Listen for connection on rM instead of host

reStream.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # default values for arguments
-ssh_host="root@10.11.99.1" # remarkable connected through USB
+remarkable="10.11.99.1"    # remarkable connected through USB
 landscape=true             # rotate 90 degrees to the right
 output_path=-              # display output through ffplay
 format=-                   # automatic output format
@@ -19,7 +19,7 @@ while [ $# -gt 0 ]; do
             shift
             ;;
         -s | --source)
-            ssh_host="$2"
+            remarkable="$2"
             shift
             shift
             ;;
@@ -84,12 +84,12 @@ done
 
 ssh_cmd() {
     echo "[SSH]" "$@" >&2
-    ssh -o ConnectTimeout=1 -o PasswordAuthentication=no "$ssh_host" "$@"
+    ssh -o ConnectTimeout=1 -o PasswordAuthentication=no "root@$remarkable" "$@"
 }
 
 # check if we are able to reach the remarkable
 if ! ssh_cmd true; then
-    echo "$ssh_host unreachable or you have not set up an ssh key."
+    echo "$remarkable unreachable or you have not set up an ssh key."
     echo "If you see a 'Permission denied' error, please visit"
     echo "https://github.com/rien/reStream/#installation for instructions."
     exit 1
@@ -185,14 +185,13 @@ fi
 
 set -e # stop if an error occurs
 
-receive_cmd="ssh_cmd ./restream"
-#echo './restream --connect "$(echo $SSH_CLIENT | cut -d " " -f1):61819"'
-#receive_cmd="ssh_cmd 'echo ABC $(echo $SSH_CLIENT | cut -d " " -f1):61819' & ; nc -l -p 61819"
-
 if $unsecure_connection; then
-  echo "Spawning unsecure connection"
-  ssh_cmd 'sleep 0.25 && ./restream --connect "$(echo $SSH_CLIENT | cut -d " " -f1):61819"' &
-  receive_cmd="nc -l -p 61819"
+    listen_port=16789
+    ssh_cmd "./restream --listen $listen_port" &
+    sleep 1 # give some time to restream.rs to start listening
+    receive_cmd="nc 10.11.99.1 $listen_port"
+else
+    receive_cmd="ssh_cmd ./restream"
 fi
 
 # shellcheck disable=SC2086

src/main.rs

@@ -9,18 +9,22 @@ use lz_fear::CompressionSettings;
 use std::default::Default;
 use std::fs::File;
 use std::io::{BufRead, BufReader, Read, Seek, SeekFrom, Write};
+use std::net::{TcpStream, TcpListener};
 use std::process::Command;
+use std::time::Duration;
+use std::thread;
+use std::sync::mpsc::channel;
 
 #[derive(Clap)]
 #[clap(version = crate_version!(), author = crate_authors!())]
 pub struct Opts {
     #[clap(
         long,
-        name = "address",
-        short = 'c',
-        about = "Establish a new unsecure connection to send the data to which reduces some load on the reMarkable and improves fps."
+        name = "port",
+        short = 'l',
+        about = "Listen for an (unsecure) TCP connection to send the data to which reduces some load on the reMarkable and improves fps."
     )]
-    connect: Option<String>,
+    listen: Option<usize>,
 }
 
 fn main() -> Result<()> {
@@ -49,11 +53,8 @@ fn main() -> Result<()> {
     };
 
     let stdout = std::io::stdout();
-    let data_target: Box<dyn Write> = if let Some(ref address) = opts.connect {
-        eprintln!("[rM] Sending stream to {} (instead of stdout)", address);
-        let conn = std::net::TcpStream::connect(address)?;
-        conn.set_write_timeout(Some(std::time::Duration::from_secs(3)))?;
-        Box::new(conn)
+    let data_target: Box<dyn Write> = if let Some(port) = opts.listen {
+        Box::new(listen_timeout(port, Duration::from_secs(3))?)
     } else {
         Box::new(stdout.lock())
     };
@@ -63,6 +64,23 @@ fn main() -> Result<()> {
         .context("Error while compressing framebuffer stream")
 }
 
+fn listen_timeout(port: usize, timeout: Duration) -> Result<TcpStream> {
+    let listen_addr = format!("0.0.0.0:{}", port);
+    let listen = TcpListener::bind(&listen_addr)?;
+    eprintln!("[rM] listening for a TCP connection on {}", listen_addr);
+
+    let (tx, rx) = channel();
+    thread::spawn(move || {
+        tx.send(listen.accept()).unwrap();
+    });
+
+    let (conn, conn_addr) = rx.recv_timeout(timeout)
+        .context("Timeout while waiting for host to connect to reMarkable")??;
+    eprintln!("[rM] connection received from {}", conn_addr);
+    conn.set_write_timeout(Some(timeout))?;
+    Ok(conn)
+}
+
 fn remarkable_version() -> Result<String> {
     let content = std::fs::read("/sys/devices/soc0/machine")
         .context("Failed to read /sys/devices/soc0/machine")?;