From: Daniel Borkmann <daniel@iogearbox•net>
To: Hannes Frederic Sowa <hannes@stressinduktion•org>,
stephen@networkplumber•org
Cc: ast@plumgrid•com, jiri@resnulli•us, tgraf@suug•ch,
netdev@vger•kernel.org, Jamal Hadi Salim <jhs@mojatatu•com>
Subject: Re: [PATCH iproute2 -next] tc, bpf: finalize eBPF support for cls and act front-end
Date: Thu, 02 Apr 2015 12:19:32 +0200 [thread overview]
Message-ID: <551D17B4.2090903@iogearbox.net> (raw)
In-Reply-To: <1427934556.1892386.248333013.431CD73B@webmail.messagingengine.com>
On 04/02/2015 02:29 AM, Hannes Frederic Sowa wrote:
> On Thu, Apr 2, 2015, at 02:24, Daniel Borkmann wrote:
>> On 04/02/2015 02:13 AM, Hannes Frederic Sowa wrote:
>> ...
>>> Maybe a small utility programs like:
>>>
>>> bpf (--lookup|--update|--delete|--get-next-key) -fd
>>> filedescriptor-number (type conversion parameters here) key [value]
>>>
>>> So it can be easily used by shell scripts.
>>>
>>> For that the filedescriptor numbers would need to be exported (already
>>> opened) into a spawned shell and the numbers could be specified either
>>> in environment or just by printing text which can be sourced by shells
>>> (we already talked about the maybe exec 5</proc/pid/fd/1234 idea). Seems
>>> this can be just build ontop this current patch by extending the
>>> bpf-agent you already build, no?
>>
>> I was thinking about that and trying it out, but as far as I can tell,
>> due to the anon inodes that are currently underlying as the fd provider,
>> it doesn't work w/o larger kernel changes. So, the file descriptor
>> passing
>> is currently the only way to transfer control.
>
> Does receiving them via af_unix and spawning a new shell with the fds
> already open work?
I'm probably missing something, would that need changes to bash?
I mean exec could bind an fd in the shell to sockets and use that,
for example ...
exec 3<>/dev/tcp/www.slashdot.org/80
echo -e "GET / HTTP/1.1\r\nhost: http://www.slashdot.org\r\nConnection: close\r\n\r\n" >&3
cat <&3
... perhaps such a built-in fake device for retrieving bpf map fds
might be interesting, e.g. exec 4<>/dev/bpf/<obj-file>/<map-name> if
that has been given to bash?
Anyway, I think to have some utility for shell scripts, as you
suggest, certainly sounds interesting!
Thanks,
Daniel
next prev parent reply other threads:[~2015-04-02 10:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-30 22:35 [PATCH iproute2 -next] tc, bpf: finalize eBPF support for cls and act front-end Daniel Borkmann
2015-04-01 5:16 ` Alexei Starovoitov
2015-04-01 8:48 ` Daniel Borkmann
2015-04-01 12:36 ` Jamal Hadi Salim
2015-04-01 14:13 ` Daniel Borkmann
2015-04-01 22:30 ` Thomas Graf
2015-04-08 11:58 ` Jamal Hadi Salim
2015-04-02 0:13 ` Hannes Frederic Sowa
2015-04-02 0:24 ` Daniel Borkmann
2015-04-02 0:29 ` Hannes Frederic Sowa
2015-04-02 10:19 ` Daniel Borkmann [this message]
2015-04-02 11:30 ` Hannes Frederic Sowa
2015-04-02 12:08 ` Daniel Borkmann
2015-04-02 16:14 ` Alexei Starovoitov
2015-04-02 18:38 ` Daniel Borkmann
2015-04-02 12:10 ` Thomas Graf
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