Design a decentralized Gnutella like P2P file sharing system

Create a decentralized network in which the peer acts as both client and server. Initialize the network with a config file which has the details of all the peers in the network. Each neighbor looks up the specified file using a local index and responds with a hit query message in the event of a hit where the hit query is propagated in the reverse path of the query. The above has to be done for 2 different network topology.