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From: David Miller <davem@davemloft.net>
To: alexei.starovoitov@gmail.com
Cc: peterpenkov96@gmail.com, netdev@vger.kernel.org, ast@kernel.org,
	daniel@iogearbox.net, simon.horman@netronome.com,
	ppenkov@google.com, willemb@google.com
Subject: Re: [bpf-next RFC 0/3] Introduce eBPF flow dissector
Date: Mon, 20 Aug 2018 19:24:46 -0700 (PDT)	[thread overview]
Message-ID: <20180820.192446.1163576988616844281.davem@davemloft.net> (raw)
In-Reply-To: <20180820205205.jj7e75pulwqkorpr@ast-mbp>

From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Mon, 20 Aug 2018 13:52:07 -0700

> I don't think copy-paste avoids the issue of uapi.
> Anything used by BPF program is uapi.
> The only exception is offsets of kernel internal structures
> passed into bpf_probe_read().
> So we have several options:
> 1. be honest and say 'struct flow_dissect_key*' is now uapi
> 2. wrap all of them into 'struct bpf_flow_dissect_key*' and do rewrites
>   when/if 'struct flow_dissect_key*' changes
> 3. wait for BTF to solve it for tracing use case and for this one two.
 ...
> The idea is that kernel internal structs can be defined in bpf prog
> and since they will be described precisely in BTF that comes with the prog
> the kernel can validate that prog's BTF matches what kernel thinks it has.
> imo that's the most flexible, but BTF for all of vmlinux won't be ready
> tomorrow and looks like this patch set is ready to go, so I would go with 1 or 2.

I would definitely prefer #2 or #3.

I personally would like to see us avoid preventing interesting
optimizations of the flow key layout and/or accesses in the future.

  reply	other threads:[~2018-08-21  5:42 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-16 16:44 [bpf-next RFC 0/3] Introduce eBPF flow dissector Petar Penkov
2018-08-16 16:44 ` [bpf-next RFC 1/3] flow_dissector: implements flow dissector BPF hook Petar Penkov
2018-08-16 18:34   ` Edward Cree
2018-08-16 22:37     ` Willem de Bruijn
2018-08-16 22:40   ` Song Liu
2018-08-16 23:14     ` Petar Penkov
2018-08-20  5:44       ` Song Liu
2018-08-20 14:13         ` Willem de Bruijn
2018-08-20 14:20           ` Daniel Borkmann
2018-08-20 16:04           ` Song Liu
2018-08-16 16:44 ` [bpf-next RFC 2/3] flow_dissector: implements eBPF parser Petar Penkov
2018-08-18 15:50   ` Tom Herbert
2018-08-18 19:49     ` Willem de Bruijn
2018-08-16 16:44 ` [bpf-next RFC 3/3] selftests/bpf: test bpf flow dissection Petar Penkov
2018-08-20 20:52 ` [bpf-next RFC 0/3] Introduce eBPF flow dissector Alexei Starovoitov
2018-08-21  2:24   ` David Miller [this message]
2018-08-22  0:19   ` Petar Penkov
2018-08-22  7:22     ` Daniel Borkmann
2018-08-22  7:28       ` Daniel Borkmann
2018-08-23  0:10         ` Petar Penkov

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