How do I set up a proxy server for home with bandwidth control, download limit options?
Solution 1:
Don't do it with Squid : you need control for everything, not just for HTTP on port 80.
The answer requires iptables with the '--quota' option, which implements network quotas by decrementing a byte counter with each packet. The argument of "--quota" is a value in bytes.
There shall be one chain for each user. First rule of the chain counts down a 13 GB quota for packets from 192.168.0.2 and accepts the packet if it is below quota:
iptables -A INPUT -p tcp -s 192.168.0.2 -m quota --quota 13958643712 -j ACCEPT
Second rule of the chain classify over-quota packets in a tc class of your choice :
iptables -A INPUT -p tcp -j CLASSIFY --set-class 1:12
Then it's all classic traffic shaping : http://tldp.org/HOWTO/Traffic-Control-HOWTO/
Of course, you need to use static IP allocation or make sure that DHCP allocates addresses fixed by device's MAC address - and you need to block all addresses but the identified ones of the devices belonging to one of the three users.
By the way, you mention that "when 2 people browse the internet they should get 1 Mbps each, and when 3 people access, they should get 2Mbps divided by 3" but you can do better than that when you set up your traffic classes hierarchy: your requirement should rather be "when two people browse the internet they should not get less that 1 Mbps each, and when three people access, they should get not get less that 2 Mbps divided by 3" so that each can get more if the other people use less than their guaranteed throughput... And tc lets you do that !
Since your router is supported by openwrt and dd-wrt, you have all the tools you need !
Solution 2:
I can't remember off hand if it supports all the features you mention, but I can highly recommend pfSense as a router solution. It's small enough to run of a USB disc, and provides a host of sharing solutions. I had the squid add-on installed for example to provide a transparent proxy to all the internal servers, and even at a package installed to get detailed reporting of network usage.
I also offers internet cafe type features, for example a logon page for guests to use the system. It's easy to set up in a VM, and there is a lot of documentation about how to install it with various different configurations.
I used this at home with 8 other machines. You might find, with it correctly setup, you may not need to introduce the limits as heavily as you have.