c - 我试图通过 ioctl 从驱动程序获得的以太网速度是恒定的，比如 57872Mbps，为什么？

Question

我正在尝试读取我设备上的以太网速度，尽管我正在连接 100mbps 电缆，但它的读数始终为相同的常数值 57872 或一些垃圾值或 0....我做的程序逻辑如下它不会包含所有代码只有它的一部分:

void get_link_config_res(void)
{
    int i=0;
    FILE *fp;
    int ret_val;
    char in_buf[200];
    char in_buf1[64];

    unsigned char interface_name[10];
    int sock_id;
    struct ifreq ir;
    struct sockaddr_in *sin = (void *) &ir.ifr_ifru.ifru_addr;
    struct sockaddr_in *nmsk = (void *) &ir.ifr_ifru.ifru_netmask;
    //struct sockaddr_in *brdcast = (void *) &ir.ifr_ifru.ifru_broadaddr;
    static int_net_cfg_t int_eth,int_wifi;
    int_netcfg_array_t temp_netcfg,wifi_netcfg;

    static __u8 mac_address[6];
    char *temp_buf;
    struct ethtool_cmd edata;

    if(verify_host_link_status(ETH_0) == SET_FLAG)
    {
        /* get Ethernet link status */
        memset(&ir, 0, sizeof(ir));
        memset(in_buf, 0, sizeof(in_buf));
        memset(in_buf1, 0, sizeof(in_buf1));
        memset(mac_address, 0, sizeof(mac_address));
        memset(interface_name, 0, sizeof(interface_name));

        strcpy(ir.ifr_name, ETHERNET);


        /* socket creation (IPV4) */
        sock_id = socket(AF_INET, SOCK_DGRAM, 0);
        if(sock_id < 0)
        {
            SPX_DEBUG_3("cannot open socket \n");
        }

        strcpy(ir.ifr_ifrn.ifrn_name, ir.ifr_name);

        ir.ifr_data = (char *)&edata;
        //printf("Ethernet speed 1=",ir.ifr_data);
        ret_val = ioctl(sock_id, SIOCGIFHWADDR, &ir);
        //printf("retval of ioctl is = %d\n",ret_val);
        memcpy(mac_address, &ir.ifr_ifru.ifru_hwaddr.sa_data, 6);

        for(i=0; i<6; i++)
        {
            temp_netcfg.hwaddr[i] = mac_address[i];
        }
        mac2string(temp_netcfg.hwaddr, &in_buf1);

        sprintf(in_buf,"echo mac_address=%s > %s", in_buf1, ETHERNET_PARAMS_FILE);
        system(in_buf);

        edata.cmd = ETHTOOL_GSET;
        /*eth speed*/
        ret_val = ioctl(sock_id, SIOCETHTOOL, &ir);
        memset(in_buf, 0, sizeof(in_buf));
        //printf("Ethernet speed=%d",edata.speed);
        switch (edata.speed)
        {
            case SPEED_10:
                sprintf(in_buf,"echo speed=10Mbps >> %s",ETHERNET_PARAMS_FILE);
                system(in_buf);
                //printf("10Mbps\n");
                break;
            case SPEED_100:
                //printf("100Mbps\n");
                sprintf(in_buf,"echo speed=100Mbps >> %s",ETHERNET_PARAMS_FILE);
                system(in_buf);
                break;
            case SPEED_1000:
                //printf("1Gbps\n");
                sprintf(in_buf,"echo speed=1Gbps >> %s",ETHERNET_PARAMS_FILE);
                system(in_buf);
                break;
            case SPEED_10000:
                //printf("10Gbps\n");
                sprintf(in_buf,"echo speed=10Gbps >> %s",ETHERNET_PARAMS_FILE);
                system(in_buf);
                break;
            default:
                //printf("Speed returned is ____%d\n", edata.speed);
                sprintf(in_buf,"echo speed=%dMbps >> %s",edata.speed, ETHERNET_PARAMS_FILE);
                system(in_buf);
                break;
        }

        memset(in_buf, 0, sizeof(in_buf));

        /* get the IP address */
        ret_val = ioctl(sock_id, SIOCGIFADDR, &ir);
        int_eth.ipaddr.s_addr = sin->sin_addr.s_addr;
        /*To get Ip address in ASCII format*/
        temp_buf = inet_ntoa(int_eth.ipaddr);
        strcpy (in_buf, temp_buf);
        sprintf(in_buf,"echo ip_address=%s >> %s",temp_buf, ETHERNET_PARAMS_FILE);
        system(in_buf);

        memset(in_buf, 0, sizeof(in_buf));
         /*subnet mask*/
        ret_val = ioctl(sock_id, SIOCGIFNETMASK, &ir);
        int_eth.netmask.s_addr = nmsk->sin_addr.s_addr;

        /*To get subnet mask in ASCII format*/
        temp_buf = inet_ntoa(int_eth.netmask);
        strcpy (in_buf, temp_buf);
        sprintf(in_buf,"echo subnet_mask=%s >> %s",temp_buf, ETHERNET_PARAMS_FILE);
        system(in_buf);
        close(sock_id);
    }
    else
    {
        /*Host is not connected, to the  Ethernet interface.*/
        //printf("Ethernet Interface is not connected...\n");
        memset(in_buf1, 0, sizeof(in_buf1));
        strcpy(in_buf1, "NONE");
        sprintf(in_buf,"echo mac_address=%s > %s", in_buf1, ETHERNET_PARAMS_FILE);
        system(in_buf);

        sprintf(in_buf,"echo speed=%s >> %s", in_buf1, ETHERNET_PARAMS_FILE);
        system(in_buf);

        sprintf(in_buf,"echo ip_address=%s >> %s",in_buf1, ETHERNET_PARAMS_FILE);
        system(in_buf);

        sprintf(in_buf,"echo subnet_mask=%s >> %s",in_buf1, ETHERNET_PARAMS_FILE);
        system(in_buf);
        //status = CLEAR_FLAG;
    }
}

请帮我解决这个问题......提前致谢......

Answer 1

ret_val = ioctl(sock_id, SIOCETHTOOL, &ir);

至少，你一半了。您似乎认识到 ioctl 可能会失败这一事实，但您没有执行并实际检查返回值。

鉴于您的文本表明该值总是是错误的(“57872 或一些垃圾值或总是 0”)，我敢打赌您会返回一个一致的错误代码，例如 EOPNOTSUPP。

修改代码以先检查，然后再次运行。