Linux 下 可以使用ioctl()函式 以及 結構體 struct ifreq 結構體struct ifconf來獲取網路介面的各種資訊。
轉載於:windeal專欄
Linux 下 可以使用ioctl()函式 以及 結構體 struct ifreq 結構體struct ifconf來獲取網路介面的各種資訊。
ioctl
首先看ioctl()用法
ioctl()原型如下:
#include <sys/ioctl.h>
int ioctl(int fd, int request, ...);
引數:
fd : 檔案描述符
request: 表示要請求的資訊。如IP地址、網路掩碼等
... : 後面的可變引數根據request而定
比如我們請求所有網路介面的清單:
[cpp] view plaincopyprint?
- struct ifconf IoCtlReq;
- ...
- ioctl( Sock, SIOCGIFCONF, &IoCtlReq )
其中IoCtlReq 是一個
與介面相關的request如下表所示(來源: <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 |
獲取所有介面的清單 設定介面地址 獲取介面地址 設定介面標誌 獲取介面標誌 設定點到點地址 獲取點到點地址 獲取廣播地址 設定廣播地址 獲取子網掩碼 設定子網掩碼 獲取介面的測度 設定介面的測度 獲取介面MTU (還有很多取決於系統的實現) |
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
|
關於ioctl的詳細解釋清查閱本博其它博文
struct ifreq
結構體 struct ifreq用來儲存某個介面的資訊。
[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 標識了某一介面。
可以通過ioctl獲取該介面的資訊。如:
ioctl(Sock, SIOCGIFNETMASK, &IfReq);//獲取網路介面地址掩碼
該程式碼需要先對IfReq->ifr_name賦值,然後獲取與IfReq->ifr_name向匹配的網路介面 的地址掩碼
struct ifconf
結構體struct ifconf通常用來儲存所有介面資訊
[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 */
該結構體可以用來獲取所喲網路介面的名字和資訊(不是全部資訊,是ip地址)