dht

Package dht is a kademlia implementation of a Distributed Hash Table.

It implements bep05 / bep42 / bep43 / bep44

Useful resources

• http://engineering.bittorrent.com/2013/01/22/bittorrent-tech-talks-dht/
• http://www.bittorrent.org/beps/bep_0000.html

TOC

• Api
  • > example/main2.go
• Cli
• Cli Examples
• Credits && inspiration

Api

> example/main2.go

// to test repetitive single lookup.
package main

import (
	"flag"
	"fmt"
	"log"

	"github.com/mh-cbon/dht/bootstrap"
	"github.com/mh-cbon/dht/bucket"
	"github.com/mh-cbon/dht/dht"
	"github.com/mh-cbon/dht/logger"
)

func main2() {
	var v bool
	flag.BoolVar(&v, "vv", false, "verbose mode")
	flag.Parse()

	ready := func(d *dht.DHT) error {
		if v {
			d.AddLogger(logger.Text(log.Printf))
		}
		fmt.Println("Running bootstrap...")
		publicIP, err := d.BootstrapAuto(nil, bootstrap.Public)
		if err != nil {
			return err
		}
		if publicIP != nil {
			log.Printf("public IP bootstrap %v:%v\n", publicIP.IP, publicIP.Port)
		}

		selfID := []byte(d.ID())
		fmt.Printf("your node id %x\n", selfID)

		// that s good, we are ready.

		fmt.Println("Boostrap done...")

		// you can run a lookup to find nodes matching an info_hash or target.
		// info_hash and target are hex string.
		target := "faf5c61ddcc5e8a2dabede0f3b482cd9aea9434c"
		targetID, _ := dht.HexToBytes(target)
		for {
			fmt.Printf("Performing lookup request for %x\n", targetID)
			lookupErr := d.LookupStores(target, nil)
			if lookupErr != nil {
				return lookupErr
			}

			// then get the closest peers for that target
			closest, err := d.ClosestStores(target, 16)
			if err != nil {
				return err
			}
			fmt.Printf("Found %v nodes close to %x\n", len(closest), targetID)
			for _, c := range closest {
				fmt.Printf("%-24v %x %v\n", c.GetAddr(), c.GetID(), bucket.Distance(targetID, c.GetID()))
			}
		}
		return nil
	}
	if err := dht.New(dht.DefaultOps()).Serve(ready); err != nil {
		if err != nil {
			log.Fatal(err)
		}
	}
}

Cli

The provided main.go program helps to play with the bittorrent/dht table.

  -annimplied
    	Announce an implied port.
  -annport int
    	The port of the announce query.
  -blocklist string
    	A peer guardian ip list to block (Some organization:1.0.0.0-1.255.255.255)
  -bnodes string
    	The boostrap node address list seprated by a coma, or public to use pre configured list of public bootstrap nodes, or 'no' to bootstrap empty
  -did string
    	The id of your node in the dht network
  -do string
    	The action to perform boostrap|closest_stores|closest_peers|ping|announce_peer|get_peers|find_node|get|put|genkey|sign (default "boostrap")
  -kconcurrency int
    	The number of nodes to refresh on k-bucket split (default 8)
  -keyname string
    	The name of the key
  -ksize int
    	The size of the k-buckets (default 20)
  -listen string
    	The listen address of the udp socket
  -pip string
    	The public ip of your node to share with other nodes.
  -qconcurrency int
    	The number of simultaneous outgoing requests (default 24)
  -qtimeout string
    	The query timeout (default "1s")
  -remote string
    	The remote address to query ip:port|closest_store|closest_peers
  -salt string
    	The salt to use to put/sign a value.
  -seq int
    	The seq value of get/put.
  -target string
    	Info hash target 20 bytes string hex encoded.
  -tsecret string
    	the secret of the token server
  -val string
    	A value to put.
  -vv
    	verbose mode
  -wait
    	Enter in wait mode after the command ran.

Cli Examples

go run main.go -do closest_peers -target faf5c61ddcc5e8a2dabede0f3b482cd9aea9434c -qtimeout 1s -vv -bnodes public

# run a node on 127...:9091, with an empty bootstrap, verbose, wait mode
go run main.go -listen 127.0.0.1:9091 -wait -bnodes no -vv

# sign a value prints useful information like keys, target etc
go run main.go -do sign -keyname bep44test -val "Hello World!"
go run main.go -do sign -keyname bep44test -val "Hello World!" -salt foobar

# put a value on a specific address (127.0.0.1:9090)
go run main.go -listen 127.0.0.1:9091 -bnodes no -remote "127.0.0.1:9090" -do put -val "Hello World!" -vv
# get a value from a remote
go run main.go -listen 127.0.0.1:9091 -bnodes no -remote "127.0.0.1:9090" -do get -target e5f96f6f38320f0f33959cb4d3d656452117aadb -vv

# put a mutable value on a specific address
go run main.go -listen 127.0.0.1:9091 -bnodes no -remote "127.0.0.1:9090" -do put -keyname bep44test -val "Hello World!" -salt foobar -seq 1 -vv
# get a mutable value on a specific address
go run main.go -listen 127.0.0.1:9091 -bnodes no -remote "127.0.0.1:9090" -do get -keyname bep44test -target 411eba73b6f087ca51a3795d9c8c938d365e32c1 -salt foobar -seq 1 -vv

Credits && inspiration

• https://github.com/anacrolix/dht
• https://github.com/tristanls/k-bucket
• https://github.com/mafintosh/k-rpc
• https://github.com/mafintosh/k-rpc-socket
• https://github.com/feross/bittorrent-dht

Thanks SO!