netdev - Re: [PATCH v2 net-next 3/4] ionic: restrict received packets to mtu size

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Message-ID: <20200107194536.GB16895@lunn.ch>
Date:   Tue, 7 Jan 2020 20:45:36 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Shannon Nelson <snelson@...sando.io>
Cc:     netdev@...r.kernel.org, davem@...emloft.net
Subject: Re: [PATCH v2 net-next 3/4] ionic: restrict received packets to mtu
 size

> Hi Andrew,
> 

Hi Shannon

> In my experience the driver typically tells the NIC about the current
> max_frame size (e.g. MTU + ETH_HLEN), the NIC only copies max_frame bytes,
> and the NIC returns an error indication on a packets that had more than
> max_frame.

Having played around with a few different NICs for DSA, it seems more
like 75% don't care about the 'MRU' and will happily accept bigger
frames.

Anyway, it does not hurt to drop received frames bigger than what you
can transmit.

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew