Re: [net-next,v2,1/5] vrf: add mac header for tunneled packets when sniffer is attached

[Jakub Kicinski]

On Sat,  7 Nov 2020 16:31:35 +0100 Andrea Mayer wrote:
> Before this patch, a sniffer attached to a VRF used as the receiving
> interface of L3 tunneled packets detects them as malformed packets and
> it complains about that (i.e.: tcpdump shows bogus packets).
> 
> The reason is that a tunneled L3 packet does not carry any L2
> information and when the VRF is set as the receiving interface of a
> decapsulated L3 packet, no mac header is currently set or valid.
> Therefore, the purpose of this patch consists of adding a MAC header to
> any packet which is directly received on the VRF interface ONLY IF:
> 
>  i) a sniffer is attached on the VRF and ii) the mac header is not set.
> 
> In this case, the mac address of the VRF is copied in both the
> destination and the source address of the ethernet header. The protocol
> type is set either to IPv4 or IPv6, depending on which L3 packet is
> received.
> 
> Signed-off-by: Andrea Mayer <andrea.mayer@xxxxxxxxxxx>

Please keep David's review tag since you haven't changed the code.