ovpn_addattr
if (ovpn_addattr(msg, max_size, attr, NULL, 0) < 0)
if (ovpn_addattr(&req.n, sizeof(req), IFLA_IFNAME, ovpn->ifname,
if (ovpn_addattr(&req.n, sizeof(req), IFLA_INFO_KIND, OVPN_FAMILY_NAME,
if (ovpn_addattr(&req.n, sizeof(req), IFLA_OVPN_MODE,