ioctl-example

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>


static void usage()
{
	printf("usage : ifconfig interface \n");
	exit(0);
}

int main(int argc, char **argv)
{

	struct sockaddr_in *addr;
	struct ifreq ifr;
	char *name,*address;
	int sockfd;
	if(argc !=2)
		usage();
	else
		name = argv[1];
	sockfd = socket(AF_INET,SOCK_DGRAM,0);
	strncpy(ifr.ifr_name,name,IFNAMSIZ-1);
	if(ioctl(sockfd,SIOCGIFBRDADDR,&ifr)== -1)
		perror("ioctl error"),exit(1);
	addr = (struct sockaddr_in *) &ifr.ifr_broadaddr;
	address = inet_ntoa(addr->sin_addr);
	printf("broad addr:%s",address);

	if(ioctl(sockfd,SIOCGIFNETMASK,&ifr)== -1)
		perror("ioctl error"),exit(1);
	addr = (struct sockaddr_in *) &ifr.ifr_addr;
	address = inet_ntoa(addr->sin_addr);
	printf("inet mask :%s",address);
	
	printf("\n **** \n");
	exit(0);
	
	


}