/* Test whether a freshly made socket is bound to a device according to SO_BINDTODEVICE. */ #include "udp.h" int main(void) { int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if ( fd < 0 ) err(1, "socket"); #ifdef SO_BINDTODEVICE char ifname[IF_NAMESIZE + 1]; socklen_t ifnamelen = sizeof(ifname); if ( getsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname, &ifnamelen) < 0 ) err(1, "getsockopt: SO_BINDTODEVICE"); ifname[ifnamelen] = '\0'; puts(ifname); #else errno = ENOSYS; err(1, "getsockopt: SO_BINDTODEVICE"); #endif return 0; }