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Date:   Fri, 31 Jul 2020 00:28:08 +0200
From:   Florian Westphal <fw@strlen.de>
To:     Michael Zhou <mzhou@cse.unsw.edu.au>
Cc:     Pablo Neira Ayuso <pablo@netfilter.org>,
        netfilter-devel@vger.kernel.org
Subject: Re: TEST Re: [PATCH] net/ipv6/netfilter/ip6t_NPT: rewrite addresses
 in ICMPv6 original packet
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References: <20200720131701.17941-1-mzhou@cse.unsw.edu.au>
 <20200729204323.GA11285@salvia>
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Michael Zhou <mzhou@cse.unsw.edu.au> wrote:
> Thanks for the comments.
> 
> On Wed, 29 Jul 2020 22:43:23 +0200
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> 
> > This ICMPv6 header might fall withing the non-linear data of the
> > skbuff.
> 
> Might you be able to point me to an example of how to handle and test
> this? So far in my testing it has always been in the linear data.

Look at skb_header_pointer() function and other users of it.

> > BTW, does rfc6296 describes what to do with icmp traffic?
> 
> Unfortunately not. Do you think this functionality should be an
> optional flag or be part of a different target to maintain conformance
> with the RFC?

Handling it automatically seems sane to me.