A pure Rust TCP library that can be simply used in place of TCP implementations provided by operating systems, enabling services to be built with uncommon flexibility.
At a high level, it provides APIs similar to any asynchronous TCP socket library.
To start listening, use TcpListener
.
But instead of binding to a single SocketAddr
,
give it the name of a TUN network interface:
use ustunet::TcpListener;
let mut listener = TcpListener::bind("tuna").unwrap();
And it will process all IP packets going to the interface,
accepting incoming TCP connections destined to any SocketAddr
.
It's like binding to all possible IP and ports.
(But without the complexity or the cost.
Only one file descriptor is used.)
Accept TcpStream
s:
while let Some(tcp_stream) = listener.next().await {
}
Use tokio::io::AsyncRead
and AsyncWrite
implementations:
let mut buf = [0u8; 1024];
let n = tcp_stream.read(&mut buf).await.unwrap();
tcp_stream.write("Aloha!".as_bytes()).await.unwrap();
Since the listener is not bound to an address,
the SocketAddr
actually used by a connection can be of more interest.
let server_addr = socket.local_addr();
println!("Provided service on port {}, IP: {}.", server_addr.port(), server_addr.ip());
Similarly, call peer_addr
to get the address of the host that initiated the connection.
Add to Cargo.toml
[dependencies.ustunet]
git = "https://github.com/ustcp/ustcp.git"
TUN allows a user to send and receive IP packets on the interface with no permission requirements at runtime.
Create a TUN interface with name set to tuna
, and ownership given to user yuki
.
And bring it up.
sudo ip Tuntap add dev tuna mode tun user yuki
sudo ip link set up dev tuna
Give it an IP address (and a subnet mask) that's not currently in use:
sudo ip addr add 192.168.9.100/24 dev tuna
With the subnet mask /24
,
ustunet will be able to respond on any address in the range from 192.168.9.1
to 192.168.9.254
.
The command can be repeated to add more addresses,
but adding routes can be more flexible.
Configure any address in the subnet as a gateway for a different range of IPs
to instruct the operating systems to contact those addresses also via tuna
.
sudo ip route add 10.33.0.0/16 via 192.168.9.4 dev tuna