Change thread start behaviour

Signed-off-by: trivernis <trivernis@protonmail.com>

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "vented"
 description = "Event driven encrypted tcp communicaton"
-version = "0.9.1"
+version = "0.9.2"
 authors = ["trivernis <trivernis@protonmail.com>"]
 edition = "2018"
 readme = "README.md"

src/server/data.rs

@@ -7,6 +7,7 @@ use executors::crossbeam_workstealing_pool;
 use executors::parker::DynParker;
 use parking_lot::Mutex;
 use std::collections::HashMap;
+use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
 use x25519_dalek::PublicKey;
 
@@ -29,4 +30,5 @@ pub(crate) struct ServerConnectionContext {
     pub forwarded_connections: Arc<Mutex<HashMap<(String, String), AsyncValue<CryptoStream, ()>>>>,
     pub pool: crossbeam_workstealing_pool::ThreadPool<DynParker>,
     pub redirect_handles: Arc<Mutex<HashMap<[u8; 16], AsyncValue<(), VentedError>>>>,
+    pub listener_count: Arc<AtomicUsize>,
 }

src/server/mod.rs

@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use std::net::{TcpListener, TcpStream};
+use std::net::{Shutdown, TcpListener, TcpStream};
 
 use crypto_box::{PublicKey, SecretKey};
 use executors::{crossbeam_workstealing_pool, Executor};
@@ -21,6 +21,7 @@ use parking_lot::Mutex;
 use sha2::Digest;
 use std::io::Write;
 use std::iter::FromIterator;
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;
@@ -75,6 +76,8 @@ pub struct VentedServer {
     global_secret_key: SecretKey,
     node_id: String,
     redirect_handles: Arc<Mutex<HashMap<[u8; 16], AsyncValue<(), VentedError>>>>,
+    listener_count: Arc<AtomicUsize>,
+    num_threads: usize,
 }
 
 impl VentedServer {
@@ -89,6 +92,7 @@ impl VentedServer {
     ) -> Self {
         let mut server = Self {
             node_id,
+            num_threads,
             event_handler: Arc::new(Mutex::new(EventHandler::new())),
             pool: executors::crossbeam_workstealing_pool::pool_with_auto_parker(num_threads),
             connections: Arc::new(Mutex::new(HashMap::new())),
@@ -98,6 +102,7 @@ impl VentedServer {
                 nodes.iter().cloned().map(|node| (node.id.clone(), node)),
             ))),
             redirect_handles: Arc::new(Mutex::new(HashMap::new())),
+            listener_count: Arc::new(AtomicUsize::new(0)),
         };
         server.register_events();
 
@@ -170,6 +175,8 @@ impl VentedServer {
         let context = self.get_server_context();
         let wg = WaitGroup::new();
         let wg2 = WaitGroup::clone(&wg);
+        let num_threads = self.num_threads;
+        let listener_count = Arc::clone(&self.listener_count);
 
         thread::spawn(move || match TcpListener::bind(&address) {
             Ok(listener) => {
@@ -179,8 +186,17 @@ impl VentedServer {
                 for connection in listener.incoming() {
                     match connection {
                         Ok(stream) => {
-                            if let Err(e) = Self::handle_connection(context.clone(), stream) {
+                            let listener_count = listener_count.load(Ordering::Relaxed);
-                                log::error!("Failed to handle connection: {}", e);
+
+                            if listener_count >= num_threads {
+                                log::warn!("Connection limit reached. Shutting down incoming connection...");
+                                if let Err(e) = stream.shutdown(Shutdown::Both) {
+                                    log::error!("Failed to shutdown connection: {}", e)
+                                }
+                            } else {
+                                if let Err(e) = Self::handle_connection(context.clone(), stream) {
+                                    log::error!("Failed to handle connection: {}", e);
+                                }
                             }
                         }
                         Err(e) => log::trace!("Failed to establish connection: {}", e),
@@ -208,6 +224,7 @@ impl VentedServer {
             pool: self.pool.clone(),
             forwarded_connections: Arc::clone(&self.forwarded_connections),
             redirect_handles: Arc::clone(&self.redirect_handles),
+            listener_count: Arc::clone(&self.listener_count),
         }
     }
 
@@ -224,6 +241,7 @@ impl VentedServer {
             .filter(|node| node.address.is_some())
             .cloned()
             .collect::<Vec<Node>>();
+
         for node in public_nodes {
             let payload = RedirectPayload::new(
                 context.node_id.clone(),
@@ -255,15 +273,16 @@ impl VentedServer {
     /// Handles a single connection by first performing a key exchange and
     /// then establishing an encrypted connection
     fn handle_connection(params: ServerConnectionContext, stream: TcpStream) -> VentedResult<()> {
-        let pool = params.pool.clone();
         let event_handler = Arc::clone(&params.event_handler);
         log::trace!(
             "Received connection from {}",
             stream.peer_addr().expect("Failed to get peer address")
         );
 
-        pool.execute(move || {
+        thread::spawn(move || {
             let connections = Arc::clone(&params.connections);
+            let listener_count = Arc::clone(&params.listener_count);
+            listener_count.fetch_add(1, Ordering::Relaxed);
 
             let stream = match VentedServer::get_crypto_stream(params, stream) {
                 Ok(stream) => stream,
@@ -279,6 +298,7 @@ impl VentedServer {
             }
 
             connections.lock().remove(stream.receiver_node());
+            listener_count.fetch_sub(1, Ordering::Relaxed);
         });
 
         Ok(())
@@ -337,6 +357,9 @@ impl VentedServer {
         params: ServerConnectionContext,
         stream: TcpStream,
     ) -> VentedResult<CryptoStream> {
+        stream.set_read_timeout(Some(Duration::from_secs(10)))?;
+        stream.set_write_timeout(Some(Duration::from_secs(10)))?;
+
         let (node_id, stream) = VentedServer::perform_key_exchange(
             params.is_server,
             stream,
@@ -362,19 +385,21 @@ impl VentedServer {
         context.is_server = false;
 
         let connections = Arc::clone(&context.connections);
-        let pool = context.pool.clone();
         let event_handler = Arc::clone(&context.event_handler);
+        let listener_count = Arc::clone(&context.listener_count);
         let stream = Self::get_crypto_stream(context, stream)?;
 
-        pool.execute({
+        thread::spawn({
             let stream = CryptoStream::clone(&stream);
 
             move || {
+                listener_count.fetch_add(1, Ordering::Relaxed);
                 event_handler.lock().handle_event(Event::new(READY_EVENT));
                 if let Err(e) = Self::handle_read(event_handler, &stream) {
                     log::error!("Connection aborted: {}", e);
                 }
                 connections.lock().remove(stream.receiver_node());
+                listener_count.fetch_sub(1, Ordering::Relaxed);
             }
         });
 

tests/test_communication.rs

@@ -43,7 +43,7 @@ fn test_server_communication() {
             trusted: false,
         },
     ];
-    let mut server_a = VentedServer::new("A".to_string(), global_secret_a, nodes.clone(), 6);
+    let mut server_a = VentedServer::new("A".to_string(), global_secret_a, nodes.clone(), 2);
     let mut server_b = VentedServer::new("B".to_string(), global_secret_b, nodes.clone(), 3);
     let mut server_c = VentedServer::new("C".to_string(), global_secret_c, nodes, 3);
     let wg = server_a.listen("localhost:22222".to_string());