Cgroup classifier in tc(8)	     Linux	    Cgroup classifier in tc(8)



NAME
       cgroup - control group based traffic control filter

SYNOPSIS
       tc filter ... cgroup [ match EMATCH_TREE ] [  action ACTION_SPEC ]

DESCRIPTION
       This filter serves as a hint to tc that the assigned class ID of the
       net_cls control group the process the packet originates from belongs to
       should be used for classification. Obviously, it is useful for locally
       generated packets only.

OPTIONS
       action ACTION_SPEC
	      Apply an action from the generic actions framework on matching
	      packets.

       match EMATCH_TREE
	      Match packets using the extended match infrastructure. See
	      tc-ematch(8) for a detailed description of the allowed syntax in
	      EMATCH_TREE.

EXAMPLES
       In order to use this filter, a net_cls control group has to be created
       first and class as well as process ID(s) assigned to it. The following
       creates a net_cls cgroup named "foobar":

	      modprobe cls_cgroup
	      mkdir /sys/fs/cgroup/net_cls
	      mount -t cgroup -onet_cls net_cls /sys/fs/cgroup/net_cls
	      mkdir /sys/fs/cgroup/net_cls/foobar

       To assign a class ID to the created cgroup, a file named
       net_cls.classid has to be created which contains the class ID to be
       assigned as a hexadecimal, 64bit wide number. The upper 32bits are
       reserved for the major handle, the remaining hold the minor. So a class
       ID of e.g.  ff:be has to be written like so: 0xff00be (leading zeroes
       may be omitted). To continue the above example, the following assigns
       class ID 1:2 to foobar cgroup:

	      echo 0x10002 > /sys/fs/cgroup/net_cls/foobar/net_cls.classid

       Finally some PIDs can be assigned to the given cgroup:

	      echo 1234 > /sys/fs/cgroup/net_cls/foobar/tasks
	      echo 5678 > /sys/fs/cgroup/net_cls/foobar/tasks

       Now by simply attaching a cgroup filter to a qdisc makes packets from
       PIDs 1234 and 5678 be pushed into class 1:2.


SEE ALSO
       tc(8), tc-ematch(8),
       the file Documentation/cgroups/net_cls.txt of the Linux kernel tree

iproute2			  21 Oct 2015	    Cgroup classifier in tc(8)