armプラットフォームネットワーク接続状態のテスト

ifconfig  
eth0      Link encap:Ethernet  HWaddr 00:60:C2:69:06:B5    
          inet addr:10.78.28.114  Bcast:10.78.28.255  Mask:255.255.255.0  
          UP BROADCAST RUNNING MULTICAST MTU:1500  Metric:1   <strong> RUNNING eth1   </strong>
          RX packets:498 errors:0 dropped:0 overruns:0 frame:0  
          TX packets:117 errors:0 dropped:0 overruns:0 carrier:0  
          collisions:0 txqueuelen:1000   
          RX bytes:56899 (55.5 KiB)  TX bytes:11718 (11.4 KiB)  
          Interrupt:111 Base address:0x6000   
   
eth1      Link encap:Ethernet  HWaddr 00:60:C2:69:06:B6    
          inet addr:192.168.2.1  Bcast:192.168.2.255  Mask:255.255.255.0  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1    eth1   
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0  
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0  
          collisions:0 txqueuelen:1000   
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  
          Interrupt:21 Base address:0x4000   
   
lo        Link encap:Local Loopback    
          inet addr:127.0.0.1  Mask:255.0.0.0  
          UP LOOPBACK RUNNING  MTU:16436  Metric:1  
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0  
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0  
          collisions:0 txqueuelen:0   
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  
   

#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <net/if.h>
#include <sys/utsname.h>
#include <limits.h>
#include <ctype.h>
 
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
 
#include <linux/sockios.h>
 
#define ETHTOOL_GLINK       0x0000000a /* Get link status (ethtool_value) */
struct ethtool_value {
            unsigned int   cmd;
                unsigned int   data; 
};  
 
int get_netlink_status(const char *if_name);
 
int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        fprintf(stderr, "usage: %s <ethname>
", argv[0]);
        return -1;
    }
    if (getuid() != 0)
    {
        fprintf(stderr, "Netlink Status Check Need Root user.
");
        return 1;
    }
 
    printf("Net link status: %s
", get_netlink_status(argv[1]) == 1 ? "up" : "down");
    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(const char *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;
}