iareq
ifra = &ifctx->iareq;
struct in_aliasreq *ifra = &ifctx->iareq;
ifra = &ifctx->iareq;
struct ifaliasreq iareq;
memset(&iareq, 0, sizeof(iareq));
memcpy(iareq.ifra_name, ifp->if_xname, IFNAMSIZ);
sin = (struct sockaddr_in *)&iareq.ifra_addr;
sin = (struct sockaddr_in *)&iareq.ifra_mask;
sin = (struct sockaddr_in *)&iareq.ifra_broadaddr;
error = ifioctl(so, SIOCAIFADDR, (void *)&iareq, lwp);