转载于:windeal专栏
Linux 下 可以使用ioctl()函数 以及 结构体 struct ifreq 结构体struct ifconf来获取网络接口的各种信息。
ioctl
首先看ioctl()用法
ioctl()原型如下:
#include <sys/ioctl.h>
int ioctl(int fd, int request, ...);
参数:
fd : 文件描述符
request: 表示要请求的信息。如IP地址、网络掩码等
... : 后面的可变参数根据request而定
比如我们请求所有网络接口的清单:
[cpp] view plaincopyprint?
- struct ifconf IoCtlReq;
- ...
- ioctl( Sock, SIOCGIFCONF, &IoCtlReq )
其中IoCtlReq 是一个
与接口相关的request如下表所示(来源: <http://baike.baidu.com/view/1081282.htm?fr=aladdin>):
接 口 |
SIOCGIFCONF SIOCSIFADDR SIOCGIFADDR SIOCSIFFLAGS SIOCGIFFLAGS SIOCSIFDSTADDR SIOCGIFDSTADDR SIOCGIFBRDADDR SIOCSIFBRDADDR SIOCGIFNETMASK SIOCSIFNETMASK SIOCGIFMETRIC SIOCSIFMETRIC SIOCGIFMTU SIOCxxx |
获取所有接口的清单 设置接口地址 获取接口地址 设置接口标志 获取接口标志 设置点到点地址 获取点到点地址 获取广播地址 设置广播地址 获取子网掩码 设置子网掩码 获取接口的测度 设置接口的测度 获取接口MTU (还有很多取决于系统的实现) |
struct ifconf struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq struct ifreq |
关于ioctl的详细解释清查阅本博其它博文
struct ifreq
结构体 struct ifreq用来保存某个接口的信息。
[cpp] view plaincopyprint?
- // if.h
- /*
- * 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
- union
- {
- char ifrn_name[IFNAMSIZ]; /* if 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 ifru_flags;
- int ifru_ivalue;
- int ifru_mtu;
- struct ifmap ifru_map;
- char ifru_slave[IFNAMSIZ]; /* Just fits the size */
- char ifru_newname[IFNAMSIZ];
- void __user * ifru_data;
- struct if_settings ifru_settings;
- } 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 ifr_settings ifr_ifru.ifru_settings /* Device/proto settings*/
ifr_name 标识了某一接口。
可以通过ioctl获取该接口的信息。如:
ioctl(Sock, SIOCGIFNETMASK, &IfReq);//获取网络接口地址掩码
该代码需要先对IfReq->ifr_name赋值,然后获取与IfReq->ifr_name向匹配的网络接口 的地址掩码
struct ifconf
结构体struct ifconf通常用来保存所有接口信息
[cpp] view plaincopyprint?
- // if.h
- /*
- * 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 {
- char __user *ifcu_buf;
- struct ifreq __user *ifcu_req;
- } ifc_ifcu;
- };
- #define ifc_buf ifc_ifcu.ifcu_buf /* buffer address */
- #define ifc_req ifc_ifcu.ifcu_req /* array of structures */
该结构体可以用来获取所哟网络接口的名字和信息(不是全部信息,是ip地址)