0f22423470
Fixes: 02f96a0a82 ("net/tap: add TUN/TAP device PMD")
Signed-off-by: Keith Wiles <keith.wiles@intel.com>
Acked-by: Pascal Mazon <pascal.mazon@6wind.com>
137 lines
6.3 KiB
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137 lines
6.3 KiB
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.. BSD LICENSE
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Copyright(c) 2016 Intel Corporation. All rights reserved.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of Intel Corporation nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Tun/Tap Poll Mode Driver
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========================
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The ``rte_eth_tap.c`` PMD creates a device using TUN/TAP interfaces on the
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local host. The PMD allows for DPDK and the host to communicate using a raw
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device interface on the host and in the DPDK application.
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The device created is a TAP device, which sends/receives packet in a raw
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format with a L2 header. The usage for a TAP PMD is for connectivity to the
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local host using a TAP interface. When the TAP PMD is initialized it will
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create a number of tap devices in the host accessed via ``ifconfig -a`` or
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``ip`` command. The commands can be used to assign and query the virtual like
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device.
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These TAP interfaces can be used with Wireshark or tcpdump or Pktgen-DPDK
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along with being able to be used as a network connection to the DPDK
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application. The method enable one or more interfaces is to use the
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``--vdev=net_tap0`` option on the DPDK application command line. Each
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``--vdev=net_tap1`` option give will create an interface named dtap0, dtap1,
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and so on.
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The interface name can be changed by adding the ``iface=foo0``, for example::
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--vdev=net_tap0,iface=foo0 --vdev=net_tap1,iface=foo1, ...
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Also the speed of the interface can be changed from 10G to whatever number
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needed, but the interface does not enforce that speed, for example::
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--vdev=net_tap0,iface=foo0,speed=25000
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After the DPDK application is started you can send and receive packets on the
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interface using the standard rx_burst/tx_burst APIs in DPDK. From the host
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point of view you can use any host tool like tcpdump, Wireshark, ping, Pktgen
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and others to communicate with the DPDK application. The DPDK application may
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not understand network protocols like IPv4/6, UDP or TCP unless the
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application has been written to understand these protocols.
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If you need the interface as a real network interface meaning running and has
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a valid IP address then you can do this with the following commands::
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sudo ip link set dtap0 up; sudo ip addr add 192.168.0.250/24 dev dtap0
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sudo ip link set dtap1 up; sudo ip addr add 192.168.1.250/24 dev dtap1
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Please change the IP addresses as you see fit.
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If routing is enabled on the host you can also communicate with the DPDK App
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over the internet via a standard socket layer application as long as you
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account for the protocol handing in the application.
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If you have a Network Stack in your DPDK application or something like it you
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can utilize that stack to handle the network protocols. Plus you would be able
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to address the interface using an IP address assigned to the internal
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interface.
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Example
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-------
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The following is a simple example of using the TUN/TAP PMD with the Pktgen
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packet generator. It requires that the ``socat`` utility is installed on the
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test system.
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Build DPDK, then pull down Pktgen and build pktgen using the DPDK SDK/Target
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used to build the dpdk you pulled down.
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Run pktgen from the pktgen directory in a terminal with a commandline like the
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following::
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sudo ./app/app/x86_64-native-linuxapp-gcc/app/pktgen -l 1-5 -n 4 \
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--proc-type auto --log-level 8 --socket-mem 512,512 --file-prefix pg \
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--vdev=net_tap0 --vdev=net_tap1 -b 05:00.0 -b 05:00.1 \
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-b 04:00.0 -b 04:00.1 -b 04:00.2 -b 04:00.3 \
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-b 81:00.0 -b 81:00.1 -b 81:00.2 -b 81:00.3 \
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-b 82:00.0 -b 83:00.0 -- -T -P -m [2:3].0 -m [4:5].1 \
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-f themes/black-yellow.theme
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.. Note:
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Change the ``-b`` options to blacklist all of your physical ports. The
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following command line is all one line.
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Also, ``-f themes/black-yellow.theme`` is optional if the default colors
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work on your system configuration. See the Pktgen docs for more
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information.
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Verify with ``ifconfig -a`` command in a different xterm window, should have a
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``dtap0`` and ``dtap1`` interfaces created.
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Next set the links for the two interfaces to up via the commands below::
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sudo ip link set dtap0 up; sudo ip addr add 192.168.0.250/24 dev dtap0
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sudo ip link set dtap1 up; sudo ip addr add 192.168.1.250/24 dev dtap1
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Then use socat to create a loopback for the two interfaces::
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sudo socat interface:dtap0 interface:dtap1
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Then on the Pktgen command line interface you can start sending packets using
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the commands ``start 0`` and ``start 1`` or you can start both at the same
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time with ``start all``. The command ``str`` is an alias for ``start all`` and
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``stp`` is an alias for ``stop all``.
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While running you should see the 64 byte counters increasing to verify the
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traffic is being looped back. You can use ``set all size XXX`` to change the
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size of the packets after you stop the traffic. Use pktgen ``help``
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command to see a list of all commands. You can also use the ``-f`` option to
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load commands at startup in command line or Lua script in pktgen.
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