QUIC for Nim

We're working towards an implementation of the QUIC protocol for Nim. This is very much a work in progress, and not yet in a usable state.

Building and testing

Install dependencies:

nimble install -d

Run tests:

nimble test

Examples

Import quic and the chronos async library:

import quic
import chronos

Outgoing connections

Connect to a QUIC peer:

let connection = await dial(initTAddress("127.0.0.1:12345"))

Open a new stream:

let stream = await connection.openStream()

Write to the stream:

let message = cast[seq[byte]]("some message")
await stream.write(message)

Close stream:

await stream.close()

Wait for peer to close connection:

await connection.waitClosed()

Incoming connections

Listen for incoming connections:

let listener = listen(initTAddress("127.0.0.1:12345"))

Accept an incoming connection:

let connection = await listener.accept()

Wait for an incoming stream:

let stream = await connection.incomingStream()

Read from a stream:

let message = await stream.read()

Close stream:

await stream.close()

Close connection:

await connection.close()

Stop listening:

await listener.stop()

Roadmap

This is a rough outline of the steps that we expect to take during implementation. They are bound to change over time.

• Wrap existing C library for QUIC, to test Nim implementation against
  • Wrap C library with Nimterop
  • Dummy TLS implementation
  • Open connection
  • Complete handshake
  • Create uni-directional stream
  • Create bi-directional stream
  • Send data over stream
  • Close stream
  • Close connection
  • Interface with real TLS library
• Integrate QUIC as a transport in libp2p
• Support IPv6 UDP addresses
• Idle timeouts
• Handle zero-length destination ids
• Packet formats
  • Initial packets
  • 0-RTT packets
  • Handshake packets
  • Retry packets
  • Version negotiation packets
  • Short header packets
• Frames
  • Initial & Handshake frames
    • Padding
    • Ping
    • Ack
    • Crypto
    • Connection close
    • Handshake done
  • Other frames
    • Reset stream
    • Stop sending
    • New token
    • Stream
    • Max data
    • Max stream data
    • Max streams
    • Data blocked
    • Stream data blocked
    • Streams blocked
    • New connection id
    • Retire connection id
    • Path challenge
    • Path response
    • Connection close
• Connections
  • Outgoing (client)
  • Incoming (server)
  • Multiplexing (server)
• Handshake
• Streams
  • Outgoing (writing)
  • Incoming (reading)
  • Uni-directional
  • Bi-directional
• ACKs and retransmissions
• Flow control
• Packet encryption
  • Start by using dummy TLS implementation
  • Select suitable TLS lib
  • Integrate TLS lib
• Loss detection
• Congestion control
• Address validation
• Connection migration
• Version negotiation

Thanks

We would like to thank the authors of the NGTCP2 library, on whose work we're building.