ioctl函数

Ioctl函数

通常用来控制设备,控制特殊设备文件的属性

Int ioctl(int fd, int request, …)

Fd：已经打开的文件描述符

第三个参数一般为char *argp,它随第二个参数request的不同而不同。参数request决定了参数argp是向ioctl传递数据还是从ioctl获取数据。

Ioctl获取网络设备的信息

#include <stdio.h>

#include <unistd.h>

#include <sys/ioctl.h>

#include <stdlib.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <sys/types.h>

#include <net/if.h>

 

unsigned char g_eth_name[16];

unsigned char g_macsddr[6];

unsigned int g_subnetmask;

unsigned int g_ipaddr;

unsigned int g_broadcast_ipaddr;

 

// 初始化网络，获取当前网络设备的信息

void init_net(void)

{

       inti;

       intsock;

       structsockaddr_in sin;

       structifreq ifr;

 

       sock= socket(AF_INET, SOCK_DGRAM, 0);

       if(sock == -1)

       {

              perror("socket");

       }

 

       strcpy(g_eth_name,"eth3");

       strcpy(ifr.ifr_name,g_eth_name);

       printf("ethname:\t%s\n", g_eth_name);

 

       //获取并打印网卡地址

       if(ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)

       {

              perror("ioctl");

       }

       memcpy(g_macsddr,ifr.ifr_hwaddr.sa_data, 6);

 

       printf("localmac:\t");

       for(i = 0; i < 5; i++)

       {

              printf("%.2x:",g_macsddr[i]);

       }

       printf("%.2x\n",g_macsddr[i]);

 

       //获取并打印ip地址

       if(ioctl(sock, SIOCGIFADDR, &ifr) < 0)

       {

              perror("ioctl");

       }

       memcpy(&sin,&ifr.ifr_addr, sizeof(sin));

       g_ipaddr= sin.sin_addr.s_addr;

       printf("localeth0:\t%s\n", inet_ntoa(sin.sin_addr));

 

       //获取并打印广播地址

       if(ioctl(sock, SIOCGIFBRDADDR, &ifr) < 0)

       {

              perror("ioctl");

       }

       memcpy(&sin,&ifr.ifr_addr, sizeof(sin));

       g_broadcast_ipaddr= sin.sin_addr.s_addr;

       printf("broadcast:\t%s\n",inet_ntoa(sin.sin_addr));

 

       //获取并打印子网掩码

       if(ioctl(sock, SIOCGIFNETMASK, &ifr) < 0)

       {

              perror("ioctl");

       }

       memcpy(&sin,&ifr.ifr_addr, sizeof(sin));

       g_subnetmask= sin.sin_addr.s_addr;

       printf("subnetmask:\t%s\n",inet_ntoa(sin.sin_addr));

 

       close(sock);

}

 

int main()

{

       //init

       init_net();

 

       //do something

 

       return0;

}