
        return -1;
    }
   
    fd_status = fcntl(local_socket,F_GETFL,0);
    fcntl(local_socket,F_SETFL,fd_status|O_NONBLOCK);       
       
        mc_loop = 1;
        if(setsockopt(local_socket,IPPROTO_IP, IP_MULTICAST_LOOP,&mc_loop, sizeof(mc_loop)) < 0)
        {
                perror("setsockopt:IP_MULTICAST_LOOP");
                exit(EXIT_FAILURE);
        }

        mc_request.imr_multiaddr.s_addr = inet_addr("239.255.255.1");
        mc_request.imr_interface.s_addr = htonl(INADDR_ANY);
        int ret=0;
        if ((ret=setsockopt(local_socket, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mc_request, sizeof(mc_request))) < 0)
        {
                perror("setsockopt:IP_ADD_MEMBERSHIP");
                printf("IP_ADD_MEMBERSHIP:%d\n",ret);

                  /*在此处报错No such device*/

                exit(EXIT_FAILURE);
        }
        *sock_addr = addr;
    return local_socket;
}