struct ifconf和struct ifreq，获取网线插入状态
这两天看用C获取当前网口的插入网线状态的程序，遇见了这两个不熟悉的结构体，看了头文件中的说明和详细。
struct ifreq
这个结构定义在include/net/if.h，用来配置ip地址，激活接口，配置MTU等接口信息的
- /* Interface request structure used for socket ioctl's. All interface
- ioctl's must have parameter definitions which begin with ifr_name.
- The remainder may be interface specific. */
- struct ifreq
- {
- # define IFHWADDRLEN 6
- # define IFNAMSIZ IF_NAMESIZE
- union
- {
- char ifrn_name[IFNAMSIZ]; /* Interface name, e.g. "en0". */
- } ifr_ifrn;
- union
- {
- struct sockaddr ifru_addr;
- struct sockaddr ifru_dstaddr;
- struct sockaddr ifru_broadaddr;
- struct sockaddr ifru_netmask;
- struct sockaddr ifru_hwaddr;
- short int ifru_flags;
- int ifru_ivalue;
- int ifru_mtu;
- struct ifmap ifru_map;
- char ifru_slave[IFNAMSIZ]; /* Just fits the size */
- char ifru_newname[IFNAMSIZ];
- __caddr_t ifru_data;
- } ifr_ifru;
- };
- # define ifr_name ifr_ifrn.ifrn_name /* interface name */
- # define ifr_hwaddr ifr_ifru.ifru_hwaddr /* MAC address */
- # define ifr_addr ifr_ifru.ifru_addr /* address */
- # define ifr_dstaddr ifr_ifru.ifru_dstaddr /* other end of p-p lnk */
- # define ifr_broadaddr ifr_ifru.ifru_broadaddr /* broadcast address */
- # define ifr_netmask ifr_ifru.ifru_netmask /* interface net mask */
- # define ifr_flags ifr_ifru.ifru_flags /* flags */
- # define ifr_metric ifr_ifru.ifru_ivalue /* metric */
- # define ifr_mtu ifr_ifru.ifru_mtu /* mtu */
- # define ifr_map ifr_ifru.ifru_map /* device map */
- # define ifr_slave ifr_ifru.ifru_slave /* slave device */
- # define ifr_data ifr_ifru.ifru_data /* for use by interface */
- # define ifr_ifindex ifr_ifru.ifru_ivalue /* interface index */
- # define ifr_bandwidth ifr_ifru.ifru_ivalue /* link bandwidth */
- # define ifr_qlen ifr_ifru.ifru_ivalue /* queue length */
- # define ifr_newname ifr_ifru.ifru_newname /* New name */
- # define _IOT_ifreq _IOT(_IOTS(char),IFNAMSIZ,_IOTS(char),16,0,0)
- # define _IOT_ifreq_short _IOT(_IOTS(char),IFNAMSIZ,_IOTS(short),1,0,0)
- # define _IOT_ifreq_int _IOT(_IOTS(char),IFNAMSIZ,_IOTS(int),1,0,0)
struct ifconf
通常是用来保存所有接口信息的
- /* Structure used in SIOCGIFCONF request. Used to retrieve interface
- configuration for machine (useful for programs which must know all
- networks accessible). */
- struct ifconf
- {
- int ifc_len; /* Size of buffer. */
- union
- {
- __caddr_t ifcu_buf;
- struct ifreq *ifcu_req;
- } ifc_ifcu;
- };
- # define ifc_buf ifc_ifcu.ifcu_buf /* Buffer address. */
- # define ifc_req ifc_ifcu.ifcu_req /* Array of structures. */
- # define _IOT_ifconf _IOT(_IOTS(struct ifconf),1,0,0,0,0) /* not right */
应用
想要获取当前网口网线插入状态，需要用到ifreq结构体，获取网卡的信息，然后socket结合网卡驱动的ioctl，就可以得到与网线插入状态相关的数据。
另外推荐一个百度文库的文章，包含代码
