c++ - 如何获取ethtool设置？

Question

请帮我获取 ethtool 设置(速度、双工、自动)。

如果我使用 ETHTOOL_GSET，我会得到 ethtool 设置。但是在 ethtool.h 中写入使用 ETHTOOL_GLINKSETTINGS 而不是 ETHTOOL_GSET。我不知道如何使用 ETHTOOL_GLINKSETTINGS。

ETHTOOL_GSET

#include <stdio.h>
#include <string.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>

int main()
{
    int s; // socket
    int r; // result

    struct ifreq ifReq;
    strncpy(ifReq.ifr_name, "enp3s0", sizeof(ifReq.ifr_name));

    struct ethtool_cmd ethtoolCmd;
    ethtoolCmd.cmd = ETHTOOL_GSET;
    ifReq.ifr_data = &ethtoolCmd;

    s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s != -1)
    {
        r = ioctl(s, SIOCETHTOOL, &ifReq);
        if (s != -1)
        {
            printf("%s | ethtool_cmd.speed = %i \n", ifReq.ifr_name, ethtoolCmd.speed);
            printf("%s | ethtool_cmd.duplex = %i \n", ifReq.ifr_name, ethtoolCmd.duplex);
            printf("%s | ethtool_cmd.autoneg = %i \n", ifReq.ifr_name, ethtoolCmd.autoneg);
        }
        else
            printf("Error #r");

        close(s);
    }
    else
        printf("Error #s");

    return 0;
}

结果:

enp3s0 | ethtool_cmd.speed = 1000 
enp3s0 | ethtool_cmd.duplex = 1
enp3s0 | ethtool_cmd.autoneg = 1

ETHTOOL_GLINKSETTINGS

#include <stdio.h>
#include <string.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>

int main()
{
    int s; // socket
    int r; // result

    struct ifreq ifReq;
    strncpy(ifReq.ifr_name, "enp3s0", sizeof(ifReq.ifr_name));

    struct ethtool_link_settings ethtoolLinkSettings;
    ethtoolLinkSettings.cmd = ETHTOOL_GLINKSETTINGS;
    ifReq.ifr_data = &ethtoolLinkSettings;

    s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s != -1)
    {
        r = ioctl(s, SIOCETHTOOL, &ifReq);
        if (s != -1)
        {
            printf("%s | ethtool_link_settings.speed = %i \n", ifReq.ifr_name, ethtoolLinkSettings.speed);
            printf("%s | ethtool_link_settings.duplex = %i \n", ifReq.ifr_name, ethtoolLinkSettings.duplex);
            printf("%s | ethtool_link_settings.autoneg = %i \n", ifReq.ifr_name, ethtoolLinkSettings.autoneg);
        }
        else
            printf("Error #r");

        close(s);
    }
    else
        printf("Error #s");

    return 0;
}

结果:

enp3s0 | ethtool_link_settings.speed = 0 
enp3s0 | ethtool_link_settings.duplex = 45
enp3s0 | ethtool_link_settings.autoneg = 0

为什么 ETHTOOL_GLINKSETTINGS 返回不正确的值？有什么问题？

Answer 1

肯定是这段代码有问题

r = ioctl(s, SIOCETHTOOL, &ifReq);
    if (s != -1)

如何修复此问题并不能解决问题，并且无法使用 ETHTOOL_GLINKSETTINGS 查询接口(interface)属性。看一下头文件就可以看出这一点。

from /usr/include/linux/ethtool.h 

1532 /**                                                                             
1533  * struct ethtool_link_settings - link control and status                       
1534  *                                                                              
1535  * IMPORTANT, Backward compatibility notice: When implementing new              
1536  *  user-space tools, please first try %ETHTOOL_GLINKSETTINGS, and              
1537  *  if it succeeds use %ETHTOOL_SLINKSETTINGS to change link                    
1538  *  settings; do not use %ETHTOOL_SSET if %ETHTOOL_GLINKSETTINGS                
1539  *  succeeded: stick to %ETHTOOL_GLINKSETTINGS/%SLINKSETTINGS in                
1540  *  that case.  Conversely, if %ETHTOOL_GLINKSETTINGS fails, use                
1541  *  %ETHTOOL_GSET to query and %ETHTOOL_SSET to change link                     
1542  *  settings; do not use %ETHTOOL_SLINKSETTINGS if                              
1543  *  %ETHTOOL_GLINKSETTINGS failed: stick to                                     
1544  *  %ETHTOOL_GSET/%ETHTOOL_SSET in that case.       

我确实看到了与报告相同的行为，并观察到使用 ETHTOOL_GSET

报告的正确值

使用 ETHTOOL_GSET

~/working/exp$./ethtool-exp ens33
ens33 | ethtool_cmd.speed = 1000 
ens33 | ethtool_cmd.duplex = 1 
ens33 | ethtool_cmd.advertising= 239 
ens33 | ethtool_cmd.autoneg = 1 
ens33 | ethtool_cmd.port= 0 
ens33 | ethtool_cmd.phy_address= 0 
ens33 | ethtool_cmd.transceiver= 0 
ens33 | ethtool_cmd.maxrxpkt= 0 
ens33 | ethtool_cmd.maxtxpkt= 0 

使用 ETHTOOL_GLINKSETTINGS

~/working/exp$./ethtool-glink ens33
ens33 | ethtool_link_settings.speed = 0 
ens33 | ethtool_link_settings.duplex = 0 
ens33 | ethtool_link_settings.autoneg = 0