clean up

# Conflicts:
#	src/bin/client.rs

.gitignore

@@ -59,3 +59,78 @@ Icon
 Network Trash Folder
 Temporary Items
 .apdisk
+
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+.vscode/launch.json

Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+crypto_box = "0.8.2"

src/bin/client.rs

@@ -1,26 +1,85 @@
+use std::io::Write;
 use std::net::TcpStream;
+use crypto_box::{
+    aead::{Aead, AeadCore, OsRng},
+    SalsaBox, PublicKey, SecretKey
+};
 
 fn main() {
-    let stream = TcpStream::connect("127.0.0.1:8080");
-    if stream.is_ok() {
-        println!("Connected to the server!");
-    } else {
-        println!("Couldn't connect to server...");
-    }
+    let port: u32 = 7878;
+    //let stream = TcpStream::connect("172.30.16.1:8080");
+    //let stream = TcpStream::connect("27.0.0.1:8080");
+    match TcpStream::connect(format!("localhost:{}", port)) {
+        Ok(mut stream) => {
+            println!("Successfully connected to server");
 
-    loop {
-        let mut buffer = String::new();
-        match std::io::stdin().read_line(&mut buffer) {
-            Ok(n) => {
-                if n == 0 {
-                    break;
+            let bob_init_pub_key = PublicKey::from([
+                0xe8, 0x98, 0xc, 0x86, 0xe0, 0x32, 0xf1, 0xeb,
+                0x29, 0x75, 0x5, 0x2e, 0x8d, 0x65, 0xbd, 0xdd,
+                0x15, 0xc3, 0xb5, 0x96, 0x41, 0x17, 0x4e, 0xc9,
+                0x67, 0x8a, 0x53, 0x78, 0x9d, 0x92, 0xc7, 0x54,
+            ]);
+            let (salsa_box, pub_key) = generate_box(bob_init_pub_key.clone());
+
+            loop {
+                let mut buffer = String::new();
+                match std::io::stdin().read_line(&mut buffer) {
+                    Ok(n) => {
+                        if n == 0 {
+                            break; // Beenden bei EOF
+                        }
+                        //
+                        // Encryption
+                        //
+
+                        // Get a random nonce to encrypt the message under
+                        let nonce = SalsaBox::generate_nonce(&mut OsRng);
+
+                        // Message to encrypt
+                        let plaintext = buffer.trim().as_bytes();
+
+                        // Encrypt the message using the box
+                        let ciphertext = salsa_box.encrypt(&nonce, &plaintext[..]).expect("Fehler");
+
+                        println!("Sending {0} as {1:?}", buffer.trim(), plaintext);
+                        stream.write(buffer.as_bytes()).unwrap();
+
+                        //
+                        // Decryption
+                        //
+
+                        // Decrypt the message, using the same randomly generated nonce
+                        let decrypted_plaintext = salsa_box.decrypt(&nonce, &ciphertext[..]).expect("Fehler");
+                        let dec_plain_plaintext = std::str::from_utf8(&*decrypted_plaintext).expect("Nö");
+                        assert_eq!(&plaintext[..], &decrypted_plaintext[..]);
+
+                        println!("Sent {0:?} as cypher: {1:?}, decrypted: {2:?}, {3}", plaintext, ciphertext, decrypted_plaintext, dec_plain_plaintext);
+                    }
+                    Err(error) => {
+                        println!("error: {error}");
+                        break;
+                    }
                 }
-                println!("{}", buffer);
-            }
-            Err(_error) => {
-                println!("Fehlerhafte Eingabe!");
-                break;
             }
         }
+        Err(e) => {
+            println!("Failed to connect: {}", e);
+        }
     }
-} // the stream is closed here
+    println!("Terminated.");
+}
+
+fn generate_box(partner_public_key: PublicKey) -> (SalsaBox, PublicKey) {
+    // Generate a random secret key.
+    // NOTE: The secret key bytes can be accessed by calling `secret_key.as_bytes()`
+    let own_secret_key = SecretKey::generate(&mut OsRng);
+
+    // Get the public key for the secret key we just generated
+    let own_public_key = own_secret_key.public_key().clone();
+
+    // Create a `SalsaBox` by performing Diffie-Hellman key agreement between
+    // the two keys.
+    let salsa_box = SalsaBox::new(&partner_public_key, &own_secret_key);
+    (salsa_box, own_public_key)
+}
+

src/bin/server.rs

@@ -1,31 +1,53 @@
 use std::{
-    io::{prelude::*, BufReader},
+    io::{prelude::*, BufReader, Lines},
     net::{TcpListener, TcpStream},
 };
-use std::io::Lines;
+use std::thread::available_parallelism;
+use crate::thread_pool::ThreadPool;
+
+mod thread_pool;
+
 
 fn main() {
+    // start server on localhost (for remote access use: 0.0.0.0)
     let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    
+    // create thread pool (size = no. of cpu cores)
+    let pool = ThreadPool::new(available_parallelism().unwrap().get());
 
+    // handling function for incoming requests
     for stream in listener.incoming() {
         let stream = stream.unwrap();
 
-        handle_connection(stream);
+        // pass request to thread pool
+        pool.execute(|| {
+            handle_connection(stream);
+        });
     }
+    println!("Shutting down.");
 }
 
+
 fn handle_connection(mut stream: TcpStream) {
+    // clone TcpStream for simultaneous receiving and sending
     let mut stream2: TcpStream = stream.try_clone().unwrap();
+
+    // initialize reading buffer (for better performance!)
     let buf_reader: BufReader<&mut TcpStream> = BufReader::new(&mut stream);
+    // request: read received text line by line (continuous until connection closed)
     let request: Lines<BufReader<&mut TcpStream>> = buf_reader.lines();
 
     println!("Request: {:#?}", request);
 
+    // processing function for every text line received by request (terminates when conn closed)
     for elem in request
     {
+        // store received line in variable s
         let s = elem.unwrap();
         println!("{:?}", s);
-        stream2.write(s.as_bytes()).unwrap();
+
+        // send received line back to sender (append LF)
+        stream2.write_all(s.as_bytes()).unwrap();
         stream2.write_all(b"\n").unwrap();
     }
 }

src/bin/thread_pool.rs

@@ -0,0 +1,116 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread
+};
+
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: Option<mpsc::Sender<Job>>,
+}
+
+// Box: pointer for heap allocation (smart pointer); dyn: unknown type to compile time
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        // create asynchronous channel with sender/receiver pair (for jobs!)
+        let (sender, receiver) = mpsc::channel();
+
+        // protect receiver with thread-safe shared (Arc) mutex to avoid multiple access
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        // pre(!)allocate space for workers
+        let mut workers = Vec::with_capacity(size);
+
+        // initialize all workers...
+        for id in 0..size {
+            // create worker with unique id and pointer to the shared mutex
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        // set thread pool variables
+        ThreadPool {
+            workers,
+            // Some --> enum variant (Option): indicates that sender may not exist (=be null)
+            sender: Some(sender),
+        }
+    }
+
+    pub fn execute<F>(&self, f: F)
+        where
+            // FnOnce() --> only callable once; Send --> transfer to another thread; 'static --> lifetime
+            F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        // commit job to sender object --> pass to threads for execution
+        self.sender.as_ref().unwrap().send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        // drop sender first
+        drop(self.sender.take());
+
+        // then drop workers
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            // join worker thread
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    /// Create a new Worker..
+    ///
+    /// The id is a unique identifier.
+    /// The receiver is a shared pointer to a receiver protected by Mutex.
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        // spawn thread and enter infinite loop
+        let thread = thread::spawn(move || loop {
+            // lock mutex and wait for job
+            let message = receiver.lock().unwrap().recv();
+
+            match message {
+                // normal operation --> execute job
+                Ok(job) => {
+                    println!("Worker {id} got a job; executing.");
+
+                    job();
+                }
+                // exit gracefully when pool is closed --> recv will return error then
+                Err(_) => {
+                    println!("Worker {id} disconnected; shutting down.");
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}