Re: [PATCH v5 2/2] netfilter: nft_meta: support for time matching

[Jones Desougi <jones.desougi+netfilter@gmail.com>]

The naming of the new meta keys seem a bit confusing.

On Sat, Aug 17, 2019 at 1:19 PM Ander Juaristi <a@juaristi.eus> wrote:
>
> This patch introduces meta matches in the kernel for time (a UNIX timestamp),
> day (a day of week, represented as an integer between 0-6), and
> hour (an hour in the current day, or: number of seconds since midnight).
>
> All values are taken as unsigned 64-bit integers.
>
> The 'time' keyword is internally converted to nanoseconds by nft in
> userspace, and hence the timestamp is taken in nanoseconds as well.
>
> Signed-off-by: Ander Juaristi <a@juaristi.eus>
> ---
>  include/uapi/linux/netfilter/nf_tables.h |  6 ++++
>  net/netfilter/nft_meta.c                 | 46 ++++++++++++++++++++++++
>  2 files changed, 52 insertions(+)
>
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index 82abaa183fc3..b83b62eb4b01 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -799,6 +799,9 @@ enum nft_exthdr_attributes {
>   * @NFT_META_OIFKIND: packet output interface kind name (dev->rtnl_link_ops->kind)
>   * @NFT_META_BRI_IIFPVID: packet input bridge port pvid
>   * @NFT_META_BRI_IIFVPROTO: packet input bridge vlan proto
> + * @NFT_META_TIME_NS: time since epoch (in nanoseconds)
> + * @NFT_META_TIME_DAY: day of week (from 0 = Sunday to 6 = Saturday)

This would be clearer as NFT_META_TIME_WEEKDAY. Just day can mean a
lot of things.
Matches nicely with the added nft_meta_weekday function too.

> + * @NFT_META_TIME_HOUR: hour of day (in seconds)

This isn't really an hour, so why call it that (confuses unit at least)?
Something like NFT_META_TIME_TIMEOFDAY? Alternatively TIMEINDAY.
Presumably the added nft_meta_hour function also derives its name from
this, but otherwise has nothing to do with hours.

>   */
>  enum nft_meta_keys {
>         NFT_META_LEN,
...