978eb3676f
We have a peerstore that keeps all data for all observed peers in memory with no eviction. This is fine when you don't discover many peers but when using the DHT you encounter a significant number of peers so our peer storage grows and grows over time. We have a persistent peer store, but it just periodically writes peers into the datastore to be read at startup, still keeping them in memory. It also means a restart doesn't give you any temporary reprieve from the memory leak as the previously observed peer data is read into memory at startup. This change refactors the peerstore to use a datastore by default, reading and writing peer info as it arrives. It can be configured with a MemoryDatastore if desired. It was necessary to change the peerstore and *book interfaces to be asynchronous since the datastore api is asynchronous. BREAKING CHANGE: `libp2p.handle`, `libp2p.registrar.register` and the peerstore methods have become async
Connection Encryption
libp2p can leverage the encrypted communications from the transports it uses (i.e WebRTC). To ensure that every connection is encrypted, independently of how it was set up, libp2p also supports a set of modules that encrypt every communication established.
We call this usage a connection upgrade where given a connection between peer A to peer B, a protocol handshake can be performed that gives that connection new properties.
A byproduct of having these encrypted communications modules is that we can authenticate the peers we are dialing to. You might have noticed that every time we dial to a peer in libp2p space, we always use its PeerId at the end (e.g /ip4/127.0.0.1/tcp/89765/p2p/QmWCbVw1XZ8hiYBwwshPce2yaTDYTqTaP7GCHGpry3ykWb), this PeerId is generated by hashing the Public Key of the peer. With this, we can create a crypto challenge when dialing to another peer and prove that peer is the owner of a PrivateKey that matches the Public Key we know.
1. Set up encrypted communications
We will build this example on top of example for Protocol and Stream Multiplexing. You will need the @chainsafe/libp2p-noise module to complete it, go ahead and npm install @chainsafe/libp2p-noise.
To add them to your libp2p configuration, all you have to do is:
const Libp2p = require('libp2p')
const { NOISE } = require('@chainsafe/libp2p-noise')
const createNode = () => {
return Libp2p.create({
modules: {
transport: [ TCP ],
streamMuxer: [ Mplex ],
// Attach noise as the crypto channel to use
connEncryption: [ NOISE ]
}
})
}
And that's it, from now on, all your libp2p communications are encrypted. Try running the example 1.js to see it working.