lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:   Thu, 11 May 2017 20:27:10 -0700
From:   Cong Wang <>
To:     Fredrik Markström <>
Cc:     David Miller <>,
        Eric Dumazet <>,
        Stephen Hemminger <>,
        Alexei Starovoitov <>,
        Daniel Borkmann <>,
        Linux Kernel Network Developers <>,
        LKML <>,
Subject: Re: [PATCH 0/2] net: Set maximum receive packet size on veth interfaces

On Tue, May 9, 2017 at 5:42 PM, Fredrik Markström
<> 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?

Powered by blists - more mailing lists