From: Daniel Borkmann <dborkman@redhat.com>
To: Vladimir Murzin <murzin.v@gmail.com>
Cc: Matt Evans <matt@ozlabs.org>,
paulus@samba.org, netdev <netdev@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org, davem@davemloft.net
Subject: Re: [PATCH] ppc: bpf_jit: support MOD operation
Date: Wed, 04 Sep 2013 09:04:04 +0200 [thread overview]
Message-ID: <5226DB64.3020207@redhat.com> (raw)
In-Reply-To: <52264C0D.3000409@redhat.com>
On 09/03/2013 10:52 PM, Daniel Borkmann wrote:
> On 09/03/2013 09:58 PM, Vladimir Murzin wrote:
[...]
>>> Do you have a test case/suite by any chance ?
>>>
>>> Ben.
>>>
>>
>> Hi Ben!
>>
>> Thanks for your feedback.
>>
>> This patch is only compile tested. I have no real hardware, but I'll
>> probably bring up qemu ppc64 till end of the week...
>> Meanwhile, I've made simple how-to for testing. You can use it if you wish.
>> It is mainly based on the [1] and rechecked on x86-64.
>
> Please also cc netdev on BPF related changes.
>
> Actually, your test plan can be further simplified ...
>
> For retrieving and disassembling the JIT image, we have bpf_jit_disasm [1].
>
> 1) echo 2 > /proc/sys/net/core/bpf_jit_enable
> 2) ... attach filter ...
> 3) bpf_jit_disasm -o
>
> For generating a simple stupid test filter, you can use bpfc [2] (also
> see its man page). E.g. ...
>
> # cat blub
> ldi #10
> mod #8
> ret a
> # bpfc blub
> { 0x0, 0, 0, 0x0000000a },
> { 0x94, 0, 0, 0x00000008 },
> { 0x16, 0, 0, 0x00000000 },
Plus something like ...
ldxi #0
mod x
ret a
For longer-term testing, also trinity has BPF support. ;)
> And load this array e.g. either into a small C program that attaches this
> as BPF filter, or simply do bpfc blub > blub2 and run netsniff-ng -f blub2\
> -s -i eth0, that should also do it.
>
> Then, when attached, the kernel should truncate incoming frames for pf_packet
> into max length of 2, just as an example.
>
> [1] kernel tree, tools/net/bpf_jit_disasm.c
> [2] git clone git://github.com/borkmann/netsniff-ng.git
next prev parent reply other threads:[~2013-09-04 7:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-27 22:49 [PATCH] ppc: bpf_jit: support MOD operation Vladimir Murzin
2013-09-02 17:48 ` Vladimir Murzin
2013-09-02 20:45 ` Benjamin Herrenschmidt
2013-09-03 19:58 ` Vladimir Murzin
2013-09-03 20:52 ` Daniel Borkmann
2013-09-04 7:04 ` Daniel Borkmann [this message]
2013-09-11 16:15 ` Vladimir Murzin
2013-09-12 1:18 ` Matt Evans
2013-09-12 2:56 ` Vladimir Murzin
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