torrentkino(1) – Kademlia DHT

SYNOPSIS

tk[46] [-p port] [-r realm] [-d port] [-a port] [-x server] [-y port] [-q] [-l] [-s] hostname

DESCRIPTION

Torrentkino is a Bittorrent DNS resolver. All DNS queries to Torrentkino get
translated into SHA1 hashes and are getting resolved by looking these up in a
Kademlia distributed hash table. It is fully compatible to the DHT as used in
most Bittorrent clients. The swarm becomes the DNS backend for Torrentkino.

By default, Torrentkino sends the first packet to a multicast address. So, for
intranet use cases, you do not need a Bittorrent bootstrap server. Just start
Torrentkino on 2 nodes without any parameters. It simply works.

If you would like to connect nodes around the globe, you may use the Bittorrent
network. Simply select a Bittorrent bootstrap server as seen in the example
below. Your client becomes a full member of the swarm and resolves Bittorrent
SHA1 hashes to IP/port tuples. The swarm on the other end does the same for you.
But in your case, the SHA1 hash represents a hostname instead of a torrent file.

Torrentkino runs as user nobody when started with root priviledges.

OPTIONS

• -p port:
  Listen to this port and use it for the DHT operations. (Default: UDP/6881)

• -P port:
  Listen to this port and use it for the DNS operations. (Default: UDP/5353)

• -a port:
  Announce this port (Default: UDP/8080)

• -n node id string:
  By default a random node id gets computed on every startup. For testing
  purposes it may be useful to keep the same node id all the time. The above
  string is not used directly. Instead its SHA1 hash is used.

• -r realm:
  Creating a realm affects the method to compute the “SHA1” hash. It helps
  you to isolate your nodes and be part of a bigger swarm at the same time.
  This is useful to handle duplicate hostnames. With different realms
  everybody may have his own https://nextcloud.p2p for example.
  Technically, the realm is a SHA1 hash too. It gets merged to the hostname’s
  SHA1 hash by using XOR.

• -x server:
  Use server as a bootstrap server. Otherwise a multicast address is used.
  For LAN only cases the multicast bootstrap is enough.

• -y port:
  The bootstrap server will be addressed at this port. (Default: UDP/6881)

• -l:
  Lazy mode: This option sets multiple predefined bootstrap server like
  router.utorrent.com for example.

• -d:
  Fork and become a daemon.

• -q:
  Be quiet.

NSS

Torrentkino also provides a NSS module. Add tk4 or tk6 to your
/etc/nsswitch.conf file. Hostnames with a .p2p TLD will be redirected to the
Torrentkino daemon. See the examples below.

hosts:          files tk4 dns

EXAMPLES

Announce the hostnames nextcloud.p2p and _http._tcp.foo.bar globally.

$ sudo tk6 -P 53 -l nextcloud.p2p _http._tcp.foo.bar
$ dig AAAA nextcloud.p2p @localhost
$ dig SRV _http._tcp.foo.bar @localhost

Announce the hostname mycloud.p2p within the LAN.

$ sudo tk4 -P 53 mycloud.p2p
$ dig mycloud.p2p @localhost

Isolate your nodes within a realm darkness, fork the process into background
and be quiet.

$ sudo tk6 -r darkness -l -P 53 -d -q torrentkino.cloud
$ dig torrentkino.cloud @localhost

With the NSS daemon in place, you can use the .p2p system-wide.

$ getent hosts nextcloud.p2p
$ ping nextcloud.p2p
$ curl nextcloud.p2p

INSTALLATION

There is a simple installation helper for Debian/Ubuntu. Just run one of the
following commands to create a installable package.

$ make debian
$ make ubuntu

Otherwise, you may use

$ make
$ sudo make install

CREDITS

Thanks to Moritz Warning for his help with the DNS API.