Data Plane Kit using Virtual NIC Device
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Alongside Poll Mode Drivers (PMDs) for both physical and virtual hardware, DPDK also offers pure-software PMDs. One of these is the libpcap-based PMD, which facilitates the reading and writing of packets through libpcap. This capability extends to both files stored on disk and physical NIC devices utilizing standard Linux kernel drivers.
Installation
1. Install the required package.
sudo apt install libpcap-dev
2. Rebuild DPDK to include the support for libpcap.
cd <dpdk installation path> mkdir build meson build # To include the examples meson -Dexamples=all build ninja -C build sudo ninja install -C build
As part of the log from the meson build
command, you should see pcap included as part of the dependencies and in the drivers enabled.
... Run-time dependency libpcap found: YES 1.10.1 ... =============== Drivers Enabled =============== ... net: af_packet, ark, atlantic, avp, axgbe, bnx2x, bnxt, bond, cnxk, cpfl, cxgbe, dpaa, dpaa2, e1000, ena, enetc, enetfec, enic, failsafe, fm10k, gve, hinic, hns3, i40e, iavf, ice, idpf, igc, ionic, ixgbe, memif, netvsc, nfp, ngbe, null, octeontx, octeon_ep, pcap, pfe, qede, ring, sfc, softnic, tap, thunderx, txgbe, vdev_netvsc, vhost, virtio, vmxnet3,
Usage
To use the pcap driver with a unsupported NIC, you have to use the vdev
flag as part of the EAL arguments, following this format:
./<dpdk app> [other EAL options] --vdev 'net_pcap0,iface=<physical network interface>' --vdev 'net_pcap1,iface=<physical network interface>' ... --vdev 'net_pcapN,iface=<physical network interface>' -- [app options]
Where <physical network interface> is the available NIC name, connected to the Linux kernel. To check the name, you can use the script dpdk-devdind.py
included with DPDK.
python3 <dpdk installation path>/usertools/dpdk-devbind.py -s
You should see a similar output, where in this case the physical network interface of interest is enp2s0:
Network devices using kernel driver =================================== 0000:00:14.3 'Cannon Lake PCH CNVi WiFi a370' if=wlo1 drv=iwlwifi unused= *Active* 0000:02:00.0 'RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller 8168' if=enp2s0 drv=r8169 unused= ...
Example
Take for example one of the ethtool sample application, included with DPDK:
sudo build/examples/dpdk-ethtool --vdev 'net_pcap0,iface=enp2s0'
Result
This example is console-driven, in this case, these commands are tested: drvinfo
, link
. In this link is the full list of commands.
EAL: Detected CPU lcores: 12 EAL: Detected NUMA nodes: 1 EAL: Detected static linkage of DPDK EAL: Multi-process socket /var/run/dpdk/rte/mp_socket EAL: Selected IOVA mode 'VA' Number of NICs: 1 Init port 0.. EthApp> drvinfo firmware version get error: (Operation not supported) Port 0 driver: net_pcap (ver: DPDK 23.11.2) firmware-version: bus-info: net_pcap0 EthApp> link Port 0: Up EthApp> quit Closing port 0... Done