NET_DM_ATTR_TRUNC_LEN
if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
[NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },