From: Florian Westphal <fw@strlen.de>
To: Daniel Xu <dxu@dxuuu.xyz>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
bpf <bpf@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de,
daniel@iogearbox.net
Subject: Re: [PATCH bpf-next v2 0/8] Support defragmenting IPv(4|6) packets in BPF
Date: Tue, 7 Mar 2023 21:11:56 +0100 [thread overview]
Message-ID: <20230307201156.GF13059@breakpoint.cc> (raw)
In-Reply-To: <20230307194801.mopwvidrkrybm7h5@kashmir.localdomain>
Daniel Xu <dxu@dxuuu.xyz> wrote:
> From my reading (I'll run some tests later) it looks like netfilter
> will defrag all ipv4/ipv6 packets in any netns with conntrack enabled.
> It appears to do so in NF_INET_PRE_ROUTING.
Yes, and output.
> One thing we would need though are (probably kfunc) wrappers around
> nf_defrag_ipv4_enable() and nf_defrag_ipv6_enable() to ensure BPF progs
> are not transitively depending on defrag support from other netfilter
> modules.
>
> The exact mechanism would probably need some thinking, as the above
> functions kinda rely on module_init() and module_exit() semantics. We
> cannot make the prog bump the refcnt every time it runs -- it would
> overflow. And it would be nice to automatically free the refcnt when
> prog is unloaded.
Probably add a flag attribute that is evaluated at BPF_LINK time, so
progs can say they need defrag enabled. Same could be used to request
conntrack enablement.
Will need some glue on netfilter side to handle DEFRAG=m, but we already
have plenty of those.
next prev parent reply other threads:[~2023-03-07 20:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-27 19:51 [PATCH bpf-next v2 0/8] Support defragmenting IPv(4|6) packets in BPF Daniel Xu
2023-02-27 19:51 ` [PATCH bpf-next v2 1/8] ip: frags: Return actual error codes from ip_check_defrag() Daniel Xu
2023-02-27 19:51 ` [PATCH bpf-next v2 3/8] bpf, net, frags: Add bpf_ip_check_defrag() kfunc Daniel Xu
2023-02-28 19:37 ` Stanislav Fomichev
2023-02-28 22:00 ` Daniel Xu
2023-02-28 22:18 ` Stanislav Fomichev
2023-02-27 19:51 ` [PATCH bpf-next v2 4/8] net: ipv6: Factor ipv6_frag_rcv() to take netns and user Daniel Xu
2023-02-27 19:51 ` [PATCH bpf-next v2 5/8] bpf: net: ipv6: Add bpf_ipv6_frag_rcv() kfunc Daniel Xu
2023-02-28 8:15 ` kernel test robot
2023-02-28 9:37 ` kernel test robot
2023-02-27 20:38 ` [PATCH bpf-next v2 0/8] Support defragmenting IPv(4|6) packets in BPF Edward Cree
2023-02-27 22:04 ` Daniel Xu
2023-02-27 22:58 ` Edward Cree
2023-03-01 16:24 ` Daniel Xu
2023-02-27 23:03 ` Alexei Starovoitov
[not found] ` <20230228015712.clq6kyrsd7rrklbz@kashmir.localdomain>
2023-02-28 4:56 ` Alexei Starovoitov
2023-02-28 13:43 ` Daniel Borkmann
2023-02-28 23:17 ` Daniel Xu
2023-03-07 4:17 ` Alexei Starovoitov
2023-03-07 19:48 ` Daniel Xu
2023-03-07 20:11 ` Florian Westphal [this message]
2023-03-07 21:18 ` Alexei Starovoitov
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