linux-kernel - Re: [PATCH bpf-next 0/7] Support defragmenting IPv(4|6) packets in BPF

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Message-ID: <20230629145315.GB10165@breakpoint.cc>
Date:   Thu, 29 Jun 2023 16:53:15 +0200
From:   Florian Westphal <fw@...len.de>
To:     Toke Høiland-Jørgensen <toke@...hat.com>
Cc:     Florian Westphal <fw@...len.de>, Daniel Xu <dxu@...uu.xyz>,
        bpf@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        coreteam@...filter.org, netfilter-devel@...r.kernel.org,
        daniel@...earbox.net, dsahern@...nel.org
Subject: Re: [PATCH bpf-next 0/7] Support defragmenting IPv(4|6) packets in
 BPF

Toke Høiland-Jørgensen <toke@...hat.com> wrote:
> Florian Westphal <fw@...len.de> writes:
> As for the original question, that's answered by your point above: If
> those two modules are the only ones that are likely to need this, then a
> flag for each is fine by me - that was the key piece I was missing (I'm
> not a netfilter expert, as you well know).

No problem, I was worried I was missing an important piece of kfunc
plumbing :-)

You do raise a good point though.  With kfuncs, module is pinned.
So, should a "please turn on defrag for this bpf_link" pin
the defrag modules too?

For plain netfilter we don't do that, i.e. you can just do
"rmmod nf_defrag_ipv4".  But I suspect that for the new bpf-link
defrag we probably should grab a reference to prevent unwanted
functionality breakage of the bpf prog.