struct ifreq是什么结构,该怎么解决

struct ifreq是什么结构
struct   ifreq是什么结构
有详细信息的请给我帖以下

------解决方案--------------------
struct ifreq {
char ifr_name[IFNAMSIZ]; /* interface name, e.g., "le0 " */
union {
struct sockaddr ifru_addr;
struct sockaddr ifru_dstaddr;
struct sockaddr ifru_broadaddr;
short ifru_flags;
int ifru_metric;
caddr_t ifru_data;
} ifr_ifru;
};