linux内核中关于dns数据结构的定义在哪里？解决方法

linux内核中关于dns数据结构的定义在哪里？？
linux内核中关于dns数据结构的定义在哪里？？

谢谢回答！！！

楼主是说这个么？这个是获取不到dns的，只能得到，ip、广播、网关、硬件地址、mtu等
inline int
__nmn_stat_rtr_get_nic_addr(void *addr, const u32 x, const u32 addrtype)
{
struct ifreq ifr;
struct sockaddr_in sin;
int sock = socket(AF_INET, SOCK_DGRAM, 0);
if(-1 == sock){
return ERROR;
}
snprintf(ifr.ifr_name, IFNAMSIZ, "eth%u", x);
ifr.ifr_name[IFNAMSIZ-1] = 0;
if(-1 == ioctl(sock, addrtype, &ifr)){
return ERROR;
}
switch(addrtype)
{
case SIOCGIFADDR:
case SIOCGIFNETMASK:
// case SIOCGIFDSTADDR:
case SIOCGIFBRDADDR:
memcpy(&sin, &(ifr.ifr_dstaddr), sizeof(sin));
memcpy(addr, &sin.sin_addr.s_addr, sizeof(sin.sin_addr.s_addr));
break;
case SIOCGIFHWADDR:
memcpy(addr, &(ifr.ifr_hwaddr.sa_data), 6);
break;
case SIOCGIFMTU:
memcpy(addr, &(ifr.ifr_mtu), sizeof(addr));
break;
default:
return ERROR;
}
return NOERR;
}

C/C++ code

inline int

__nmn_stat_rtr_get_nic_addr(void *addr, const u32 x, const u32 addrtype)

{

    struct ifreq ifr;

    struct sockaddr_in sin;

    int sock = socket(AF_INET, SOCK_DGRAM, 0);

    if(-1 == sock){

        return ERROR;

    }

    snprintf(ifr.ifr_name, IFNAMSIZ, "eth%u", x);

    ifr.ifr_name[IFNAMSIZ-1] = 0;

    if(-1 == ioctl(sock, addrtype, &ifr)){

        return ERROR;

    }

    switch(addrtype)

    {

    case SIOCGIFADDR:

    case SIOCGIFNETMASK:

//    case SIOCGIFDSTADDR:

    case SIOCGIFBRDADDR:

        memcpy(&sin, &(ifr.ifr_dstaddr), sizeof(sin));

        memcpy(addr, &sin.sin_addr.s_addr, sizeof(sin.sin_addr.s_addr));

        break;

    case SIOCGIFHWADDR:

        memcpy(addr, &(ifr.ifr_hwaddr.sa_data), 6);

        break;

    case SIOCGIFMTU:

        memcpy(addr, &(ifr.ifr_mtu), sizeof(addr));

        break;

    default:

        return ERROR;

    }

    return NOERR;

}