YaiKe

Yet another implementation of Kademlia in Erlang

Build instructions:

To build, just type make

How to use

There is two ways to use this program

Using dht application

You can use the application dht in order to launch and control one individual node.

In order to launch it, just type application:start(dht). in an erlang shell

Here is the full list of command:

• dht:store(Value) -> To store the value Value on the dht. Returns the Hash which acts as a key
• dht:pull(Hash) -> To retrieve the value associated to the key Hash
• dht:broadcast(Msg) -> To broadcast the message Msg through the dht
• dht:scatter(MsgList) -> To scatter MsgList through the dht
• dht:connect(Node) -> To connect to the node Node. You are responsible to make sure that your node and Node can interact with one other (ie there cookie is the same)
• dht:remove(Hash) -> To remove the value associated to the key Hash
• dht:stats() -> To view some stats about this current node
• dht:stop() -> To stop this current node

Using the client script

The best way to use this dht is to use the client script. This is a small CLI script which allows to control several nodes at once.

To use it, first open an erlang shell with the same cookie as your other shells. Then:

>> c(client).
>> client:start_link().

And your done! You're free to use the following commands in order to interact with the network:

• client:deploy(NodeList) -> NodeList is a list of atom of nodes (ex: ['foo@...', 'bar@...']), then the client will deploy a kademlia node on each of these nodes and link them together
• client:deploy_from_file(Filename) -> Same as the above one, but here Filename is the name of a file containing names of nodes (one per line)
• client:stats() -> output stats about the dht
• client:connect(Node, Other) -> connect node Node to node Other
• client:store(Value) -> Store the value Value on the dht. Returns its key
• client:pull(Hash) -> Returns {found, value} where value is associated to the key Hash if possible, otherwise {notfound}
• client:remove(Hash) -> Remove the value associated to the key Hash
• client:stop(Node) -> Stop the kademlia node from node Node
• client:broadcast(Msg) -> Broadcast Msg on all nodes
• client:scatter(MsgList) -> Scatter MsgList on all nodes
• client:spawn_agent(Node) -> Spawn a kademlia agent remotely on node Node

Example of session:

>> client:deploy("nodes.txt").
>> client:store("bonjour").
>> client:pull(468002421904888468730554770695485051528995388970).
{found, "bonjour"}
>> client:stop('foo@ponce.localdomain').
>> client:pull(468002421904888468730554770695485051528995388970).
{found, "bonjour"}
>> client:remove(468002421904888468730554770695485051528995388970).
>> client:pull(468002421904888468730554770695485051528995388970).
{notfound}

Misc

This is a naive implementation of Kademlia. The routing table is the most naive one and is absolutely not optimized. Thus, several optimizations described in the original papers aren't implemented! Nevertheless, this implementation has a naive key republishing and table refreshing mechanism.