Re: [PATCH 2/2] tools/hotplug: validate mtu read from xenstore against RFC 791 minimum

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Fri, Aug 14, 2026 at 07:03:51AM +0100, James Dingwall wrote:
> From: James Dingwall <james@xxxxxxxxxxxxxx>
> 
> RFC 791 sets the minimum acceptable mtu to 68:
> 
>     Every internet module must be able to forward a datagram of 68
>     octets without further fragmentation.  This is because an internet
>     header may be up to 60 octets, and the minimum fragment is 8 octets.
> 
> In the Linux kernel source:
> 
> include/net/ip.h:#define IPV4_MIN_MTU           68              /* RFC 791 */
> 
> While there is no reason to expect a value <68 to be read from xenstore or
> from the bridge make the value test require a number >= this minimum.
> 
> Signed-off-by: James Dingwall <james@xxxxxxxxxxxxxx>

Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Thanks,


--
Anthony Perard | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech