cgroup(8) — Linux manual page


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

NAME         top

       cgroup - control group based traffic control filter

SYNOPSIS         top

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

DESCRIPTION         top

       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         top

       action ACTION_SPEC
              Apply an action from the generic actions framework on matching

       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         top

       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         top

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

COLOPHON         top

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iproute2                         21 Oct 2015      Cgroup classifier in tc(8)