Linking strongSwan statically or dynamically with other modules is making a
combined work based on strongSwan. Thus, the terms and conditions of the GNU
General Public License cover the whole combination.

In addition, as a special exception, the copyright holders of strongSwan give
you permission to combine strongSwan with free software programs or libraries
that are released under the GNU LGPL and with code included in the standard
release of the OpenSSL project's OpenSSL library under the OpenSSL or SSLeay
licenses (or modified versions of such code, with unchanged license). You may
copy and distribute such a system following the terms of the GNU GPL for
strongSwan and the licenses of the other code concerned, provided that you
include the source code of that other code when and as the GNU GPL requires
distribution of source code.

Note that people who make modified versions of strongSwan are not obligated to
grant this special exception for their modified versions; it is their choice
whether to do so. The GNU General Public License gives permission to release a
modified version without this exception; this exception also makes it possible
to release a modified version which carries forward this exception.