From owner-freebsd-net@FreeBSD.ORG  Fri Mar 13 14:22:54 2009
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Date: Fri, 13 Mar 2009 09:22:46 -0500 (CDT)
From: "Sean C. Farley" <scf@FreeBSD.org>
To: Rui Paulo <rpaulo@FreeBSD.org>
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Cc: freebsd-net@FreeBSD.org
Subject: Re: tap(4) SIOCSIFMTU patch
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On Fri, 13 Mar 2009, Rui Paulo wrote:

> On 13 Mar 2009, at 01:54, Sean C. Farley wrote:
>
>> Here is a patch[1] that will allow the MTU to be set higher than 1500 
>> on a tap(4) interface.  I ran into the need to do this when I had em0 
>> set to 9000 and tried to bridge em0 with tap0 (MTU 1500) for QEMU.  A 
>> bridge interface will not allow interfaces with different MTU's to be 
>> added to it.
>> 
>> Since I have touched little inside the kernel, I thought it best if 
>> others take a look at it first.
>> 
>> Sean
>> 1. http://people.freebsd.org/~scf/if_tap-SIOCSIFMTU.patch
>
> This looks ok. I'm assuming bridge now works for you.

Thank you for reviewing it.

Yes, this fixes my issue with bridging a tap device to an interface with 
an MTU higher than 1500.

I will probably commit this patch this weekend.

Sean
-- 
scf@FreeBSD.org