Split lines by polygons in QGIS

I have a river network (lines) and a shp with states (polygon). I would like to split the lines at the state boundaries --> split lines by polygon boundaries.

Is there a geoprocessing tool to do this in QGIS? I can't merge the lines by the way, since they are meaningfully split into tributaries/ main river.

Answer

I have a processing model for that: https://github.com/falu/qgis-split-lines-by-polygons. It works only with qgis 2.4