Question

I want to write a program which Controls all the web browsing activities on PC.
i.e. Checking all the websites users go to, filtering some of them, … .

But I have no idea how to capture all the packets, processing them, and even act to some (think of filtering unwanted sites).

Any help, sample code, open source program…?

Answer 1

There are different levels you can put yourself in the middle of the communication:

1. By implementing a proxy and having the browser connect to the proxy
2. By implementing a firewall/snooper and handling the raw packets
3. By implementing a network driver and handling the raw packets

IMHO, number 1 is easiest. Look at SQUID for an example. Number 2 is doable too, take a look at fiddler. You could take a look at the Click Modular Router for option number 3.

Depending on the browser, maybe a simple browser plugin could do?