1 #define _GNU_SOURCE
2 #include <net/if.h>
3 #include <sys/socket.h>
4 #include <sys/ioctl.h>
5 #include <string.h>
6 #include "syscall.h"
7 
if_nametoindex(const char * name)8 unsigned if_nametoindex(const char *name)
9 {
10 	struct ifreq ifr;
11 	int fd, r;
12 
13 	if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) return 0;
14 	strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
15 	r = ioctl(fd, SIOCGIFINDEX, &ifr);
16 	__syscall(SYS_close, fd);
17 	return r < 0 ? 0 : ifr.ifr_ifindex;
18 }
19