main: Send beacons to the all-nodes link-local multicast group

* Use `async_std::task` for network loops
 * Send the generated public key over ipv4 udp broadcast frames

(peer discovery is not functional yet, although multiple instances
connected to the same link can now talk to each other, so yay.)

src/main.rs

@@ -1,17 +1,52 @@
-use async_std::fs;
-use async_std::net::UdpSocket;
+use async_std::{fs, task};
+use async_std::net::{UdpSocket, Ipv6Addr};
 use async_std::path::PathBuf;
+use async_std::sync::Arc;
 use clap::{load_yaml, App};
 use ed25519_dalek::Keypair;
 
 mod keypair;
-use keypair::SSBKeypair;
+use keypair::{SSBKeypair, SSBPublicKey};
 
 mod network;
 use network::Peer;
 
 type Config = toml::map::Map<String, toml::Value>;
 
+async fn peer_discovery_recv() {
+    let socket = UdpSocket::bind(":::8008").await.unwrap();
+    let all_nodes_addr = Ipv6Addr::new(0xFF02, 0, 0, 0, 0, 0, 0, 0x02);
+    let mut buf = [0u8; 1024];
+
+    socket.join_multicast_v6(&all_nodes_addr, 0).unwrap();
+
+    loop {
+        let (amt, peer) = socket.recv_from(&mut buf).await.unwrap();
+        let buf = &mut buf[..amt];
+        let packet = String::from_utf8(buf.to_vec()).unwrap();
+        println!(
+            "{} {}",
+            peer,
+            Peer::from_discovery_packet(&packet).to_discovery_packet()
+        );
+    }
+}
+
+async fn peer_discovery_send(pubkey: Arc<String>) {
+    let socket = UdpSocket::bind(":::0").await.unwrap();
+    let msg = format!("net:1.2.3.4:8023~shs:{}", &pubkey);
+    let buf = msg.as_bytes();
+
+    socket.set_broadcast(true).unwrap();
+
+    loop {
+        println!("Sending packet: {:?}", &msg);
+        socket.send_to(&buf, "255.255.255.255:8008").await.unwrap();
+        socket.send_to(&buf, "[FF02::2]:8008").await.unwrap();
+        task::sleep(std::time::Duration::from_secs(1)).await;
+    }
+}
+
 #[async_std::main]
 async fn main() {
     let options = load_yaml!("options.yaml");
@@ -39,17 +74,8 @@ async fn main() {
     let keypair = Keypair::read_or_generate(path.join("secret")).await;
     println!("{}", keypair.to_json().pretty(2));
 
-    let socket = UdpSocket::bind(":::8008").await.unwrap();
-    let mut buf = [0u8; 1024];
+    let pubkey = keypair.public.to_base64();
 
-    loop {
-        let (amt, peer) = socket.recv_from(&mut buf).await.unwrap();
-        let buf = &mut buf[..amt];
-        let packet = String::from_utf8(buf.to_vec()).unwrap();
-        println!(
-            "{} {}",
-            peer,
-            Peer::from_discovery_packet(&packet).to_discovery_packet()
-        );
-    }
+    task::spawn(peer_discovery_recv());
+    task::spawn(peer_discovery_send(Arc::new(pubkey))).await;
 }