2ro
b9a6ec2abc
256KB TCP buffers (was 8KB) + burst 64 (was 1) in smolmix; an IpMixStream::from_client constructor + best_ipr helper and reply-SURBs 10->4 in the ipr wrapper so a caller can back the tunnel with a high-traffic-profile MixnetClient. No behavior change to the default connect_new path used by the scoped exit.
smolmix
TCP/UDP tunnel over the Nym mixnet. Uses a userspace network stack (smoltcp)
to provide real TcpStream and UdpSocket types that work with the async
Rust ecosystem: tokio-rustls, hyper, tokio-tungstenite, libp2p, and anything
else built on AsyncRead + AsyncWrite.
Why IP, not messages
The Nym SDK works at the message layer: you send and receive Vec<u8>
payloads through the mixnet. Every protocol has to be hand-adapted, with
custom framing, ordering, connection state, and flow control.
smolmix operates at the IP layer. A userspace smoltcp stack manages real
TCP state machines (retransmits, windowing, port allocation) and UDP
datagram delivery, and the mixnet becomes the transport underneath. Any
protocol that works over TCP or UDP works over smolmix without adaptation.
┌──────────────────────────────────────────────────────────────────┐
│ Application protocols that "just work" over smolmix │
│ │
│ ┌──────────┐ ┌──────────┐ ┌──────────────┐ ┌────────────────┐ │
│ │ TLS │ │ HTTP/1.1 │ │ WebSocket │ │ libp2p │ │
│ │ (rustls) │ │ (hyper) │ │ (tungstenite)│ │ (noise+yamux) │ │
│ └────┬─────┘ └────┬─────┘ └──────┬───────┘ └───────┬────────┘ │
│ │ │ │ │ │
│ └─────────────┴──────────────┴─────────────────┘ │
│ │ │
│ tokio_smoltcp::TcpStream │
│ (AsyncRead + AsyncWrite, Send, Unpin) │
├──────────────────────────────────────────────────────────────────┤
│ smolmix Tunnel │
│ (smoltcp → mixnet → IPR) │
└──────────────────────────────────────────────────────────────────┘
Quick start
use smolmix::Tunnel;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
let tunnel = Tunnel::new().await?;
// Raw TCP, works with any protocol
let mut tcp = tunnel.tcp_connect("1.1.1.1:80".parse()?).await?;
tcp.write_all(b"GET / HTTP/1.1\r\nHost: 1.1.1.1\r\nConnection: close\r\n\r\n").await?;
// Raw UDP, datagrams over the mixnet
let udp = tunnel.udp_socket().await?;
udp.send_to(&packet, "1.1.1.1:53".parse()?).await?;
Examples
cargo run -p smolmix --example tcp # HTTPS via hyper
cargo run -p smolmix --example udp # DNS via hickory-proto
cargo run -p smolmix --example websocket # WebSocket via tungstenite
Architecture
See core/src/ARCHITECTURE.md for the internal
stack (smoltcp, device adapter, bridge, mixnet client).