Signed-off-by: Keith Wiles <keith.wiles at intel.com> --- doc/guides/nics/tap.rst | 84 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 doc/guides/nics/tap.rst
diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst new file mode 100644 index 0000000..072def8 --- /dev/null +++ b/doc/guides/nics/tap.rst @@ -0,0 +1,84 @@ +.. BSD LICENSE + Copyright(c) 2016 Intel Corporation. All rights reserved. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of Intel Corporation nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +Tun/Tap Poll Mode Driver +======================================== + +The rte_eth_tap.c PMD creates a device using TUN/TAP interfaces on the local +host. The PMD allows for DPDK and the host to communicate using a raw device +interface on the host and in the DPDK application. + +The device created is a TAP device, which sends/receives packet in a raw format +with a L2 header. The usage for a TAP PMD is for connectivity to the local host +using a TAP interface. When the TAP PMD is initialized it will create a number +of tap devices in the host accessed via 'ifconfig -a' or 'ip' command. The +commands can be used to assign and query the virtual like device. + +These TAP interfaces can be used with wireshark or tcpdump or Pktgen-DPDK along +with being able to be used as a network connection to the DPDK application. The +method enable one or more interfaces is to use the --vdev=eth_tap option on the +DPDK application command line. Each --vdev=eth_tap option give will create an +interface named dtap0, dtap1, ... and so forth. + +.. code-block:: console + + The interfaced name can be changed by adding the iface=foo0 + e.g. --vedv=eth_tap,iface=foo0 --vdev=eth_tap,iface=foo1, ... + +.. code-block:: console + + Also the speed of the interface can be changed from 10G to whatever number + needed, but the interface does not enforce that speed. + e.g. --vdev=eth_tap,iface=foo0,speed=25000 + +After the DPDK application is started you can send and receive packets on the +interface using the standard rx_burst/tx_burst APIs in DPDK. From the host point +of view you can use any host tool like tcpdump, wireshark, ping, Pktgen and +others to communicate with the DPDK application. The DPDK application may not +understand network protocols like IPv4/6, UDP or TCP unless the application has +been written to understand these protocols. + +If you need the interface as a real network interface meaning running and has +a valid IP address then you can do this with the following commands: + +.. code-block:: console + + sudo ip link set dtap0 up; sudo ip addr add 192.168.0.250/24 dev dtap0 + sudo ip link set dtap1 up; sudo ip addr add 192.168.1.250/24 dev dtap1 + +Please change the IP addresses as you see fit. + +If routing is enabled on the host you can also communicate with the DPDK App +over the internet via a standard socket layer application as long as you account +for the protocol handing in the application. + +If you have a Network Stack in your DPDK application or something like it you +can utilize that stack to handle the network protocols. Plus you would be able +to address the interface using an IP address assigned to the internal interface. -- 2.8.0.GIT
