1. AF_XDP Support

PF_RING since version 7.5 (note: 7.9 is actually recommended) includes support for AF_XDP adapters, when compiling from source code this is enabled by default (unless the –disable-xdp configure flag is specified).

1.1. Prerequisite

  • PF_RING 7.9.0-6671 or later
  • Dependencies: libelf-dev
  • Kernel: >= 5.4 (configured with CONFIG_XDP_SOCKETS=y)
  • libbpf with latest AF_XDP support installed from <kernel source>/tools/lib/bpf
  • Hugepages loaded

1.2. Kernel Version

Install a kernel >= 5.4, which includes support for unaligned zero-copy buffers. Ubuntu 20 LTS currently runs a kernel 5.4 which fully supports AF_XDP. However the HWE kernel 5.8 is recommended as it provides improved AF_XDP support.

Install libelf-dev:

apt install libelf-dev

On Ubuntu 18.04 you can use uktools available at https://github.com/usbkey9/uktools/ following the instructions below:

git clone https://github.com/usbkey9/uktools && cd uktools

Download and unpack sources for kernel 5.x:

wget http://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.8.tar.xz
tar xvf linux-5.8.tar.xz

Compile and install libbpf:

cd linux-5.8/tools/lib/bpf
sudo make install_lib
sudo make install_headers
sudo ldconfig

1.3. Installation

Install PF_RING as reported in the Installing from packages section on a supported OS with a supported kernel version (e.g. Ubuntu 20) or compile it from source code. In the latter case AF_XDP support should be automatically detected and enabled:

cd PF_RING/userland

Note: the –enable-xdp flag was required on previous pf_ring versions.

Please make sure the below output is printed by the configure script (this means AF_XDP support is actually detected and enabled).

checking PF_RING AF_XDP support... yes

1.4. Load the driver

Load vanilla drivers (use recent drivers that include AF_XDP support, PF_RING ZC drivers should be unloaded as they only support PF_RING ZC mode).

1.5. Load Hugepages

Hugepages are required for the AF_XDP support to work (used for buffers allocation). When installing from packages following the Installing from packages guide it is only required to create /etc/pf_ring/hugepages.conf, otherwise hugepages can be loaded with:

echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
mount -t hugetlbfs nodev /dev/hugepages

1.6. Usage

You are now ready to run any pf_ring sample application using xdp:<interface>@<queue> as interface name. Example:

cd examples
sudo ./pfcount -i xdp:eth1@0

Please note that with AF_XDP pf_ring attaches to a NIC queue, please disable RSS or open all queues.