Linux下如何用C语言获得网络信息，比如IP，掩码，mac地址，网关

在Linux下执行以下程序：

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

int main( )
{

    FILE* netinfo = popen("/sbin/ifconfig", "r");
       
    if(!netinfo){
        puts("error while open pipe");
        exit(1);
    }  

    char str[200];
       
    while( fgets(str, 199, netinfo) != NULL ){ 
        printf("%s", str);
    }  
       
    pclose(netinfo);

}

[root@localhost ~]# ./test 
eth0      Link encap:Ethernet  HWaddr 00:0C:29:44:FB:6D  
          inet addr:192.168.232.128  Bcast:192.168.232.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe44:fb6d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:24 errors:0 dropped:0 overruns:0 frame:0
          TX packets:44 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:7666 (7.4 KiB)  TX bytes:6087 (5.9 KiB)
          Interrupt:18 Base address:0x2024 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:1706 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1706 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:2640180 (2.5 MiB)  TX bytes:2640180 (2.5 MiB)