On 04/30/2015 02:37 AM, Patrick McHardy wrote:
On 30.04, Pablo Neira Ayuso wrote:
On the bugfix front, the illegal mangling of shared skb from actions
like stateless nat and bpf look also important to be addressed to me.
David already suggested to propagate some state object that keeps a
pointer to the skb that is passed to the action. Thus, the action can
clone it and get the skb back to the ingress path. I started a
patchset to do so here, it's a bit large since it requires quite a lot
of function signature adjustment.
Jumping in on this point - the fact that roughly 2/3 of TC actions will
simply BUG under not unlikely circumstances when used in ingress (I went
through them one by one with Pablo a week ago) is also telling. Nobody
seems to be using that. All packet mangling actions will BUG while any
tap is active. Its nothing easily fixed, but apparently nobody has cared
in ten years. ipt is trivial to crash differently, connmark is as well.
So I'm wondering what are we actually arguing about here. Whether we are
affecting the performance how fast TC will crash? We *do* actually care
about these thing, in TC apparently nobody has for the past ten years.
Totally agree with you that the situation is quite a mess. From tc ingress/
egress side, at least my use case is to have an as minimal as possible entry
point for cls_bpf/act_bpf, which is what we were working on recently. That
is rather ``fresh'' compared to the remaining history of cls/act in tc.
Cheers,
Daniel
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
