tinc/COPYING.README

The following applies to tinc:

This program is released under the GPL with the additional exemption that
compiling, linking, and/or using OpenSSL is allowed.  You may provide binary
packages linked to the OpenSSL libraries, provided that all other requirements
of the GPL are met.

The following applies to the LZO library:

  Hereby I grant a special exception to the tinc VPN project
  (http://tinc.nl.linux.org/) to link the LZO library with the OpenSSL library
  (http://www.openssl.org).

  Markus F.X.J. Oberhumer

When tinc is compiled with the --enable-tunemu option, the resulting binary
falls under the GPL version 3 or later.