Netstack Smoltcp

A netstack for the special purpose of turning packets from/to a TUN interface into TCP streams and UDP packets. It uses smoltcp-rs as the backend netstack.

Example

use tun::{Device, TunPacket};
// let device = tun::create_as_async(&cfg)?;
// let framed = device.into_framed();

// let mut builder = StackBuilder::default();
// let (runner, udp_socket, tcp_listener, stack) = builder.build();
// tokio::task::spawn(runner);
let (udp_socket, tcp_listener, stack) = StackBuilder::default().run();

let (mut stack_sink, mut stack_stream) = stack.split();
let (mut tun_sink, mut tun_stream) = framed.split();

// Reads packet from stack and sends to TUN.
tokio::spawn(async move {
    while let Some(pkt) = stack_stream.next().await {
        if let Ok(pkt) = pkt {
            tun_sink.send(TunPacket::new(pkt)).await.unwrap();
        }
    }
});

// Reads packet from TUN and sends to stack.
tokio::spawn(async move {
    while let Some(pkt) = tun_stream.next().await {
        if let Ok(pkt) = pkt {
            stack_sink.send(pkt.into_bytes().into()).await.unwrap();
        }
    }
});

// Extracts TCP connections from stack and sends them to the dispatcher.
tokio::spawn(async move {
    handle_inbound_stream(tcp_listener).await;
});

// Receive and send UDP packets between netstack and NAT manager. The NAT
// manager would maintain UDP sessions and send them to the dispatcher.
tokio::spawn(async move {
    handle_inbound_datagram(udp_socket).await;
});

examples

the example proxy uses our crate - netstack-smoltcp as the userspace implementation, you can run it via

1. sudo cargo run --example proxy -- --interface /your/if/name (macos & linux)
2. cargo run run --example proxy -- --interface /your/if/name (windows, but you need to run the terminal as admin)

but on windows, you should also have wintun.dll installed in C:\Windows\System32

after that, you can set the route table by the following instructions:

windows(run terminal as admin)

1. Get-NetAdapter to check the utun8's if index, assume the index is INDEX
2. route add 1.1.1.1 mask 255.255.255.255 10.10.10..2 if INDEX

linux

sudo ip route add 1.1.1.1/32 dev utun8

macos

sudo route add 146.190.81.132 -interface utun8

so now the have both the proxy program running and the routing table setup correctly, we can have a shot by running: curl 1.1.1.1

or, you can replace the 1.1.1.1 with your server's ipv4 address, and run the iperf3 performance test.

benchmark

see benchmark result

License

This project is licensed under the Apache License 2.0.