View source for DPDK

The [https://www.dpdk.org/ Data Plane Development Kit], a Linux Foundation effort, makes robust userspace Linux networking more or less available to the common hax0r.

==Pollmode driver==

You'll need either a UIO or a VFIO module loaded. VFIO [https://lwn.net/Articles/474088/ is preferable], as it can drive the IOMMU. This is the <tt>vfio-pci</tt> driver. If your system can't work with VFIO, the <tt>uio_pci_generic</tt> or <tt>igb_uio</tt> modules can be employed (the latter is, I believe, specifically for Intel Gigabit NICs). If VFIO is not used, the IOMMU must be disabled, or configured in passthrough mode.

To see physical devices and their bindings, run <tt>dpdk-devbind.py --status</tt>:

<pre>
[schwarzgerat](0) $ dpdk-devbind.py  --status

Network devices using kernel driver
===================================
0000:43:00.0 'I211 Gigabit Network Connection 1539' if=igb drv=igb unused=vfio-pci *Active*
0000:44:00.0 'AQC111 NBase-T/IEEE 802.3bz Ethernet Controller [AQtion] 11b1' if=aq5 drv=atlantic unused=vfio-pci *Active*
0000:45:00.0 'Wi-Fi 6 AX200 2723' if=ax200 drv=iwlwifi unused=vfio-pci *Active*

Crypto devices using kernel driver
==================================
0000:23:00.1 'Starship/Matisse Cryptographic Coprocessor PSPCPP 1486' drv=ccp unused=vfio-pci 
[schwarzgerat](0) $ 
</pre>

After eliminating any routes associated with a device, we can bind it to a DPDK PMD:

<pre>
[schwarzgerat](0) $ sudo dpdk-devbind.py --bind=vfio-pci aq5
[schwarzgerat](0) $ dpdk-devbind.py  --status

Network devices using DPDK-compatible driver
============================================
0000:44:00.0 'AQC111 NBase-T/IEEE 802.3bz Ethernet Controller [AQtion] 11b1' drv=vfio-pci unused=atlantic
</pre>

This has unbound the device from the <tt>atlantic</tt> driver (which can now be unloaded, if we wish). There is no longer any `aq5` interface, but an <tt>nlmon</tt> has shown up.

==Secondary processes==
Tools like <tt>dpdk-pdump</tt> and <tt>dpdk-proc-info</tt> are <i>secondary tools</i>--they require a primary tool to be running, and to have already configured the packet capture framework.