Todos:
1. Multiple rules with same port get overwritten. Need to fix that
2. Try to look for edge cases and handle them
3. Performance testing against large number of inputs and larger rule set

Testing:
The code was tested by -
1. Checking if the rules have been correctly loaded and the ranges of IP and ports are correctly included. Found Todo #1 during this
2. tweaking the values in fw.accept_packet for edge cases

Design decisions:
The rules are stored in following format:
{
    "direction": {
        "protocol": {
            "port": {
                "octet 1": {
                    "octet 2": {
                        "octet 3": [
                            "octet 4 range"
                        ]
                    }
                }
            }
        }
    }
}

Following tradeoffs were made during the design:
1. Use of a hash/dictionary to store rules so that look up is done in constant amount of time. Also, any updates to the rules would be easily done.
2. The choice of keys within the hash also played an important role. The tradeoff here is reuse some of the keys so that reuse as many keys as possible.
However, keeping fast lookup in mind, the design allowed repetition of IPs per port.
3. This design choice also allows the users to specify fine grained rules at the expense of storage.