The WireGuard VPN tunnel is a
fast and easy-to-use solution for those who need or want a secure tunnel
for their traffic. The project has been around since 2016, but it has had a
somewhat circuitous route into Linux; it was merged for the 5.6
kernel, which was released in March 2020. Getting into Linux required
WireGuard developer Jason A. Donenfeld to acquiesce to having WireGuard use some of the
existing kernel crypto primitives, rather than merging his Zinc crypto library. Some of the same
tensions that were seen in that process seem to be cropping up again in the more
recent efforts to add WireGuard support to several BSD kernels.

Source: LWN.net – [$] WireGuard bounces off FreeBSD—for now