Sending PDUs

While the network protocol is not required to be UDP, this crate has been validated against UDP topology, and the example code provided uses UDP as the protocol.

Dependencies

This demonstration utilizes the open_dis_rust crate as well as the bytes and tokio crates.

Create and Serialize the PDU

As shown in the previous section, we can create a PDU as such:

#![allow(unused)]
fn main() {
use open_dis_rust::simulation_management::acknowledge_pdu::AcknowledgePdu;

let mut ack_pdu = AcknowledgePdu::default();
}

Then, we need to create an empty, mutable byte array into which we will serialize the PDU:

#![allow(unused)]
fn main() {
use bytes::BytesMut;

let mut bytes = BytesMut::new();
}

Now, we simply call the serialize function from the PDU and pass in a mutable reference to the byte array:

#![allow(unused)]
fn main() {
ack_pdu.serialize(&mut bytes);
}

The PDU has now been serialized into the byte array and is ready to be sent.

Initializing a UDP Socket

We need to select an address and a port to send the message. For this exercise, we will assume the address is localhost (127.0.0.1), and we will use port 3000. To create the socket, we use the tokio crate:

use bytes::BytesMut;
use std::net::SocketAddr;
use std::io;
use tokio::net::UdpSocket;

use open_dis_rust::simulation_management::acknowledge_pdu::AcknowledgePdu;

#[tokio::main]
async fn main() -> io::Result<()> {
    let socket = UdpSocket::bind("0.0.0.0:3000").await?;
    let remote_addr = "127.0.0.1:3000";

    socket.connect(remote_addr).await?;
  
    let mut ack_pdu = AcknowledgePdu::default();
    let mut bytes = BytesMut::new();

    ack_pdu.serialize(&mut bytes);
    socket.send(&bytes[..]).await?;
}

We create a UDP socket and bind it to all network interfaces, specifically on port 3000. We then establish a one-to-one connection to 127.0.0.0:3000. Afterwards, we take our serialized PDU and send it via the socket's send() function. Anything listening on 127.0.0.1:3000 will be able to receive the message.

A tutorial on receiving and parsing a PDU is available in the next section.