Re: [PATCH 0/2] net: Set maximum receive packet size on veth interfaces

[Cong Wang]

On Tue, May 9, 2017 at 5:42 PM, Fredrik MarkstrÃm
<fredrik.markstrom@xxxxxxxxx> wrote:
>
> Maybe I was unclear, the veth implementation drops all packers larger then the
> configured MTU (on the receiving interface).
> Most ethernet drivers accepts packets up to the ethernet MTU no matter the
> configured MTU. As far as I can tell from the RFC:s that is ok.

This is because IP layer does the fragmentation for you. But some drivers,
for example tg3, drop packet larger than its dev->mtu very early too.

>
> A simpler solution would be to only drop packets larger then ethernet MTU (like
> most network drivers), but I guess that will break existing stuff
> already out there.

I wonder why did we introduce that mtu check for veth when IP layer
could either fragment or reject with ICMP?