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tc-cgroup(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



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