cvs commit: src/sys/net if_bridge.c

[Andrew Thompson]

On Wed, Oct 25, 2006 at 05:53:02PM +0000, Darren Reed wrote:
> On Sat, Apr 29, 2006 at 05:37:25AM +0000, Andrew Thompson wrote:
> > thompsa     2006-04-29 05:37:25 UTC
> > 
> >   FreeBSD src repository
> > 
> >   Modified files:
> >     sys/net              if_bridge.c 
> >   Log:
> >   Add support for fragmenting ipv4 packets.
> >   
> >   The packet filter may reassemble the ip fragments and return a packet that is
> >   larger than the MTU of the sending interface. There is no check for DF or icmp
> >   replies as we can only get a large packet to fragment by reassembling a
> >   previous fragment, and this only happens after a call to pfil(9).
> 
> I'm a long time in catching up with this change, but architecturally,
> this change is very very wrong.
> 
> A bridge should have _no_ part in fragmenting up an IP packet
> regardless of what options are set (or not set) in an IP header.

Its not really the bridge that is fragmenting packets. The packet filter
may reassemble fragments and return a packet larger than we can send,
the fragmenting is done in the layer between bridge<->pfil. As long as
we may be returned a large packet this is unavoidable.

I agree that a bridge should not have anything to do with IP, and
technically it isn't.

Andrew