Click-MAC Extensions for ns-3-click :: Mid-term Report
The approach has been described in detail on the wiki link: 
Radiotap Support for ns-3's Wifi model Radiotap header support was created at YansWifiPhy::EndReceive() with the necessary modifications to send the headers up the stack through MacLow and MacRxMiddle. A certain amount of Pcap refactoring was done to permit the traces to contain the radiotap information. Further modifications were made for the headers to reach MacHigh, namely RegularWifiMac.
A MonitorMacHigh abstraction The work included the creation of a MonitorMacHigh abstraction that would essentially be a copy of the non-QoS part of RegularWifiMac, an implementation that would work independently of the type of station. Provision of a Monitor Mode was made with the required modifications in WifiNetDevice. The packet reception was then tested at MonitorMacHigh::Receive(), where the radiotap header would be added to the packet.
Test script for Monitor Mode A test script was developed similar to the existing wifi-simple-adhoc-grid example for the purpose of testing the Monitor Mode and the correct working of the MonitorMacHigh class. For this purpose, a lone monitor node was chosen to be in the midst of a grid of AdhocWifiMac nodes capable of communication with each other. The monitor node would be capable of receiving all the packets.
To summarize, this work includes the the Rx side of Monitor Mode and Radiotap support for ns-3's Wifi model.