Parts of the darkstat source code are covered by a BSD license (actually closer to the ISC license template favored by the OpenBSD project). These are usually the more generalized, reusable parts of the code. Other parts of the darkstat code are covered by the GPL. These other parts are usually not generic code, but are specific to darkstat and its purpose. All of the source code is clearly annotated to show which license covers which parts. Due to the viral nature of the GPL, once linked, the entire darkstat binary is infected with the GPL.