On 08/31/2017 12:01 AM, Cong Wang wrote:
On Wed, Aug 30, 2017 at 2:48 PM, Daniel Borkmann <dan...@iogearbox.net> wrote:
On 08/30/2017 11:30 PM, Cong Wang wrote:
[...]
Note, we still can NOT totally get rid of those class lookup in
->enqueue() because cgroup and flow filters have no way to determine
the classid at setup time, they still have to go through dynamic lookup.
[...]
---
include/net/sch_generic.h | 1 +
net/sched/cls_basic.c | 9 +++++++
net/sched/cls_bpf.c | 9 +++++++
Same is for cls_bpf as well, so bind_class wouldn't work there
either as we could return dynamic classids. bind_class cannot
be added here, too.
I think you are probably right, but the following code is
misleading there:
if (tb[TCA_BPF_CLASSID]) {
prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
tcf_bind_filter(tp, &prog->res, base);
}
If the classid is dynamic, why this tb[TCA_BPF_CLASSID]?
The prog->res.classid is the default one, but can be overridden
later depending on the specified program. cls_bpf_classify() does
after prog return (filter_res holds return code):
[...]
if (filter_res == 0)
continue;
if (filter_res != -1) {
res->class = 0;
res->classid = filter_res;
} else {
*res = prog->res;
}
[...]
Meaning in case of a match (-1), we use the default bound one,
but prog may as well return an alternative found classid if it
wants to. So both versions are possible.
