Accessing and editing packets of other applications
I am new to programming for Linux. I want to build an application which allows me to capture/see all packets emanating from my system (any process) and make changes to them and perhaps even drop them. Similarly when the system recieves a packet for some application, it should first come to me and then i can make changes to it and then hand it over to the application.
As i said i am new to this. I am using Fedora Core 4. I have got my networking basics done and have also started doing some basic socket programming using C++. I would be grateful if some one can tell me how should i approach my problem.
I have had a look at libpcap and libnet but they dont tell me how i can access packets coming to my system and change them. I can access packets or actually just view them, how can i make actual changes to the packets flowing across?
Thanks in advance and looking forward to any kind of help.
Can the admins please move this to the networking board. Sorry for the trouble.