hyperdht

Hyperdht is a golang implementation of a Kademlia based DHT that supports peer discovery and distributed hole punching. It uses a DHT that can make RPC calls to allows nodes to announce that they are listening on a key, and any other nodes can call a lookup on that keys and get that node's public facing address. It can also get the node's local address if both nodes specified local addresses that are in the same subnet in their queries. If the node is behind a NAT the node that ran the lookup can request that the node storing the information act as a STUN server to establish a connection.

Implementation is based on and intended to work with mafintosh's hyperdht written for nodejs. It is built on the following packages also contained in this repository.

kbucket

Package kbucket implements a Kademlia DHT K-Bucket using a binary tree. It is intended to be as minimal as possible and makes as few assumptions as possible about what is being stored. It also makes no assumptions about how an ID is generated or how long it must be. It also allows for contacts whose ID length differs from that of the bucket.

Implementation is based on tristanls's k-bucket written for nodejs.

udpRequest

Package udpRequest allows requests and responses over a net.PacketConn. Each message that is sent is prepended with a short header that indicates whether a packet is a request or a response as well as an ID to match responses to their corresponding request.

In addition to normal requests and responses, udpRequest also allows forwarding requests using the same header that was received and forwarding responses to hosts other than the one the request was received from. However the logic for when this would be appropriate/necessary does not exist in this layer.

Implementation is based on mafintosh's upd-request written for nodejs.

ipencoding

Package ipencoding converts between IP addresses (with ports) and binary buffers. It also handles encoding/decoding "nodes", which are just IDs associated with an IP address. Both IPv4 and IPv6 encodings are supported.

Encoding is originally based on mafintosh's ipv4-peers written for nodejs.

dhtrpc

Package dhtrpc makes calls over a Kademlia based DHT. The DHT uses the udpRequest package to send protobuf encoded messages between peers. Anytime a message containing a valid ID is received the node is stored using the kbucket package, and any responses that are sent will include its stored nodes closest to the target of the request, encoded using the ipencoding package (excluding responses to the special ping query). This allows a DHT node making queries to progressively find and make requests to the nodes closest to the query's target.

Implementation is based on mafintosh's dht-rpc written for nodejs.