Implement private networks

[tomaka]

Add an equivalent to https://github.com/libp2p/js-libp2p-pnet/

[rklaehn]

I might need this in the near future. Can we get a hint how we would go about implementing this?

[tomaka]

The implementation would be very similar to libp2p-secio: a struct that implements OutboundUpgrade and InboundUpgrade, and that apply the cipher on the stream of data by wrapping around the AsyncRead/AsyncWrite.
The only major difference with secio is the lack of handshake, and that we pass the private shared key directly in the configuration.

[rklaehn]

So I would sneak a manual upgrade into the place where the transport is built, like below, except with a yet to be writtenPrivateSwarmConfig(swarm_key) instead of the PlainText1Config?

    Ok(CommonTransport::new()?
        .and_then(move |io, endpoint| {
            libp2p_core::upgrade::apply(
                io,
                PlainText1Config{},
                endpoint,
                libp2p_core::transport::upgrade::Version::V1,
            )
        })
        .upgrade(core::upgrade::Version::V1)
        .authenticate(secio::SecioConfig::new(keypair))
        .multiplex(core::upgrade::SelectUpgrade::new(yamux::Config::default(), mplex::MplexConfig::new()))
        .map(|(peer, muxer), _| (peer, core::muxing::StreamMuxerBox::new(muxer)))
        .timeout(Duration::from_secs(20)))

[tomaka]

Yes! Normally it should work.

[rklaehn]

Very WIP, but does this go into the right direction?

#1385

[tomaka]

I haven't looked into the details of the logic, but the general structure is what I'd expect, yes.

[tomaka]

Done in #1385