udx-native

udx is reliable, multiplexed, and congestion-controlled streams over udp.

npm i udx-native

It's a transport protocol, made only for peer-to-peer networking.

No handshakes. No encryption. No features. This is good for P2P.
Just fast streams and messages that are composable into powerful things.

Usage

const UDX = require('udx-native')

const u = new UDX()
const a = u.createSocket()
const b = u.createSocket()

b.on('message', function (message) {
  console.log('received', message.toString())
  a.close()
  b.close()
})

b.bind(0)
a.send(Buffer.from('hello'), b.address().port)

const UDX = require('udx-native')

const u = new UDX()

const socket1 = u.createSocket()
const socket2 = u.createSocket()

socket1.bind()
socket2.bind()

const stream1 = u.createStream(1)
const stream2 = u.createStream(2)

stream1.connect(socket1, stream2.id, socket2.address().port, '127.0.0.1')
stream2.connect(socket2, stream1.id, socket1.address().port, '127.0.0.1')

stream1.write(Buffer.from('hello'))
stream1.end()

stream2.on('data', function (data) {
  console.log(data)
})

stream2.on('end', function () {
  stream2.end()
})

stream1.on('close', function () {
  console.log('stream1 closed')
  socket1.close()
})

stream2.on('close', function () {
  console.log('stream2 closed')
  socket2.close()
})

API

const udx = new UDX()

Creates a new UDX instance.

const bool = UDX.isIPv4(host)

Returns true if host is an IPv4 address.

const bool = UDX.isIPv6(host)

Returns true if host is an IPv6 address.

const family = UDX.isIP(host)

Returns the address family (4 or 6). Returns 0 if invalid.

Sockets

const socket = udx.createSocket([options])

Creates a new socket instance.

Available options:

{
  ipv6Only: false,
  reuseAddress: false
}

socket.udx

It's the UDX instance from where the socket was created.

socket.streams

It's a Set that tracks active streams (connected to the socket but not closed).

socket.userData

Optional custom userData. Default is null.

socket.bound

Indicates if it's bound to any port. It will be true after a successful bind().

socket.closing

It will be true after close() is called.

socket.idle

Indicates that the socket doesn't have any connected stream.

socket.busy

Indicates that the socket have at least one connected stream.

socket.address()

Returns an object like { host, family, port }. Only available after bind().

socket.bind([port], [host])

The default port is 0.
If no host specified: it binds to IPv6 ::. If fails then IPv4 0.0.0.0.

await socket.close()

It unbinds the socket so it stops listening for messages.

socket.setTTL(ttl)

Sets the amount of times that a packet is allowed to be forwarded through each router or gateway before being discarded.

socket.getRecvBufferSize()

socket.setRecvBufferSize()

socket.getSendBufferSize()

socket.setSendBufferSize()

await socket.send(buffer, port, [host], [ttl])

Sends a message to port and host destination. Default host is 127.0.0.1.

socket.trySend(buffer, port, [host], [ttl])

Same behaviour as send() but no promise.

socket.on('message', (msg, from) => {})

msg is a buffer that containts the message.
from is an object like { host, family, port }.

socket.on('close', onclose)

Emitted if the socket was ever bound and it got closed.

socket.on('idle', onidle)

Emitted if the socket becomes idle (no active streams).

socket.on('busy', onbusy)

Emitted if the socket becomes busy (at least one active stream).

socket.on('listening', onlistening)

Emitted after a succesfull bind() call.

Streams

const stream = udx.createStream(id, [options])

Creates a new stream instance that is a Duplex stream.

Available options:

{
  firewall: (socket, port, host) => true,
  framed: false,
  seq: 0
}

stream.udx

It's the UDX instance from where the stream was created.

stream.socket

Refers to the socket that is connected to. Setted when you connect() the stream.

stream.id

Custom stream id.

stream.remoteId

Remote stream id. Setted when you connect() the stream.

stream.remoteId

Remote stream id. Setted when you connect() the stream.

stream.remoteHost

Remote host. Setted when you connect() the stream.

stream.remoteFamily

Remote family (4 or 6). Setted when you connect() the stream.

stream.remotePort

Remote port. Setted when you connect() the stream.

stream.userData

Optional custom userData. Default is null.

stream.connected

Indicates if the stream is connected to a socket. It becomes false if the stream is closed.

stream.mtu

Indicates the maximum size of each packet.

stream.rtt

stream.cwnd

stream.inflight

stream.localHost

Indicates the connected socket host address. By default null if not connected.

stream.localFamily

Indicates the connected socket family address (4 o 6). By default 0 if not connected.

stream.localPort

Indicates the connected socket port. By default 0 if not connected.

stream.setInteractive(bool)

stream.connect(socket, remoteId, port, [host], [options])

Connects the stream using a socket to a: remote stream id, and remote socket port/host.

If no host specified it uses 127.0.0.1 by default.

Available options:

{
  ack
}

await stream.changeRemote(remoteId, port, [host])

Change the remote end of the stream.

If no host specified it uses 127.0.0.1 by default.

stream.relayTo(destination)

Relay stream to another stream.

await stream.send(buffer)

Send a message to another stream. Returns a promise.

stream.trySend(buffer)

Send a message to another stream.

const drained = await stream.flush()

Wait for pending stream writes to have been explicitly acknowledged by the other side of the connection.

stream.on('connect', onconnect)

Emitted after the stream is connected to a socket.

stream.on('message', onmessage)

Emitted if the stream receives a message.

stream.on('remote-changed', onremotechanged)

Emitted when the remote end of the stream changes.

stream.on('mtu-exceeded', onmtuexceeded)

Emitted only once if you write data that exceeds the MTU.

Network interfaces

const interfaces = udx.networkInterfaces()

Returns an array of network interfaces, for example:

[
  { name: 'lo', host: '127.0.0.1', family: 4, internal: true },
  { name: 'enp4s0', host: '192.168.0.20', family: 4, internal: false },
  { name: 'lo', host: '::1', family: 6, internal: true },
  { name: 'enp4s0', host: 'df08::c8df:bf61:95c1:352b', family: 6, internal: false }
]

const watcher = udx.watchNetworkInterfaces([onchange])

Listens to changes in the network interfaces. The watcher object is iterable.

watcher.interfaces

Array of network interfaces.

watcher.watch()

Starts watching for changes. By default it already does it. This is only useful after you unwatch().

watcher.unwatch()

Stops watching for changes.

await watcher.destroy()

Closes the watcher.

watcher.on('change', onchange)

Emitted after a network interface change.

watcher.on('close', onclose)

Emitted after the watcher is closed.

DNS

const address = await udx.lookup(host, [options])

It does a DNS lookup for the IP address. Returns { host, family }.

Available options:

{
  family: 0 // => 0, 4 or 6
}

Dev Setup

To develop UDX locally, you need to create a libudx prebuild. bare-make is used for this.

Requirements: The Clang C-compiler should be installed.

The other setup steps are:

• npm install -g bare-runtime bare-make
• npm install
• bare-make generate
• bare-make build
• bare-make install

When testing changes, rebuild the prebuilds:

• bare-make generate
• bare-make build
• bare-make install

License

Apache-2.0