ifgr_groups
if ((ifgr.ifgr_groups = calloc(1, len)) == NULL)
for (ifg = ifgr.ifgr_groups; ifg && len >= sizeof(struct ifg_req);
free(ifgr.ifgr_groups);
ifgp = ifgr->ifgr_groups;
ifgp = ifgr->ifgr_groups;