Internet/LAN data filtering and sharing gateway

I need a win32 console application written in C/C++ that can compile with Visual Studio 6 and run on Windows XP and Windows 7. It is a console application, so NO nice user interface, just a text interface (printf, cin, cout) with configuration taken in a [login to view URL] text file. The application must enable Internet connection sharing via any standard Windows computer. Example: I’m at the hotel with my laptop and I’m getting an Internet connection from the hotel’s WiFi signal, then I want to distribute this Internet connection to other computers via the laptop’s wired Ethernet port and a network switch. In that case, the laptop will be the router implementing NAT and DHCP server. A second application would be to do the same in a local network where the laptop would just acts as a network switch (no NAT) to provide Internet connection to computers in a room where no wired Internet is present (yes, I could do this with a wireless access point device, but I do not want to use another device). The third application is to be able to filter all data to/from the Internet from all computers in a LAN (to prevent access to specific websites, example: block Facebook or other sites access to my employees during normal business hours). Since the application will “relay” all the network data, I also want to be able to log info related to the data and filter the data (pass through or block) based on source/destination MAC/IP/port. I must have all the source code, related documentation, and be able to compile this project with Visual Studio 6. Bonus if this application can run on Linux too.