Re: [PATCH] net: linearizing skb when downgrade gso_size

[Herbert Xu]

On Tue, Jul 09, 2024 at 11:53:21AM -0400, Willem de Bruijn wrote:
>
> > +		/* Due to header grow, MSS needs to be downgraded.
> > +		 * There is BUG_ON When segment the frag_list with
> > +		 * head_frag true so linearize skb after downgrade
> > +		 * the MSS.
> > +		 */

This sounds completely wrong.  You should never grow the TCP header
by changing gso_size.  What is the usage-scenario for this?

Think about it, if a router forwards a TCP packet, and ends up
growing its TCP header and then splits the packet into two, then
this router is brain-dead.

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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