[strongSwan] strongswan plugins and GPL

Martin Willi martin at strongswan.org
Thu Oct 2 09:48:39 CEST 2014

Hi Jamie,

> What if I develop my own charon plugin for let's say an IPsec backend?   Is
> this together with charon considered a single program and consequently the
> GPL license follows my plugin?  Obligating me to distribute the source for
> the plugin?

As a plugin heavily relies on the interfaces of strongSwan and gets
linked to the same address space, I'd consider that a "derived work" in
the terms of the GPLv2. This means yes, I'd expect that strongSwan
plugins fall under the GPLv2, and the source must be provided along with
the binaries. But I'm not a lawyer, this is my interpretation.

> So, strongswan is licensed under GPLv2

Yes. If GPL'ing your extension is not possible, you may contact Andreas
for other options.


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