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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  gen‐
       erated 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  han‐
       dle,  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)