add ttl parameter on send command

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mctk"
-version = "0.1.2"
+version = "0.1.3"
 authors = ["curtis@ruck.io"]
 edition = "2018"
 description = "multicast toolkit (mctk)"

README.md

@@ -54,6 +54,7 @@ OPTIONS:
     -i, --interval <milliseconds>    Sets the sender's packet transmission interval [default: 1000]
     -s, --packet-size <bytes>        Sets the sender's packet size [default: 1000]
     -p, --port <port>                Sets the multicast port [default: 8201]
+    -t, --ttl <ttl>                  Sets the sender's time to live value [default: 2]
 ```
 ```bash
 $ mctk help receive

src/lib.rs

@@ -47,11 +47,13 @@ pub fn join_multicast(addr: SocketAddr) -> io::Result<UdpSocket> {
     Ok(socket.into_udp_socket())
 }
 
-pub fn new_sender() -> io::Result<Socket> {
+pub fn new_sender(ttl: u8) -> io::Result<Socket> {
     let socket = new_socket()?;
 
     socket.set_multicast_if_v4(&Ipv4Addr::new(0, 0, 0, 0))?;
 
+    socket.set_multicast_ttl_v4(u32::from(ttl))?;
+
     socket.bind(&SockAddr::from(SocketAddr::new(
         Ipv4Addr::new(0, 0, 0, 0).into(),
         0,
@@ -64,7 +66,7 @@ pub fn send_message(socket: &Socket, destination: SocketAddr, packet_size: u16,
     let message = generate_message(packet_size, msgid);
     socket
         .send_to(message.as_bytes(), &SockAddr::from(destination))
-        .expect(&format!("could not send {} to {}", message, destination));
+        .expect("Unable to send message");
 }
 
 pub fn generate_message(size: u16, count: u32) -> String {

src/main.rs

@@ -55,6 +55,15 @@ fn main() {
                         .help("Sets the sender's packet size")
                         .default_value("1000")
                         .takes_value(true),
+                )
+                .arg(
+                    Arg::with_name("ttl")
+                        .short("t")
+                        .long("ttl")
+                        .value_name("ttl")
+                        .help("Sets the sender's time to live value")
+                        .takes_value(true)
+                        .default_value("2"),
                 ),
         )
         .subcommand(
@@ -87,9 +96,10 @@ fn main() {
         let sleep_interval: Duration =
             Duration::from_millis(matches.value_of("interval").unwrap().parse().unwrap());
         let packet_size: u16 = matches.value_of("packet-size").unwrap().parse().unwrap();
+        let ttl: u8 = matches.value_of("ttl").unwrap().parse().unwrap();
         let destination_addr = SocketAddr::new(group, port);
         println!("Running a sender to {}", destination_addr);
-        let socket: socket2::Socket = lib::new_sender().expect("could not create sender");
+        let socket: socket2::Socket = lib::new_sender(ttl).expect("could not create sender");
         let mut count: u32 = 0;
         while true {
             count += 1;

tests/multicast.rs

@@ -9,7 +9,7 @@ fn test_multicast() {
 
     let mut rcvbuf = [0u8; 65536];
 
-    let sender = mctk::new_sender().expect("unable to create sender");
+    let sender = mctk::new_sender(1).expect("unable to create sender");
     let listener = mctk::join_multicast(sockaddr).expect("unable to create multicast listener");
 
     mctk::send_message(&sender, sockaddr, 50, 17);