ipadm_static_prefixlen
ipaddr->ipadm_static_prefixlen = prefixlen;
newaddr->ipadm_static_prefixlen = 0;
if (ipaddr->ipadm_static_prefixlen == 0) {
&ipaddr->ipadm_static_prefixlen);
(void) plen2mask(ipaddr->ipadm_static_prefixlen, af,
ipaddr->ipadm_static_prefixlen);