Implement (finish) circuit switching relay about go-libp2p HOT 3 CLOSED

cc @diasdavid @victorbjelkholm this is relevant to you two because of js-libp2p-relay.

I started working on relay in go-ipfs as part of the "browser accesses go-ipfs" sprint (ipfs/team-mgmt#130).

So far I think the cleanest solution is to make the relay service a transport, so that we get end-to-end encryption -- the existing but unused relay code makes no attempt at that. It might at first feel weird that a swarm protocol is at the same time a transport, but this kind of stack hopping is what you sign up for when building overlay networks. It'll be something like: the RelayService calls Host.NewStream() and Host.SetStreamHandler(), and the Host calls RelayService.AddRelayPeer()

In the end I think this solution is the simplest in that it doesn't have to touch any existing libp2p interfaces. It will also fit in nicely with any future things like transport capabilities and connection estimators.

• /relay multiaddr (/relay-exp for now)
  • Just a PeerID is enough, RelayService picks a suitable peer for relaying
  • Can be explicit though: /ip4/1.2.3.4/tcp/4737/ipfs/Qmfoo/relay/Qmbar
  • Nice side-effect for free: multihop: /relay/Qmfoo/relay/Qmbar/relay/Qmbaz
• RelayService
  • Implements go-libp2p-net.StreamHandler and go-libp2p-transport.Transport
• Config option for relay hosts
  • Probably a static list for now?

from go-libp2p.

The spec is in libp2p/specs, the /p2p-circuit multiaddr has been added to the protocol table, and @dryajov has made great progress on js-libp2p-circuit.

🚢🚢🚢

from go-libp2p.

The spec was revisited and released as 0.1.0 - https://github.com/libp2p/specs/tree/master/relay

from go-libp2p.