swapshort
#define swaplong(a) ((swapshort(a) << 16) | (swapshort(((unsigned)a >> 16))))
if (req.ctl_addr.sin_family == swapshort(AF_INET)) {
swapreq.addr.sin_family = swapshort(req.addr.sin_family);
swapshort(req.ctl_addr.sin_family);