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)8unsigned 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