[PATCH v4 01/13] net: add RX preprocessor support

[Sascha Hauer]

On Fri, Apr 08, 2022 at 10:29:38AM +0200, Oleksij Rempel wrote:
> Add callback for optional rx_preprocessor. This is needed to add DSA
> switch support and demultiplex traffic received from different switch ports.
> 
> Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
> ---
>  include/net.h | 3 +++
>  net/net.c     | 6 ++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/include/net.h b/include/net.h
> index aad28e4f4c..ca9b6cd61e 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -44,9 +44,12 @@ struct eth_device {
>  	void (*halt) (struct eth_device*);
>  	int  (*get_ethaddr) (struct eth_device*, u8 adr[6]);
>  	int  (*set_ethaddr) (struct eth_device*, const unsigned char *adr);
> +	int  (*rx_preprocessor) (struct eth_device*, unsigned char **packet,
> +				 int *length);
>  
>  	struct eth_device *next;
>  	void *priv;
> +	void *rx_preprocessor_priv;
>  
>  	/* phy device may attach itself for hardware timestamping */
>  	struct phy_device *phydev;
> diff --git a/net/net.c b/net/net.c
> index fdb9ab826c..dd2ceb396d 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -708,6 +708,12 @@ int net_receive(struct eth_device *edev, unsigned char *pkt, int len)
>  		goto out;
>  	}
>  
> +	if (edev->rx_preprocessor) {
> +		ret = edev->rx_preprocessor(edev, &pkt, &len);
> +		if (ret == -ENOMSG)
> +			return 0;

ret == -ENOMSG means the packet has been handled by the preprocessor
(and forwarded to the DSA virtual network devices). What about the other
errors that rx_preprocessor can return? Shouldn't we ignore the packet
on other errors?

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |