➕ add `find-nick` command

README.md

@@ -59,6 +59,19 @@ Run the server manually: (If you haven't installed it with systemd yet)
 lookaround server --nickname my-desktop
 ```
 
+Use `find-nick` to find an IP, or ping it, or SSH into it, or pull a file from it:
+
+```bash
+lookaround find-nick laptop
+
+ping $(lookaround find-nick laptop)
+
+ssh user@$(lookaround find-nick laptop)
+
+# After starting `nc -l -p 9000 < some-file` on the laptop
+nc $(lookaround find-nick laptop) 9000
+``
+
 Run a client to ping all servers in the same multi-cast domain:
 
 ```bash
@@ -71,8 +84,6 @@ Use a longer timeout if some servers need longer than 500 ms to respond:
 lookaround client --timeout-ms 1000
 ```
 
-For less common uses, see [the command-line documentation.](docs/cli.md)
-
 ## Contributing
 Pull requests are welcome. This is a hobby project, so I may reject 
 contributions that are too big to review.

docs/cli.md

@@ -1,3 +0,0 @@
-# Command-line args
-
-

ideas.md

@@ -1,7 +1,6 @@
 Cool ideas that can be done but probably won't be.
 
 - Exit faster if the user only wants to see known servers
-- Command for shell substituting IPs into commands
 - Arbitrary TCP forwarding of (stdin? stdout? TCP?)
 - Netcat replacement "Just send a file" _including filename_
 - Public-key crypto for trusting peers on first use (Hard cause it requires mutable disk state)

src/app_common.rs

@@ -6,6 +6,8 @@ pub enum AppError {
 	AddrParse (#[from] std::net::AddrParseError),
 	#[error (transparent)]
 	CliArgs (#[from] CliArgError),
+	#[error ("Operation timed out")]
+	Elapsed (#[from] tokio::time::error::Elapsed),
 	#[error (transparent)]
 	Io (#[from] std::io::Error),
 	#[error (transparent)]
@@ -26,6 +28,8 @@ pub enum AppError {
 pub enum CliArgError {
 	#[error ("Missing value for argument `{0}`")]
 	MissingArgumentValue (String),
+	#[error ("Missing required argument <{0}>")]
+	MissingRequiredArg (String),
 	#[error ("First argument should be a subcommand")]
 	MissingSubcommand,
 	#[error ("Unknown subcommand `{0}`")]

src/client.rs

@@ -5,66 +5,29 @@ struct ServerResponse {
 	nickname: Option <String>,
 }
 
-pub async fn client <I : Iterator <Item=String>> (mut args: I) -> Result <(), AppError> {
-	use rand::RngCore;
-	
-	let common_params = app_common::Params::default ();
-	let mut bind_addrs = vec! [];
-	let mut timeout_ms = 500;
-	
-	while let Some (arg) = args.next () {
-		match arg.as_str () {
-			"--bind-addr" => {
-				bind_addrs.push (match args.next () {
-					None => return Err (CliArgError::MissingArgumentValue (arg).into ()),
-					Some (x) => Ipv4Addr::from_str (&x)?,
-				});
-			},
-			"--timeout-ms" => {
-				timeout_ms = match args.next () {
-					None => return Err (CliArgError::MissingArgumentValue (arg).into ()),
-					Some (x) => u64::from_str (&x)?,
-				};
-			},
-			_ => return Err (CliArgError::UnrecognizedArgument (arg).into ()),
+struct ClientParams {
+	common: app_common::Params,
+	bind_addrs: Vec <Ipv4Addr>,
+	timeout_ms: u64,
+}
+
+pub async fn client <I: Iterator <Item=String>> (args: I) -> Result <(), AppError> {
+	match get_mac_address() {
+		Ok(Some(ma)) => {
+			println!("Our MAC addr = {}", ma);
 		}
+		Ok(None) => println!("No MAC address found."),
+		Err(e) => println!("{:?}", e),
 	}
 	
-	if bind_addrs.is_empty () {
-		bind_addrs = get_ips ()?;
-	}
-	
-	let socket = UdpSocket::bind (SocketAddrV4::new (Ipv4Addr::UNSPECIFIED, 0)).await?;
-	
-	for bind_addr in bind_addrs {
-		if let Err (e) = socket.join_multicast_v4 (common_params.multicast_addr, bind_addr) {
-			println! ("Error joining multicast group with iface {}: {:?}", bind_addr, e);
-		}
-	}
-	
-	let mut idem_id = [0u8; 8];
-	rand::thread_rng ().fill_bytes (&mut idem_id);
-	
-	let msg = Message::Request1 {
-		idem_id,
-		mac: None,
-	}.to_vec ()?;
-	
-	let socket = Arc::new (socket);
-	let socket2 = Arc::clone (&socket);
-	
-	tokio::spawn (async move {
-		for _ in 0..10 {
-			socket2.send_to (&msg, (common_params.multicast_addr, common_params.server_port)).await?;
-			sleep (Duration::from_millis (100)).await;
-		}
-		
-		Ok::<_, AppError> (())
-	});
+	let params = configure_client (args)?;
+	let socket = make_socket (&params).await?;
+	let msg = Message::new_request1 ().to_vec ()?;
+	tokio::spawn (send_requests (Arc::clone (&socket), params.common, msg));
 	
 	let mut peers = HashMap::with_capacity (10);
 	
-	timeout (Duration::from_millis (timeout_ms), listen_for_responses (&*socket, &mut peers)).await.ok ();
+	timeout (Duration::from_millis (params.timeout_ms), listen_for_responses (&*socket, &mut peers)).await.ok ();
 	
 	let mut peers: Vec <_> = peers.into_iter ().collect ();
 	peers.sort_by_key (|(_, v)| v.mac);
@@ -93,12 +56,130 @@ pub async fn client <I : Iterator <Item=String>> (mut args: I) -> Result <(), Ap
 	Ok (())
 }
 
+pub async fn find_nick <I: Iterator <Item=String>> (mut args: I) -> Result <(), AppError> 
+{
+	let mut nick = None;
+	let mut timeout_ms = 500;
+	
+	while let Some (arg) = args.next () {
+		match arg.as_str () {
+			"--timeout-ms" => {
+				timeout_ms = match args.next () {
+					None => return Err (CliArgError::MissingArgumentValue (arg).into ()),
+					Some (x) => u64::from_str (&x)?,
+				};
+			},
+			_ => nick = Some (arg),
+		}
+	}
+	
+	let needle_nick = nick.ok_or_else (|| CliArgError::MissingRequiredArg ("nickname".to_string ()))?;
+	let needle_nick = Some (needle_nick);
+	
+	let params = ClientParams {
+		common: Default::default (),
+		bind_addrs: get_ips ()?,
+		timeout_ms,
+	};
+	
+	let socket = make_socket (&params).await?;
+	let msg = Message::new_request1 ().to_vec ()?;
+	tokio::spawn (send_requests (Arc::clone (&socket), params.common, msg));
+	
+	timeout (Duration::from_millis (params.timeout_ms), async move { loop {
+		let (msgs, remote_addr) = match recv_msg_from (&socket).await {
+			Err (_) => continue,
+			Ok (x) => x,
+		};
+		
+		let mut resp = ServerResponse {
+			mac: None,
+			nickname: None,
+		};
+		
+		for msg in msgs.into_iter () {
+			match msg {
+				Message::Response1 (x) => resp.mac = x,
+				Message::Response2 (x) => resp.nickname = Some (x.nickname),
+				_ => (),
+			}
+		}
+		
+		if resp.nickname == needle_nick {
+			println! ("{}", remote_addr.ip ());
+			return;
+		}
+	}}).await?;
+	
+	Ok (())
+}
+
+fn configure_client <I: Iterator <Item=String>> (mut args: I) 
+-> Result <ClientParams, AppError>
+{
+	let mut bind_addrs = vec! [];
+	let mut timeout_ms = 500;
+	
+	while let Some (arg) = args.next () {
+		match arg.as_str () {
+			"--bind-addr" => {
+				bind_addrs.push (match args.next () {
+					None => return Err (CliArgError::MissingArgumentValue (arg).into ()),
+					Some (x) => Ipv4Addr::from_str (&x)?,
+				});
+			},
+			"--timeout-ms" => {
+				timeout_ms = match args.next () {
+					None => return Err (CliArgError::MissingArgumentValue (arg).into ()),
+					Some (x) => u64::from_str (&x)?,
+				};
+			},
+			_ => return Err (CliArgError::UnrecognizedArgument (arg).into ()),
+		}
+	}
+	
+	if bind_addrs.is_empty () {
+		bind_addrs = get_ips ()?;
+	}
+	
+	Ok (ClientParams {
+		common: Default::default (),
+		bind_addrs,
+		timeout_ms,
+	})
+}
+
+async fn make_socket (params: &ClientParams) -> Result <Arc <UdpSocket>, AppError> {
+	let socket = UdpSocket::bind (SocketAddrV4::new (Ipv4Addr::UNSPECIFIED, 0)).await?;
+	
+	for bind_addr in &params.bind_addrs {
+		if let Err (e) = socket.join_multicast_v4 (params.common.multicast_addr, *bind_addr) {
+			println! ("Error joining multicast group with iface {}: {:?}", bind_addr, e);
+		}
+	}
+	
+	Ok (Arc::new (socket))
+}
+
+async fn send_requests (
+	socket: Arc <UdpSocket>, 
+	params: app_common::Params,
+	msg: Vec <u8>,
+) 
+-> Result <(), AppError> 
+{
+	for _ in 0..10 {
+		socket.send_to (&msg, (params.multicast_addr, params.server_port)).await?;
+		sleep (Duration::from_millis (100)).await;
+	}
+	
+	Ok::<_, AppError> (())
+}
+
 async fn listen_for_responses (
 	socket: &UdpSocket, 
 	peers: &mut HashMap <SocketAddr, ServerResponse>
 ) {
-	let start_time = Instant::now ();
-	
 	loop {
 		let (msgs, remote_addr) = match recv_msg_from (socket).await {
 			Err (_) => continue,
@@ -118,9 +199,6 @@ async fn listen_for_responses (
 			}
 		}
 		
-		if peers.insert (remote_addr, resp).is_none () {
-			let now = Instant::now ();
-			// println! ("Added peer at {} ms", (now - start_time).as_millis ());
-		}
+		peers.insert (remote_addr, resp);
 	}
 }

src/main.rs

@@ -6,7 +6,7 @@ mod ip;
 pub mod message;
 mod prelude;
 mod server;
-mod tlv;
+pub mod tlv;
 
 fn main () -> Result <(), AppError> {
 	let rt = tokio::runtime::Builder::new_current_thread ()
@@ -24,19 +24,12 @@ async fn async_main () -> Result <(), AppError> {
 	
 	let _exe_name = args.next ();
 	
-	match get_mac_address() {
-		Ok(Some(ma)) => {
-			println!("Our MAC addr = {}", ma);
-		}
-		Ok(None) => println!("No MAC address found."),
-		Err(e) => println!("{:?}", e),
-	}
-	
 	let subcommand: Option <String> = args.next ();
 	
 	match subcommand.as_ref ().map (|x| &x[..]) {
 		None => return Err (CliArgError::MissingSubcommand.into ()),
 		Some ("client") => client::client (args).await?,
+		Some ("find-nick") => client::find_nick (args).await?,
 		Some ("my-ips") => my_ips ()?,
 		Some ("server") => server::server (args).await?,
 		Some (x) => return Err (CliArgError::UnknownSubcommand (x.to_string ()).into ()),

src/message.rs

@@ -1,13 +1,4 @@
-use std::{
-	io::{
-		Cursor,
-		Write,
-	},
-};
-
-use crate::tlv;
-
-use thiserror::Error;
+use crate::prelude::*;
 
 const MAGIC_NUMBER: [u8; 4] = [0x9a, 0x4a, 0x43, 0x81];
 pub const PACKET_SIZE: usize = 1024;
@@ -27,13 +18,25 @@ pub enum Message {
 	Response2 (Response2),
 }
 
+impl Message {
+	pub fn new_request1 () -> Message {
+		let mut idem_id = [0u8; 8];
+		rand::thread_rng ().fill_bytes (&mut idem_id);
+		
+		Message::Request1 {
+			idem_id,
+			mac: None,
+		}
+	}
+}
+
 #[derive (Debug, PartialEq)]
 pub struct Response2 {
 	pub idem_id: [u8; 8],
 	pub nickname: String,
 }
 
-#[derive (Debug, Error)]
+#[derive (Debug, thiserror::Error)]
 pub enum MessageError {
 	#[error (transparent)]
 	Io (#[from] std::io::Error),

src/prelude.rs

@@ -1,6 +1,10 @@
 pub use std::{
 	collections::HashMap,
 	env,
+	io::{
+		Cursor,
+		Write,
+	},
 	net::{
 		Ipv4Addr,
 		SocketAddr,
@@ -18,6 +22,7 @@ pub use mac_address::{
 	MacAddress,
 	get_mac_address,
 };
+pub use rand::RngCore;
 pub use tokio::{
 	net::UdpSocket,
 	time::{
@@ -39,4 +44,5 @@ pub use crate::{
 		PACKET_SIZE,
 		Message,
 	},
+	tlv,
 };

src/server.rs

@@ -10,6 +10,14 @@ struct Params {
 
 pub async fn server <I: Iterator <Item=String>> (args: I) -> Result <(), AppError> 
 {
+	match get_mac_address() {
+		Ok(Some(ma)) => {
+			println!("Our MAC addr = {}", ma);
+		}
+		Ok(None) => println!("No MAC address found."),
+		Err(e) => println!("{:?}", e),
+	}
+	
 	let params = configure (args)?;
 	
 	let socket = UdpSocket::bind (SocketAddrV4::new (Ipv4Addr::UNSPECIFIED, params.common.server_port)).await?;