SCO had a collaboration with IBM called Project Monterey, in which SCO and IBM were merging their operating systems in order to be better positioned for IA64 (which at that point people still thought would be good).
One minor detail of the Monterey deal was that SCO got the right to port IBM's superior networking stack into SCO's operating systems. One part of IBM's networking stack was their implementation of the Berkeley Packet Filter, and that was one of the parts I ported over (I'm pretty sure the file still had a BSD copyright notice on it).
That was back in the days when SCO was a cool UNIX vendor that thought of itself as an extension of UC Santa Cruz. Back then employees couldn't really imagine it turning evil, and it made me wary of what my subsequent employers (Google and Facebook) could turn into.