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From: Alexei Starovoitov <ast@plumgrid•com>
To: Daniel Borkmann <daniel@iogearbox•net>,
	"David S. Miller" <davem@davemloft•net>
Cc: Jiri Pirko <jiri@resnulli•us>,
	Jamal Hadi Salim <jhs@mojatatu•com>,
	linux-api@vger•kernel.org, netdev@vger•kernel.org
Subject: Re: [PATCH net-next] tc: cls_bpf: make ingress and egress qdiscs consistent
Date: Fri, 03 Apr 2015 16:11:15 -0700	[thread overview]
Message-ID: <551F1E13.8050508@plumgrid.com> (raw)
In-Reply-To: <551F1C9B.6070908@plumgrid.com>

On 4/3/15 4:04 PM, Alexei Starovoitov wrote:
> On 4/3/15 3:54 PM, Daniel Borkmann wrote:
>> On 04/04/2015 12:17 AM, Alexei Starovoitov wrote:
>> ...
>>> 1. there shouldn't be a choice at all for bpf. Because not pulling l2
>>> means it's bug.
>>
>> Yep, correct. You would also loose context for a possible dissection,
>> at best you only have skb->protocol.
>>
>>> 2. adding a flag means adding it to iproute2 with default off and making
>>> users forgetting it from time to time and have no way of knowing why
>>> their programs all of a sudden stopped working.
>>>
>>> classic falls under the same rules. It doesn't make sense at all to run
>>> a program on packet without L2 header. It's very odd both for classic
>>> and extended programs.
>>
>> Yep.
>>
>>> Two 'if' conditions in critical path is bogus argument, since these
>>> checks would be there in ingress as well. Same critical path.
>>
>> Why bogus? There would be no such test on the normal egress path,
>> where this is irrelevant. I wasn't talking about ingress here.
>>
>> I see the point regarding the user option. So, why not adding a flag
>> to tcf_proto_ops a la `.flags = CLS_REQUIRES_L2` that gets propagated
>> to tcf_proto, and only ingress_enqueue() would need to test if the
>> classifier imposes that requirement, so it can push/pull.
>
> ok. that sounds better, but neither tcf_proto nor tcf_proto_ops have
> 'flags' field today... well, I guess it's time to add flags there.
> Probably add 'flags' to tcf_proto_ops only and do fl->ops->flags in
> ingress_enqueue()?
>
> Will respin.

nope. will take it back.
that doesn't work, since this check cannot be done in ingress_enqueue(),
because it sees the pointer to first filter only, so both TCQ_F_INGRESS
flag and CLS_REQUIRES_L2 flag need to be checked inside
tc_classify_compat() which is a lot worse than my current patch.

So I prefer this patch still :)

  reply	other threads:[~2015-04-03 23:11 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-03 21:16 [PATCH net-next] tc: cls_bpf: make ingress and egress qdiscs consistent Alexei Starovoitov
     [not found] ` <1428095784-7091-1-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-04-03 21:46   ` Daniel Borkmann
     [not found]     ` <551F0A1B.3000100-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2015-04-03 21:52       ` Alexei Starovoitov
     [not found]         ` <551F0B96.2090403-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-04-03 22:10           ` Daniel Borkmann
     [not found]             ` <551F0FE2.8000502-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2015-04-03 22:17               ` Alexei Starovoitov
2015-04-03 22:54                 ` Daniel Borkmann
     [not found]                   ` <551F1A14.7080205-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2015-04-03 23:04                     ` Alexei Starovoitov
2015-04-03 23:11                       ` Alexei Starovoitov [this message]
     [not found]                         ` <551F1E13.8050508-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-04-03 23:26                           ` Daniel Borkmann
2015-04-03 23:48                             ` Daniel Borkmann
2015-04-04  0:14                               ` Alexei Starovoitov
     [not found]                                 ` <551F2CD4.2080502-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-04-04  6:34                                   ` Daniel Borkmann
2015-04-07 18:51   ` David Miller

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