Linux下检测网卡与网线连接状态

Linux下检测网卡与网线连接状态：

方法一：使用ioctl向socket发送SIOCETHTOOL命令字

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/sockios.h>
#include <linux/ethtool.h>

int get_netlink_status(constchar *if_name);

int main()
{
    if(getuid()!= 0)
    {
        fprintf(stderr,"Netlink Status Check Need Root Power.\n");
        return 1;
    }

    printf("Net link status: %d\n", get_netlink_status("eth0"));

    return 0;
}

// if_name like "ath0", "eth0". Notice: call this function
// need root privilege.
// return value:
// -1 -- error , details can check errno
// 1 -- interface link up
// 0 -- interface link down.
int get_netlink_status(constchar *if_name)
{
    int skfd;
    struct ifreq ifr;
    struct ethtool_value edata;

    edata.cmd = ETHTOOL_GLINK;
    edata.data = 0;

    memset(&ifr, 0,sizeof(ifr));
    strncpy(ifr.ifr_name, if_name,sizeof(ifr.ifr_name)- 1);
    ifr.ifr_data =(char *) &edata;

    if (( skfd= socket(AF_INET, SOCK_DGRAM, 0 )) < 0)
        return -1;

    if(ioctl( skfd, SIOCETHTOOL,&ifr ) == -1)
    {
        close(skfd);
        return -1;
    }

    close(skfd);
    return edata.data;

}

方法二：使用ifconfigl命令能很方便的查看网卡与网线是否连通：

# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:25:35:68:CC:D6 inet addr:192.168.1.168 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::215:c5ff:fe18:ccd6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:130722 errors:0 dropped:0 overruns:0 frame:0 TX packets:112560 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:104371099 (99.5 MiB) TX bytes:20518584 (19.5 MiB) Interrupt:16

其中的RUNNING就表示网卡与网线正常链接，拔掉网线再运行此命令就会发现RUNNING不在了。 linux系统提供了popen/pclose进程管道让C和shell很方便的交互，下面C代码结合shell命令检测网卡与网线连通状况：

#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <string.h>int GetNetStat( ){    char    buffer[BUFSIZ];    FILE    *read_fp;    int        chars_read;    int        ret;       memset( buffer, 0, BUFSIZ );    read_fp = popen("ifconfig eth0 | grep RUNNING", "r");    if ( read_fp != NULL )    {        chars_read = fread(buffer, sizeof(char), BUFSIZ-1, read_fp);        if (chars_read > 0)        {            ret = 1;        }        else        {            ret = -1;        }        pclose(read_fp);    }    else    {        ret = -1;    }    return ret;}int main(){    int i=0;    i = GetNetStat();    printf( "\nNetStat = %d\n", i );    return 0;}

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Linux下检测网卡与网线连接状态

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