iwtest.c

// build: gcc -o iwtest iwtest.c -liw

#include <stdio.h>
#include <iwlib.h>

int main(int argc, const char **argv) {
	/* Check uid */
	if (getuid() != 0) {
		fprintf(stderr,"must be run as root.\n");
		return 1;
	}
	/* Check for interface name */
	char *ifname;
	if (!(ifname = (char *) argv[1])) {
		fprintf(stderr,"an interface name must be provided.\n");
		return 2;
	}
	/* Get basic wifi info */
	int we_ver, skfd, mode;
	wireless_scan_head context;
	wireless_config cur;
	we_ver = iw_get_kernel_we_version();
	skfd = iw_sockets_open();
	iw_get_basic_config(skfd,ifname,&cur);
	/* Bring up interface (eg "ip link set IFACE up") */
	struct ifreq req;
	int err;
	strncpy(req.ifr_name,ifname,IFNAMSIZ);
	if ( (err=ioctl(skfd,SIOCGIFFLAGS,&req)) ){
		int loop = 0;
		while ( (err=ioctl(skfd,SIOCGIFFLAGS,&req)) ) {
			usleep(100000);
			if (loop++ > 50) break;
		}
		if (err) {
			close(skfd);
			fprintf(stderr,"unable to set \"%s\" down.\n", ifname);
			return 3;
		}
	}
	req.ifr_flags |= IFF_UP;
	if (ioctl(skfd,SIOCSIFFLAGS,&req)) {
		fprintf(stderr,"unable to set \"%s\" up.\n", ifname);
		close(skfd); return 3;
	}
	/* Scan and select network */
	iw_scan(skfd,ifname,we_ver,&context);
	wireless_scan *ws;
	/* list */
	int i = 0;
	for (ws = context.result; ws; ws = ws->next)
		printf("%d: %s\n", ++i, ws->b.essid);
	/* close down */
	iw_sockets_close(skfd);
	return 0;
}