From: Ian Molton <ian.molton@collabora.co.uk>
To: Octavian Purdila <tavi.purdila@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org, rdunlap@xenotime.net,
isdn@linux-pingi.de, paulus@samba.org, arnd@arndb.de,
davem@davemloft.net, herbert@gondor.apana.org.au,
ebiederm@xmission.com, alban.crequy@collabora.co.uk,
astanciu@ixiacom.com
Subject: Re: [PATCH] Add JMEMCMP to Berkeley Packet Filters
Date: Fri, 11 Feb 2011 02:02:11 +0000 [thread overview]
Message-ID: <4D5498A3.5070602@collabora.co.uk> (raw)
In-Reply-To: <AANLkTimOzvMx0FUaqxaa2QVV2FzsuhP8gQVX_CFmhiNR@mail.gmail.com>
On 10/02/11 15:27, Octavian Purdila wrote:
> On Thu, Feb 10, 2011 at 3:35 PM, Ian Molton<ian.molton@collabora.co.uk> wrote:
>> On 10/02/11 13:24, Eric Dumazet wrote:
>>
>> Hi!
>>
>> Thanks for reviewing! :)
>>
>>>> * Can sk_run_filter() be called in a context where kmalloc(GFP_KERNEL) is
>>>> not allowed (I think not)
>>>
>>> You cannot use GFP_KERNEL in sk_run_filter() : We run in {soft}irq mode,
>>> in input path.
>>
>> Ok, that can be sorted.
>>
>>>> * Data section allocated with second call to sock_kmalloc().
>>>> * Should the patch be broken into two - one to add the data uploading,
>>>> one to add the JMEMCMP insn. ?
>>>
>>> May I ask why it is needed at all ?
>>
>> So we can match strings in packet filters... I don't think I understand the
>> question...
>>
>
> Adding a data section (some sort of persistent memory storage that the
> filter can access) is also useful for creating capture triggers, e.g.
> starting capturing after a marker packet has arrived.
Nice to see that people are thinking of more use-cases.
Eric, I think I understand what you meant now...
Our use case is experimental for now, so I wanted to see if other people
would find this useful, as adding an experimental feature that is never
used seems pointless.
In our case, we need to match strings in d-bus packets. if the packet is
not intended for the recipient, it gets dropped, thus avoiding a
pointless context switch.
-Ian
prev parent reply other threads:[~2011-02-11 2:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-10 12:31 [RFD][PATCH] Add JMEMCMP to Berkeley Packet Filters Ian Molton
2011-02-10 12:31 ` [PATCH] " Ian Molton
2011-02-10 13:24 ` Eric Dumazet
2011-02-10 13:35 ` Ian Molton
2011-02-10 15:27 ` Octavian Purdila
2011-02-11 2:02 ` Ian Molton [this message]
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