Does Java allow me to passively add data to outgoing network packets?

I'd like to passively include additional data on outgoing packets and retrieve it from incoming packets. Is there a way to do this in Java? Basically I need a method for hooking into 开发者_如何学Cotherwise shimming my own sublayer in the network stack.

The common way to do it in C++ is libpcap or Winpcap libraries. Its Java wrapper has also been implemented, and can be found here.

For packet injection issues, you may use libnet. Unfortunately, it does not have any java wrappers and you should write your own java wrapper by jni.