OLSR HNA support is officially up on ns-3-dev. If you don’t wish to pull the latest ns-3-dev snapshot, feel free to apply the following two patches to your source tree:
1) HNA support, mixed interfaces support and helper improvement for OLSR. (Patch)
2) MID fix for mixed interface integration. (Patch)
Once you’ve applied the patches, you may check out examples/routing/olsr-hna.cc which illustrates how to use the HNA API.