copy_essid
printf("%s<%.*s>", tag, copy_essid(ssid, maxlen, ie+2, ie[1]), ssid);
static int copy_essid(char [], size_t, const u_int8_t *, size_t);
curlen = copy_essid(buf, sizeof(buf),
(void)copy_essid(ssid, sizeof(ssid), vp, sr->isr_ssid_len);