Airtun-ng

Airtun-ng is a virtual tunnel interface creator. There are two basic functions:

Allow all encrypted traffic to be monitored for wireless Intrusion Detection System (wIDS) purposes.
Inject arbitrary traffic into a network.

In order to perform wIDS data gathering, you must have the encryption key and the bssid for the network you wish to monitor. Airtun-ng decrypts all the traffic for the specific network and passes it to a traditional IDS system such as snort.

Traffic injection can be fully bidirectional if you have the full encyption key. It is outgoing unidirectional if you have the PRGA obtained via chopchop or fragmentation attacks. The prime advantage of airtun-ng over the other injection tools in the aircrack-ng suite is that you may use any tool subsequently to create, inject or sniff packets.

Airtun-ng also has repeater and tcpreplay-type functionality. There is a repeater function which allows you to replay all traffic sniffed through a wireless device (interface specified by -i at0) and optionally filter the traffic by a bssid together with a network mask and replay the remaining traffic. While doing this, you can still use the tun interface while repeating. As well, a pcap file read feature allows you to replay stored pcap-format packet captures just the way you captured them in the first place. This is essentially tcpreplay functionality for wifi.

Airtun-ng only runs on linux platforms and does not support WDS.