DATA TRANSFER LIMITATION between O.S. (UBUNTU 12.04 LTS) AND INTERNET.

I have UBUNTU 12.04 LTS OPERATING SYSTEM is installed in my laptop. I need the following: When one of 5 logins are doing work, unlimited internet data transfer should be permitted between UBUNTU 12.04 LTS and internet they are su root login root login mvrp login mbdevi login mjpsri (flexibility to change the above should be provided) and with any other login 25kbit data transfer from O.S. to internet should be permitted. If exceeds, a message should flash that limit exceeded etc. Flexibility to change 25kbit should be provided inside the source code itself. The above should be written in either c or C++ languages only. Source code should be given and compilation procedure and how to execute and where to keep the executable file. Is it necessary to execute after every restart of laptop.