Adding sockets

In the previous section, we created device with an interface. We already used a SocketSet, however, this one was empty. Let's create a TcpSocket and add it to the SocketSet:

#![allow(unused)]
fn main() {
let mut sockets = SocketSet::new(vec![]);

let tcp_socket = TcpSocket::new(
    TcpSocketBuffer::new(vec![0;1500]),
    TcpSocketBuffer::new(vec![0;1500]),
);

let tcp_handle = sockets.add(tcp_socket);
}

Now, we can use the TcpSocket to connect to a remote host:

#![allow(unused)]
fn main() {
let remote_addr = Ipv6Address::new(0xfe80, 0, 0, 0, 0, 0, 0, 2);
let remote_port = 4242;
let host_port = 4343;

let socket = socket.get_mut::<tcp::Socket>(tcp_handle);
socket.connect(iface.context(), (remote_addr, remote_port), host_port).unwrap();
}

The TcpSocket will now try to connect to the remote host. However, we still need to poll the interface to make sure that the TcpSocket can send and receive packets.

#![allow(unused)]
fn main() {
loop {
    if let Err(e) = iface.poll(&mut sockets, Instant::now()) {
        println!("Network error: {:?}", e);
        continue;
    }
}
}

The TcpSocket is now ready to send and receive data.

#![allow(unused)]
fn main() {
loop {
    if let Err(e) = iface.poll(&mut sockets, Instant::now()) {
        println!("Network error: {:?}", e);
        continue;
    }

    let mut socket = sockets.get::<TcpSocket>(tcp_handle);
    
    if !socket.is_open() {
        println!("Connection closed");
        break;
    }
    
    if socket.can_send() {
        socket.send_slice(b"Hello world!").unwrap();
    }
    
    if socket.can_recv() {
        let data = socket.recv(|data| {
            println!("Received data: {:?}", data);
            (data.len(), data)
        }).unwrap();
    }
}
}

Other socket types

The TcpSocket is not the only socket type available. There are also the following types:

• Dhcpv4Socket: a DHCPv4 client socket;
• UdpSocket: a UDP socket;
• DnsSocket: a DNS client socket;
• IcmpSocket: an ICMP socket. This socket type is used to send and receive ICMP packets and might listen for specific ICMP error messages related to a UDP/TCP port;
• RawSocket: a raw socket. This socket type is used to send and receive raw packets.