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Documentation / cgroups / net_cls.txt


Based on kernel version 4.3. Page generated on 2015-11-02 12:44 EST.

1	Network classifier cgroup
2	-------------------------
3	
4	The Network classifier cgroup provides an interface to
5	tag network packets with a class identifier (classid).
6	
7	The Traffic Controller (tc) can be used to assign
8	different priorities to packets from different cgroups.
9	Also, Netfilter (iptables) can use this tag to perform
10	actions on such packets.
11	
12	Creating a net_cls cgroups instance creates a net_cls.classid file.
13	This net_cls.classid value is initialized to 0.
14	
15	You can write hexadecimal values to net_cls.classid; the format for these
16	values is 0xAAAABBBB; AAAA is the major handle number and BBBB
17	is the minor handle number.
18	Reading net_cls.classid yields a decimal result.
19	
20	Example:
21	mkdir /sys/fs/cgroup/net_cls
22	mount -t cgroup -onet_cls net_cls /sys/fs/cgroup/net_cls
23	mkdir /sys/fs/cgroup/net_cls/0
24	echo 0x100001 >  /sys/fs/cgroup/net_cls/0/net_cls.classid
25		- setting a 10:1 handle.
26	
27	cat /sys/fs/cgroup/net_cls/0/net_cls.classid
28	1048577
29	
30	configuring tc:
31	tc qdisc add dev eth0 root handle 10: htb
32	
33	tc class add dev eth0 parent 10: classid 10:1 htb rate 40mbit
34	 - creating traffic class 10:1
35	
36	tc filter add dev eth0 parent 10: protocol ip prio 10 handle 1: cgroup
37	
38	configuring iptables, basic example:
39	iptables -A OUTPUT -m cgroup ! --cgroup 0x100001 -j DROP
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