LINUX_IFNAMSIZ
lreq.ifr_name[LINUX_IFNAMSIZ-1] = '\0'; /* just in case */
index < LINUX_IFNAMSIZ && lreq.ifr_name[index] != '\0';
MIN(LINUX_IFNAMSIZ, IFNAMSIZ));
char ifrn_name[LINUX_IFNAMSIZ]; /* if name, e.g. "en0" */