proto/rwhod: improve de/serialization and datatypes

src/bin/roowhod.rs

@@ -1,10 +1,41 @@
-fn main() {
-    println!(
-        "{:#?}",
-        roowho2_lib::server::rwhod::generate_rwhod_status_update(),
-    );
-    println!(
-        "{:#?}",
-        roowho2_lib::server::rwhod::determine_relevant_interfaces(),
-    );
+use std::net::SocketAddrV4;
+
+use anyhow::Context;
+use chrono::Timelike;
+use roowho2_lib::proto::{Whod, WhodStatusUpdate};
+
+const RWHOD_BROADCAST_PORT: u16 = 513;
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let addr = SocketAddrV4::new(std::net::Ipv4Addr::UNSPECIFIED, RWHOD_BROADCAST_PORT);
+    let socket = tokio::net::UdpSocket::bind(addr).await?;
+    socket.set_broadcast(true)?;
+
+    let mut buf = [0u8; Whod::MAX_SIZE];
+    loop {
+        let (len, src) = socket.recv_from(&mut buf).await?;
+        if len < Whod::HEADER_SIZE {
+            eprintln!(
+                "Received too short packet from {src}: {len} bytes (needs to be at least {} bytes)",
+                Whod::HEADER_SIZE
+            );
+            continue;
+        }
+        let result: WhodStatusUpdate = Whod::from_bytes(&buf[..len])
+            .context("Failed to parse whod packet")?
+            .try_into()
+            .map(|mut status_update: WhodStatusUpdate| {
+                let timestamp = chrono::Utc::now()
+                    .with_nanosecond(0)
+                    .unwrap_or(chrono::Utc::now());
+                status_update.recvtime = Some(timestamp);
+                status_update
+            })
+            .map_err(|e| anyhow::anyhow!("Invalid whod packet: {}", e))?;
+
+        println!("Received whod packet from {src}:\n{result:#?}");
+
+        buf = [0u8; Whod::MAX_SIZE];
+    }
 }