xzalloc
void *xzalloc(size_t);
rt->next = xzalloc(sizeof(*rt));
routes = rt = xzalloc(sizeof(*routes));
route->next = xzalloc(sizeof(*route));
routes = route = xzalloc(sizeof(*route));
dhcp = xzalloc(sizeof (*dhcp));
ifp->state->offer = xzalloc(sizeof(*ifp->state->offer));
ifp->state = xzalloc(sizeof(*ifp->state));
ifp->state->options = ifo = xzalloc(sizeof(*ifp->state->options));
iface = xzalloc(sizeof(*iface));
udpp = xzalloc(sizeof(*udpp));