get_addr.c

一个基于linux的TCP/IP协议栈的实现

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include "my_inet.h"
#include <stdio.h>
#include <errno.h>
#include <string.h>

int main()
{
	struct ifreq req;
	strncpy( req.ifr_name, "eth0", IFNAMSIZ );
	struct sockaddr_in *sin;

	int fd = socket( MY_PF_INET, SOCK_RAW, MY_IPPROTO_ICMP );
	if( fd < 0 ){
		perror("error: ");
		return -1;
	}

	sin = (struct sockaddr_in *)&req.ifr_addr;
	if( ioctl( fd, SIOCGIFADDR, &req) == 0 )
		printf("%s\n", inet_ntoa(sin->sin_addr.s_addr) );
	else
		perror("ioctl error: ");
	
	sin = (struct sockaddr_in *)&req.ifr_broadaddr;
	if( ioctl( fd, SIOCGIFBRDADDR, &req) == 0 )
		printf("%s\n", inet_ntoa(sin->sin_addr.s_addr) );
	else
		perror("ioctl error: ");

	sin = (struct sockaddr_in *)&req.ifr_dstaddr;
	if( ioctl( fd, SIOCGIFDSTADDR, &req) == 0 )
		printf("%s\n", inet_ntoa(sin->sin_addr.s_addr) );
	else
		perror("ioctl error: ");

	sin = (struct sockaddr_in *)&req.ifr_netmask;
	if( ioctl( fd, SIOCGIFNETMASK, &req) == 0 )
		printf("%s\n", inet_ntoa(sin->sin_addr.s_addr) );
	else
		perror("ioctl error: ");

	close( fd );
	return 0;
}