main.c

使用ioctl来读取本地ip和netmask值

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>

int main()
{
    struct ifreq req;
    strncpy( req.ifr_name, "eth0", IFNAMSIZ);
    struct sockaddr_in *sin;
    int fd = socket(AF_INET, SOCK_DGRAM, 0);
    
    if( fd < 0 ){
        perror("error: ");
        return -1;
    }
    sin = (struct sockaddr_in *)&req.ifr_addr;
    if( ioctl( fd, SIOCGIFADDR, &req) == 0 )
        printf("local ip %s\n", inet_ntoa(sin->sin_addr) );
    else
        perror("ioctl error: ");
    sin = (struct sockaddr_in *)&req.ifr_broadaddr;
    if( ioctl( fd, SIOCGIFBRDADDR, &req) == 0 )
        printf("ip broadcast %s\n", inet_ntoa(sin->sin_addr) );
    else
        perror("ioctl error: ");
    sin = (struct sockaddr_in *)&req.ifr_dstaddr;
    if( ioctl( fd, SIOCGIFDSTADDR, &req) == 0 )
        printf("dst ip %s\n", inet_ntoa(sin->sin_addr) );
    else
        perror("ioctl error: ");
    sin = (struct sockaddr_in *)&req.ifr_netmask;
    if( ioctl( fd, SIOCGIFNETMASK, &req) == 0 )
        printf("net mask %s\n", inet_ntoa(sin->sin_addr) );
    else
        perror("ioctl error: ");
    
    close( fd );
    return 0;
}