DTNPerf is the IPerf tool for Delay Tolerant Networks.

DTNPerf measures your DTN goodput, provides custom transmission window, detailed logs, CSV output and many other features.

I developed it for my Bachelor degree in Computer Engineering and now I'm keeping it updated.
DTNPerf is also included into the official DTN distribution, but may happen not to be the latest version... so you can download it from the TATPA website.