From: Jamal Hadi Salim <jhs@mojatatu•com>
To: Alexei Starovoitov <ast@plumgrid•com>,
David Miller <davem@davemloft•net>
Cc: daniel@iogearbox•net, tgraf@suug•ch, jiri@resnulli•us,
netdev@vger•kernel.org
Subject: Re: [PATCH v3 net-next 2/2] tc: add 'needs_l2' flag to ingress qdisc
Date: Thu, 09 Apr 2015 07:02:52 -0400 [thread overview]
Message-ID: <55265C5C.7020200@mojatatu.com> (raw)
In-Reply-To: <5526593E.4040608@mojatatu.com>
On 04/09/15 06:49, Jamal Hadi Salim wrote:
> On 04/08/15 23:05, Alexei Starovoitov wrote:
> [..]
>> As I said I'd rather disable them attaching to ingress than force
>> all program authors to always use network_offset.
>> Offset 0 points to L2 was always fundamental assumption of BPF.
>
> The issue is not really the ingress qdisc here - rather the ingress
> qdisc tries to cope with _how things work_.
> The challenge is *some netdevs* (not all) strip off the link
> layer _before_ the ingres qdisc sees them. You have to recognize
> those devices and only speacial case with them. Your assumptions of
> blindly pushing/pulling will break in some cases (take a look at
> mirred).
>
To be precise look at:
tcf_mirred_init() and how ok_push based on dev->type is decided.
So we do this in the slow path and make a simple compare in the
fast path on whether push the l2 header.
cheers,
jamal
next prev parent reply other threads:[~2015-04-09 11:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-08 23:26 [PATCH v3 net-next 1/2] net: introduce skb_postpush_rcsum() helper Alexei Starovoitov
2015-04-08 23:26 ` [PATCH v3 net-next 2/2] tc: add 'needs_l2' flag to ingress qdisc Alexei Starovoitov
2015-04-09 2:44 ` David Miller
2015-04-09 3:05 ` Alexei Starovoitov
2015-04-09 3:14 ` David Miller
2015-04-09 3:39 ` Alexei Starovoitov
2015-04-09 5:20 ` Alexei Starovoitov
2015-04-09 5:25 ` David Miller
2015-04-09 15:15 ` Daniel Borkmann
2015-04-09 15:36 ` Eric Dumazet
2015-04-09 17:20 ` Alexei Starovoitov
2015-04-09 10:49 ` Jamal Hadi Salim
2015-04-09 11:02 ` Jamal Hadi Salim [this message]
2015-04-09 15:38 ` Daniel Borkmann
2015-04-10 11:49 ` Jamal Hadi Salim
2015-04-09 17:03 ` Alexei Starovoitov
2015-04-10 12:48 ` Jamal Hadi Salim
2015-04-10 22:35 ` Alexei Starovoitov
2015-04-13 14:28 ` Jamal Hadi Salim
2015-04-13 16:13 ` Alexei Starovoitov
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