pkt_sched: Control group classifier

The classifier should cover the most common use case and will work
without any special configuration.

The principle of the classifier is to directly access the
task_struct via get_current(). In order for this to work,
classification requests from softirqs must be ignored. This is
not a problem because the vast majority of packets in softirq
context are not assigned to a task anyway. For this to work, a
mechanism is needed to trace softirq context. 

This repost goes back to the method of relying on the number of
nested bh disable calls for the sake of not adding too much
complexity and the option to come up with something more reliable
if actually needed.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 6767e54155db..36543b6fcef3 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -316,6 +316,17 @@ config NET_CLS_FLOW
           To compile this code as a module, choose M here: the
           module will be called cls_flow.
 
+config NET_CLS_CGROUP
+        bool "Control Group Classifier"
+        select NET_CLS
+        depends on CGROUPS
+        ---help---
+          Say Y here if you want to classify packets based on the control
+          cgroup of their process.
+
+          To compile this code as a module, choose M here: the
+          module will be called cls_cgroup.
+
 config NET_EMATCH
         bool "Extended Matches"
         select NET_CLS