dpdk-kmods can include kernel source code for various operating systems. DPDK is focused on userspace libraries, so it is encouraged contributing and using vanilla kernels as much as possible. Some kernel modules were historically parts of DPDK, and are hosted in its directory kernel/. Now the preference is to contribute kernel modules to the upstream project if possible, otherwise to host kernel code in dpdk-kmods.git. The license can be BSD-3-Clause or GPL-2.0.