37. TEP termination Sample Application

37.1. Background

With virtualization, overlay networks allow a network structure to be built or imposed across physical nodes which is abstracted away from the actual underlining physical network connections. This allows network isolation, QOS, etc to be provided on a per client basis.

Fig. 37.1 Overlay Networking.

In a typical setup, the network overlay tunnel is terminated at the Virtual/Tunnel End Point (VEP/TEP). The TEP is normally located at the physical host level ideally in the software switch. Due to processing constraints and the inevitable bottleneck that the switch becomes, the ability to offload overlay support features becomes an important requirement. Intel® XL710 10/40 Gigabit Ethernet network card provides hardware filtering and offload capabilities to support overlay networks implementations such as MAC in UDP and MAC in GRE.

37.2. Sample Code Overview

The DPDK TEP termination sample code demonstrates the offload and filtering capabilities of Intel® XL710 10/40 Gigabit Ethernet Controller for VXLAN packet.

The sample code is based on vhost library. The vhost library is developed for user space Ethernet switch to easily integrate with vhost functionality.

The sample will support the followings:

• Tunneling packet recognition.

• The port of UDP tunneling is configurable

• Directing incoming traffic to the correct queue based on the tunnel filter type. The supported filter type are listed below.

  • Inner MAC and VLAN and tenant ID
  • Inner MAC and tenant ID, and Outer MAC
  • Inner MAC and tenant ID

  The tenant ID will be assigned from a static internal table based on the us-vhost device ID. Each device will receive a unique device ID. The inner MAC will be learned by the first packet transmitted from a device.

• Decapsulation of RX VXLAN traffic. This is a software only operation.

• Encapsulation of TX VXLAN traffic. This is a software only operation.

• Inner IP and inner L4 checksum offload.

• TSO offload support for tunneling packet.

The following figure shows the framework of the TEP termination sample application based on vhost-cuse.

Fig. 37.2 TEP termination Framework Overview

37.3. Supported Distributions

The example in this section have been validated with the following distributions:

• Fedora* 18
• Fedora* 19
• Fedora* 20

37.4. Prerequisites

Refer to Prerequisites.

37.5. Compiling the Sample Code

1. Compile vhost lib:

   To enable vhost, turn on vhost library in the configure file config/common_linuxapp.

   CONFIG_RTE_LIBRTE_VHOST=y
   

   vhost user is turned on by default in the configure file config/common_linuxapp. To enable vhost cuse, disable vhost user.

      CONFIG_RTE_LIBRTE_VHOST_USER=n
   
   After vhost is enabled and the implementation is selected, build the vhost library.
   

2. Go to the examples directory:

   export RTE_SDK=/path/to/rte_sdk
   cd ${RTE_SDK}/examples/tep_termination
   

3. Set the target (a default target is used if not specified). For example:

   export RTE_TARGET=x86_64-native-linuxapp-gcc
   

   See the DPDK Getting Started Guide for possible RTE_TARGET values.

4. Build the application:

   cd ${RTE_SDK}
   make config ${RTE_TARGET}
   make install ${RTE_TARGET}
   cd ${RTE_SDK}/examples/tep_termination
   make
   

5. Go to the eventfd_link directory(vhost cuse required):

   cd ${RTE_SDK}/lib/librte_vhost/eventfd_link
   

6. Build the eventfd_link kernel module(vhost cuse required):

   make
   

37.6. Running the Sample Code

1. Install the cuse kernel module(vhost cuse required):

   modprobe cuse
   

2. Go to the eventfd_link directory(vhost cuse required):

   export RTE_SDK=/path/to/rte_sdk
   cd ${RTE_SDK}/lib/librte_vhost/eventfd_link
   

3. Install the eventfd_link module(vhost cuse required):

   insmod ./eventfd_link.ko
   

4. Go to the examples directory:

   export RTE_SDK=/path/to/rte_sdk
   cd ${RTE_SDK}/examples/tep_termination
   

5. Run the tep_termination sample code:

   user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
                   -p 0x1 --dev-basename tep-termination --nb-devices 4
                   --udp-port 4789 --filter-type 1
   

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
                --nb-devices 2

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
                --nb-devices 2 --udp-port 4789

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
            --nb-devices 2 --udp-port 4789 --filter-type 1

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
            --nb-devices 2 --tx-checksum

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
            --tx-checksum --tso-segsz 800

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
            --nb-devices 4 --udp-port 4789 --decap 1

user@target:~$ ./build/app/tep_termination -c f -n 4 --huge-dir /mnt/huge --
            --nb-devices 4 --udp-port 4789 --encap 1

37.7. Running the Virtual Machine (QEMU)

Refer to Running the Virtual Machine (QEMU).

37.8. Running DPDK in the Virtual Machine

Refer to Running DPDK in the Virtual Machine.

37.9. Passing Traffic to the Virtual Machine Device

For a virtio-net device to receive traffic, the traffic’s Layer 2 header must include both the virtio-net device’s MAC address. The DPDK sample code behaves in a similar manner to a learning switch in that it learns the MAC address of the virtio-net devices from the first transmitted packet. On learning the MAC address, the DPDK vhost sample code prints a message with the MAC address and tenant ID virtio-net device. For example:

DATA: (0) MAC_ADDRESS cc:bb:bb:bb:bb:bb and VNI 1000 registered

The above message indicates that device 0 has been registered with MAC address cc:bb:bb:bb:bb:bb and VNI 1000. Any packets received on the NIC with these values are placed on the devices receive queue.