linux打开网卡函数,Linux下利用ioctl函数获取网卡信息

linux打开网卡函数,Linux下利用ioctl函数获取网卡信息

linux下的ioctl函数原型如下：

#include

int ioctl(int handle, int cmd, [int *argc, int argv])

函数成功返回0，失败返回-1.

其相关命令接口如下：

类别

Request

说明

数据类型

套

接

口

SIOCATMARK

SIOCSPGRP

SIOCGPGRP

是否位于带外标记

设置套接口的进程ID 或进程组ID

获取套接口的进程ID 或进程组ID

int

int

int

文

件

FIONBIO

FIOASYNC

FIONREAD

FIOSETOWN

FIOGETOWN

设置/ 清除非阻塞I/O 标志

设置/ 清除信号驱动异步I/O 标志

获取接收缓存区中的字节数

设置文件的进程ID 或进程组ID

获取文件的进程ID 或进程组ID

int

int

int

int

int

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

ARP

SIOCSARP

SIOCGARP

SIOCDARP

创建/ 修改ARP 表项

获取ARP 表项

删除ARP 表项

struct arpreq

struct arpreq

struct arpreq

路

由

SIOCADDRT

SIOCDELRT

增加路径

删除路径

struct rtentry

struct rtentry

在这里我们需要用到的结构体

#include

struct sockaddr_in {

short sin_family; /* Address family */

unsigned short sin_port; /* Port number */

struct in_addr sin_addr; /* Internet address */

unsigned char sin_zero[8]; /* Same size as struct sockaddr */

};

#include

struct ifreq

{

#define IFHWADDRLEN 6

union

{

charifrn_name[IFNAMSIZ];

} ifr_ifrn;

union {

structsockaddr ifru_addr;

structsockaddr ifru_dstaddr;

structsockaddr ifru_broadaddr;

structsockaddr ifru_netmask;

struct sockaddr ifru_hwaddr;

shortifru_flags;

intifru_ivalue;

intifru_mtu;

struct ifmap ifru_map;

charifru_slave[IFNAMSIZ];

charifru_newname[IFNAMSIZ];

void __user * ifru_data;

structif_settings ifru_settings;

} ifr_ifru;

};

#define ifr_name ifr_ifrn.ifrn_name

#define ifr_hwaddr ifr_ifru.ifru_hwaddr

#defineifr_addr ifr_ifru.ifru_addr

#defineifr_dstaddr ifr_ifru.ifru_dstaddr

#defineifr_broadaddr ifr_ifru.ifru_broadaddr

#defineifr_netmask ifr_ifru.ifru_netmask

#defineifr_flags ifr_ifru.ifru_flags

#defineifr_metric ifr_ifru.ifru_ivalue

#defineifr_mtu ifr_ifru.ifru_mtu

#define ifr_map ifr_ifru.ifru_map

#define ifr_slave ifr_ifru.ifru_slave

#defineifr_data ifr_ifru.ifru_data

#define ifr_ifindex ifr_ifru.ifru_ivalue

#define ifr_bandwidth ifr_ifru.ifru_ivalue

#define ifr_qlen ifr_ifru.ifru_ivalue

#define ifr_newname ifr_ifru.ifru_newname

#define ifr_settings ifr_ifru.ifru_setting

ioctl函数能获取到IP地址、子网掩码、广播地址、硬件MAC地址等信息，至于网关及路由表比较复杂，在此不讨论。

具体代码如下：(测试通过)

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

int main()

{

struct sockaddr_in *sin;

struct ifreq ifr;

FILE *dns;

FILE *gw;

char *ip = new char(16);

char *netmask = new char(16);

char *broadcast = new char(16);

//char *ip = (char *)malloc(16);

char *mac = new  char(32);

//char *mac = (char *)malloc(32);

int socket_fd;

if((socket_fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0){

perror("socket");

exit(1);

}

memset(&ifr, 0, sizeof(ifr));

strcpy(ifr.ifr_name, "eth0");

memset(&sin, 0, sizeof(sin));

//获取IP地址

if(ioctl(socket_fd, SIOCGIFADDR, &ifr) != -1){

sin = (struct sockaddr_in *)&ifr.ifr_addr;

strcpy(ip, inet_ntoa(sin->sin_addr));

printf("IP address is %s

", ip);

}

//获取广播地址

if(ioctl(socket_fd, SIOCGIFBRDADDR, &ifr) != -1){

sin = (struct sockaddr_in *)&ifr.ifr_broadaddr;

strcpy(broadcast, inet_ntoa(sin->sin_addr));

printf("Broadcast is %s

", broadcast);

}

//获取子网掩码

if(ioctl(socket_fd, SIOCGIFNETMASK, &ifr) != -1){

sin = (struct sockaddr_in *)&ifr.ifr_broadaddr;

strcpy(netmask, inet_ntoa(sin->sin_addr));

printf("Net-mask is %s

", netmask);

}

//获取硬件MAC地址

if(ioctl(socket_fd, SIOCGIFHWADDR, &ifr) != -1){

sin = (struct sockaddr_in *)&ifr.ifr_netmask;

sprintf(mac, "%02x:%02x:%02x:%02x:%02x:%02x",

(unsigned char)ifr.ifr_netmask.sa_data[0],

(unsigned char)ifr.ifr_netmask.sa_data[1],

(unsigned char)ifr.ifr_netmask.sa_data[2],

(unsigned char)ifr.ifr_netmask.sa_data[3],

(unsigned char)ifr.ifr_netmask.sa_data[4],

(unsigned char)ifr.ifr_netmask.sa_data[5]);

printf("Mac address is %s

", mac);

}

return 0;

}

至于获取网关以及DNS，我是通过相关命令获得的。

主要代码如下：

//获取网关，利用route -n 命令可以看到相关的网关。连接标志是‘UG’

if(gw_fd = popen("route -n | grep 'UG'", "r")){

fread(temp,1,128, gw_fd);

sscanf(temp, "%*s%s", szNetGate);

printf("Gateway is %s

", szNetGate);

}

//获取DNS；一般DNS保存在/f文件中。具体获得方法要根据实际情况而定。

我的配置文件中是这样的

root@nill:/home/arm-none-linux# cat /f

# f(5) file for glibc resolver(3) generated by resolvconf(8)

#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

nameserver 202.96.134.133

上面的202.96.134.133就是我需要获取的主DNS，没有备用DNS

if(dns_fd = popen("cat /f | grep 'nameserver'", "r")){

fread(temp,1,128, gw_fd);

sscanf(temp, "%*s%s%*s%s", szDNS1,szDNS2);

printf("DNS1 is %s",szDNS1);

printf("DNS2is %s", szDNS2);

}