Forban

Forban is a p2p application for link-local and local area networks.

Forban works independently from the Internet and uses only the local area capabilities to announce, discover, search or share files. Forban relies on HTTP and it is "opportunistic".

The name takes its origins from an old French word: http://fr.wiktionary.org/wiki/forban

Forban name can also be a playword in English for banning unwanted software or services on the Internet.

Forban is free software licensed under the GNU Affero General Public License version 3. http://www.fsf.org/licensing/licenses/agpl-3.0.html

A Forban presentation was given at FOSDEM 2011 and another Forban presentation was given at HAXOGREEN 2012.

Installation

The setup is quite easy :

Clone the repository:

git clone [email protected]:adulau/Forban.git

Go to the cloned directory:

cd Forban

and start the Forban processes:

./bin/forbanctl start

Now you can open your favorite browser and go to the following location:

http://127.0.0.1:12555

To share some files, you just need to copy them into ./var/share/

If you want to use another share directory don't forget to copy the ./var/share/forban directory, which contains CSS and images for the website. It can work without these, but it's more handy for users browsing directly to your Forban in passive mode.

Forban protocol

message format used for announce/discovery

announce message

ASCII encoded message use UDP on port 12555 with the following format:

forban;name;<nameoftheforban>;uuid;<identityoftheforban>;hmac;<hmacvaluecofindex>

The messages are flooded in broadcast (IPv4) and use ff02::1 (IPv6) at a regular interval.

Based on the source IP and the destination port used, a HTTP URL is built to get to default forban service.

HTTP services for Forban

The UDP port 12555 is for announcing forban services. The TCP port 12555 is the HTTP server running forban services.

base URL: [REQUIRED] http://:/

index URL where Forban stores its index: [REQUIRED] http://:/s/?g=forban/index

store URL where Forban stores its files and how to get a file: [REQUIRED] http://:/s/?g=base64_urlsafe()&f=b64e

search URL: [OPTIONAL] http://:/q/?v=&r=

REQUIRED interfaces are required to have a full operational Forban protocol in all the modes. The OPTIONAL interfaces are not required for machine-to-machine interaction but used to ease the life of the users.

base64_urlsafe function (b64e)

'+' is replaced by '-'. '/' is replaced by '_'(underscore). '=' is replaced by '!'.

This is following the same approach of MIME::Base64::URLSafe or the python base64.urlsafe_b64encode with an addition of the equal sign being replaced by an exclamation mark.

Forban mode available

• Opportunistic mode
• Shared mode

The opportunistic mode and shared mode use all the REQUIRED components of the protocol. The only difference is the lack of automatic file fetching in the shared mode. The shared mode is usually used in a fixed node content where the opportunistic fetching is not desired (e.g. a fixed bookshelf).

The opportunistic mode works as a simple gossip (or epidemic) protocol to replicate the information from one local to another local Forban.

message format - notes about HMAC

The optional HMAC value has two purposes :

• To know if the index has been updated
• and to verify (if a PSK is set) if the index has been tampered.

When a PSK is not set, the default PSK value is 'Forban'.

The value is optional as other Forban can download any index when they want.

software required

• Python (tested successfully with 2.5, 2.6 and 2.7) - 2.5 is required for the uuid library
• There are no additional Python libraries required