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