server.rs

mod utils;

use log::debug;
use std::fmt::Write;
use std::os::fd::AsRawFd;

use smoltcp::iface::{Config, Interface, SocketSet};
use smoltcp::phy::{wait as phy_wait, Device, Medium};
use smoltcp::socket::{tcp, udp};
use smoltcp::time::{Duration, Instant};
use smoltcp::wire::{EthernetAddress, IpAddress, IpCidr, Ipv4Address};

fn main() {
    utils::setup_logging("");

    let (mut opts, mut free) = utils::create_options();
    utils::add_tuntap_options(&mut opts, &mut free);
    utils::add_middleware_options(&mut opts, &mut free);
    utils::add_ip_options(&mut opts, &mut free);

    let mut matches = utils::parse_options(&opts, free);
    let device = utils::parse_tuntap_options(&mut matches);
    let ips = utils::parse_ip_options(&mut matches);
    let fd = device.as_raw_fd();
    let mut device =
        utils::parse_middleware_options(&mut matches, device, /*loopback=*/ false);

    // Create interface
    let mut config = match device.capabilities().medium {
        Medium::Ethernet => {
            Config::new(EthernetAddress([0x02, 0x00, 0x00, 0x00, 0x00, 0x01]).into())
        }
        Medium::Ip => Config::new(smoltcp::wire::HardwareAddress::Ip),
        Medium::Ieee802154 => todo!(),
    };

    config.random_seed = rand::random();

    let mut iface = Interface::new(config, &mut device, Instant::now());
    iface.update_ip_addrs(|ip_addrs| {
        ip_addrs
            .push(IpCidr::new(smoltcp::wire::IpAddress::Ipv4(ips.0), 16))
            .unwrap();
    });
    iface
        .routes_mut()
        .add_default_ipv4_route(ips.1)
        .unwrap();

    // Create sockets
    let tcp_rx_buffer = tcp::SocketBuffer::new(vec![0; 64]);
    let tcp_tx_buffer = tcp::SocketBuffer::new(vec![0; 128]);
    let mut tcp_socket = tcp::Socket::new(tcp_rx_buffer, tcp_tx_buffer);

    // TCP_NODELAY
    tcp_socket.set_nagle_enabled(false);

    let mut sockets = SocketSet::new(vec![]);
    let tcp2_handle = sockets.add(tcp_socket);

    let mut tcp_44344_active = false;
    loop {
        let timestamp = Instant::now();
        iface.poll(timestamp, &mut device, &mut sockets);

        // tcp:44344: echo with reverse
        let socket = sockets.get_mut::<tcp::Socket>(tcp2_handle);
        if !socket.is_open() {
            socket.listen(44344).unwrap()
        }

        if socket.is_active() && !tcp_44344_active {
            debug!("tcp:44344 connected");
        } else if !socket.is_active() && tcp_44344_active {
            debug!("tcp:44344 disconnected");
        }
        tcp_44344_active = socket.is_active();

        if socket.may_recv() {
            let data = socket
                .recv(|buffer| {
                    let recvd_len = buffer.len();
                    let mut data = buffer.to_owned();
                    if !data.is_empty() {
                        debug!("tcp:44344 recv data: {:?}", data);
                        data.reverse();
                    }
                    (recvd_len, data)
                })
                .unwrap();
            if socket.can_send() && !data.is_empty() {
                debug!("tcp:44344 send data: {:?}", data);
                socket.send_slice(&data[..]).unwrap();
            }
        } else if socket.may_send() {
            debug!("tcp:44344 close");
            socket.close();
        }

        phy_wait(fd, iface.poll_delay(timestamp, &sockets)).expect("wait error");
    }
}