Re: [PATCH wpan-next v2 01/11] net: mac802154: Introduce filtering levels

[Alexander Aring <aahringo@redhat.com>]

Hi,

On Fri, Aug 26, 2022 at 10:41 AM Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
>
> The 802154 specification details several filtering levels in which the
> PHY and the MAC could be. The amount of filtering will vary if they are
> in promiscuous mode or in scanning mode. Otherwise they are expected to
> do some very basic checks, such as enforcing the frame validity. Either
> the PHY is able to do so, and the MAC has nothing to do, or the PHY has
> a lower filtering level than expected and the MAC should take over.
>
> For now we define these levels in an enumeration, we add a per-PHY
> parameter showing the PHY filtering level and we set it to a default
> value. The drivers, if they cannot reach this level of filtering, should
> overwrite this value so that it reflects what they do. Then, in the
> core, this filtering level will be used to decide whether some
> additional software processing is needed or not.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  include/net/cfg802154.h |  3 +++
>  include/net/mac802154.h | 24 ++++++++++++++++++++++++
>  net/mac802154/iface.c   |  2 ++
>  3 files changed, 29 insertions(+)
>
> diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
> index 04b996895fc1..2f29e95da47a 100644
> --- a/include/net/cfg802154.h
> +++ b/include/net/cfg802154.h
> @@ -223,6 +223,9 @@ struct wpan_phy {
>         atomic_t hold_txs;
>         wait_queue_head_t sync_txq;
>
> +       /* Current filtering level on reception */
> +       unsigned long filtering;
> +

enum ieee802154_filtering_level?

>         char priv[] __aligned(NETDEV_ALIGN);
>  };
>
> diff --git a/include/net/mac802154.h b/include/net/mac802154.h
> index 357d25ef627a..41c28118790c 100644
> --- a/include/net/mac802154.h
> +++ b/include/net/mac802154.h
> @@ -130,6 +130,30 @@ enum ieee802154_hw_flags {
>  #define IEEE802154_HW_OMIT_CKSUM       (IEEE802154_HW_TX_OMIT_CKSUM | \
>                                          IEEE802154_HW_RX_OMIT_CKSUM)
>
> +/**
> + * enum ieee802154_filtering_level - Filtering levels applicable to a PHY
> + *
> + * @IEEE802154_FILTERING_NONE: No filtering at all, what is received is
> + *     forwarded to the softMAC
> + * @IEEE802154_FILTERING_1_FCS: First filtering level, frames with an invalid
> + *     FCS should be dropped
> + * @IEEE802154_FILTERING_2_PROMISCUOUS: Second filtering level, promiscuous
> + *     mode, identical in terms of filtering to the first level at the PHY
> + *     level, but no ACK should be transmitted automatically and at the MAC
> + *     level the frame should be forwarded to the upper layer directly

You have no ACK back in all filtering levels except in
IEEE802154_FILTERING_4_FRAME_FIELDS. It is some kind of mixed thing
between "receive mode and filtering mode" but I am fine with it.

> + * @IEEE802154_FILTERING_3_SCAN: Third filtering level, enforced during scans,
> + *     which only forwards beacons
> + * @IEEE802154_FILTERING_4_FRAME_FIELDS: Fourth filtering level actually
> + *     enforcing the validity of the content of the frame with various checks
> + */
> +enum ieee802154_filtering_level {
> +       IEEE802154_FILTERING_NONE,
> +       IEEE802154_FILTERING_1_FCS,
> +       IEEE802154_FILTERING_2_PROMISCUOUS,
> +       IEEE802154_FILTERING_3_SCAN,
> +       IEEE802154_FILTERING_4_FRAME_FIELDS,
> +};
> +
>  /* struct ieee802154_ops - callbacks from mac802154 to the driver
>   *
>   * This structure contains various callbacks that the driver may
> diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
> index 500ed1b81250..4bab2807acbe 100644
> --- a/net/mac802154/iface.c
> +++ b/net/mac802154/iface.c
> @@ -587,6 +587,7 @@ ieee802154_setup_sdata(struct ieee802154_sub_if_data *sdata,
>                 sdata->dev->netdev_ops = &mac802154_wpan_ops;
>                 sdata->dev->ml_priv = &mac802154_mlme_wpan;
>                 wpan_dev->promiscuous_mode = false;
> +               wpan_dev->wpan_phy->filtering = IEEE802154_FILTERING_4_FRAME_FIELDS;
>                 wpan_dev->header_ops = &ieee802154_header_ops;
>
>                 mutex_init(&sdata->sec_mtx);
> @@ -601,6 +602,7 @@ ieee802154_setup_sdata(struct ieee802154_sub_if_data *sdata,
>                 sdata->dev->needs_free_netdev = true;
>                 sdata->dev->netdev_ops = &mac802154_monitor_ops;
>                 wpan_dev->promiscuous_mode = true;
> +               wpan_dev->wpan_phy->filtering = IEEE802154_FILTERING_2_PROMISCUOUS;

In my opinion this is currently IEEE802154_FILTERING_NONE ?

- Alex