Actually, they have already suspended the service for sci-hub, albeit under a court order.
https://yro.slashdot.org/story/18/02/05/1944225/cloudflare-t...
707 karma · joined October 18, 2016
https://yro.slashdot.org/story/18/02/05/1944225/cloudflare-t...
Packages like STunnel/stunnel might help(available for both windows/linux).