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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
       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.clas-
       sid 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 omit-
       ted). 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)